Sources and management of nitrogen before or after irrigation on the winter wheat and bean production / Fontes de nitrogênio e manejo antes ou após a irrigação nas culturas do trigo e feijoeiro "de inverno"

Studies that demonstrate the effects of sources of nitrogen (N) applied before or after irrigation on the yield of winter crops are limited in literature. In this sense, the objective of this study was to compare the effect of sources of N applied immediately before or after 13 mm irrigation of wheat and bean winter crops. It was used a randomized complete block design, with 4 replicates, in a 5 × 2 + 1 factorial scheme, and 11 treatments consisted of five N sources: urea, polymer-coated urea, urea + ammonium sulfate, ammonium sulfate, and ammonium nitrate and a control treatment (without N fertilization). For wheat, although ammonium nitrate provided great N content in the leaves, the grain yield was lower due to the lodging of the plants; since the application of N either before or after irrigation did not influence the grain yield. Regarding the bean, N fertilization increased productivity, but there were no differences among N sources and, despite the greater N content in the leaves observed with the N supply before irrigation the greatest grain yield was observed when N was applied after the irrigation.

Estudos que demonstram os efeitos de fontes de nitrogênio (N) aplicadas antes ou após a irrigação na produtividade das culturas de inverno são limitados na literatura. Neste sentido, o objetivo deste trabalho foi comparar o efeito de fontes de N aplicadas imediatamente antes ou após a irrigação de 13 mm nas culturas do trigo e feijão de inverno. Utilizou-se o delineamento de blocos casualizados, com 4 repetições, em esquema fatorial incompleto 5 × 2 + 1, sendo 11 tratamentos com cinco fontes de N: ureia, ureia revestida com polímero, ureia + sulfato de amônio, sulfato de amônio e nitrato de amônio e um tratamento controle (sem adubação nitrogenada). Para o trigo, embora o nitrato de amônio tenha proporcionado maior teor de N nas folhas, a produtividade de grãos foi menor devido ao acamamento das plantas; já a aplicação de N antes ou após a irrigação não influenciou a produtividade de grãos. Com relação ao feijão, a adubação nitrogenada aumentou a produtividade, mas não houve diferenças entre as fontes de N e, apesar do maior teor de N nas folhas observadas com o suprimento de N antes da irrigação, a maior produtividade de grãos foi observada com a adubação após a irrigação.

Sowing density and clipping management: effects on the architecture and yield of dual-purpose wheat / Densidade de semeadura e manejo da corte: efeitos na arquitetura e rendimento do trigo de duplicação

The dual-purpose wheat stands out as a complementary alternative for forage supply during the winter period. Therefore, this work had the objective of evaluate the performance characteristics in five genotypes of dual-purpose wheat submitted to different sowing densities and different clipping managements. The experiment was carried out during the 2016 and 2017 harvests. The experimental design was a randomized block design, organized in a factorial scheme, with five dual-purpose wheat genotypes (BRS Tarumã, BRS Umbu, BRS Figueira, BRS Guatambu and BRS 277) x five sowing densities (75, 150, 225, 300 and 375 seeds m²) x four clipping operations (zero, one, two and three clippings), arranged in three replicates. The measuring of characters were number of fertile tillers, seeds yield, angle of flag leaf, chlorophyll content and flowering. The genotype BRS Tarumâ is superior in number of fertile tillers and chlorophyll index for all the sowing densities, as well, the flowering is influenced direct by clipping managements. The sowing density of 75 seeds m-2 is not indicated for dual-purpose wheat independent of the clipping management. The seeds yield is amplified thought the increase in sowing density, however, advancing in clipping levels there is a decrease in forage yield.

O trigo de duplo propósito se destaca como uma alternativa complementar para o fornecimento de forragem durante o período de inverno. Portanto, este trabalho teve como objetivo avaliar as características de desempenho de cinco genótipos de trigo de duplo propósito submetidos a diferentes densidades de semeadura e diferentes manejos de corte. O experimento foi realizado durante as safras de 2016 e 2017. O delineamento experimental foi em blocos ao acaso, organizado em esquema fatorial, com cinco genótipos de trigo de duplo propósito (BRS Tarumã, BRS Umbu, BRS Figueira, BRS Guatambu e BRS 277) x cinco densidades de semeadura (75, 150, 225, 300 e 375 m² de sementes) x quatro operações de clipagem (zero, um, dois e três recortes), dispostos em três repetições. As medidas dos caracteres foram número de perfilhos férteis, rendimento de sementes, ângulo de folha de bandeira, teor de clorofila e floração. O genótipo BRS Tarumâ é superior em número de perfilhos férteis e índice de clorofila para todas as densidades de semeadura, assim como o florescimento é influenciado diretamente pelos manejos de corte. A densidade de semeadura de 75 sementes m-2 não é indicada para trigo de dupla finalidade independente do manejo de corte. O rendimento das sementes é amplificado pelo aumento da densidade de semeadura, entretanto, avançando nos níveis de recorte, há uma diminuição no rendimento de forragem.

Involvement of putrescine in osmotic stress-induced ABA signaling in leaves of wheat seedlings

To elucidate one mechanism by which putrescine (Put) functions in plant signaling under osmotic stress, Put and ABAcontents, and plasma membrane-NADPH oxidase (PM-NOX) activity were detected in wheat seedling leaves. Underosmotic stress, ABA and Put contents, PM-NOX activity, and PM-NOX-dependent O2.- production all increased. Theinhibitor tungstate (T) of ABA bio-synthesis reduced the increases in ABA and Put contents under osmotic stress. Theinhibitor D-arginine (D-Arg) of Put bio-synthesis didn’t reduce osmotic-induced increase of ABA, but it inhibited theincreases of PM-NOX activity and O2. - production, and the inhibitory effects were reversed by exogenous Put. Thesefindings suggested that ABA might regulate Put biosynthesis, and Put might regulate PM-NOX activity. Treatments withthree inhibitors imidazole (I), diphenylene iodonium (DPI) and pyridine (P) of PM-NOX reduced significantly not only O2. -production, but also the stress-induced increase of Put content, which indicated that O2. - production might regulate Putbiosynthesis. Treatments with EGTA (Ca2? chelator), La3? and verapamil (V) (Ca2? channel blockers) reduced significantly the stress-induced increase of Put content, which suggested that Ca2? might regulate Put biosynthesis. With thesefindings, it could be concluded that Put was involved in ABA signaling induced by osmotic stress via regulating PM-NOXactivity in wheat seedling leaves.

PDIL1-2 can indirectly and negatively regulate expression of the AGPL1 gene in bread wheat

BACKGROUND: ADP-glucose pyrophosphorylase (AGPase), the key enzyme in plant starch biosynthesis, is a heterotetramer composed of two identical large subunits and two identical small subunits. AGPase has plastidial and cytosolic isoforms in higher plants, whereas it is mainly detected in the cytosol of grain endosperms in cereal crops. Our previous results have shown that the expression of the TaAGPL1 gene, encoding the cytosolic large subunit of wheat AGPase, temporally coincides with the rate of starch accumulation and that its overexpression dramatically increases wheat AGPase activity and the rate of starch accumulation, suggesting an important role. METHODS: In this study, we performed yeast one-hybrid screening using the promoter of the TaAGPL1 gene as bait and a wheat grain cDNA library as prey to screen out the upstream regulators of TaAGPL1 gene. And the barley stripe mosaic virus-induced gene-silencing (BSMV-VIGS) method was used to verify the functional characterization of the identified regulators in starch biosynthesis. RESULTS: Disulfide isomerase 1-2 protein (TaPDIL1-2) was screened out, and its binding to the TaAGPL1-1D promoter was further verified using another yeast one-hybrid screen. Transiently silenced wheat plants of the TaPDIL1-2 gene were obtained by using BSMV-VIGS method under field conditions. In grains of BSMV-VIGS-TaPDIL1-2-silenced wheat plants, the TaAGPL1 gene transcription levels, grain starch contents, and 1000-kernel weight also significantly increased. CONCLUSIONS: As important chaperones involved in oxidative protein folding, PDIL proteins have been reported to form hetero-dimers with some transcription factors, and thus, our results suggested that TaPDIL1-2 protein could indirectly and negatively regulate the expression of the TaAGPL1 gene and function in starch biosynthesis.

Knock-down the expression of TaH2B-7D using virus-induced gene silencing reduces wheat drought tolerance

BACKGROUND: Drought is a major abiotic stress affecting global wheat (Triticum aestivum L.) production. Exploration of drought-tolerant genes is essential for the genetic improvement of drought tolerance in wheat. Previous studies have shown that some histone encoding genes are involved in plant drought tolerance. However, whether the H2B family genes are involved in drought stress response remains unclear. METHODS: Here, we identified a wheat histone H2B family gene, TaH2B-7D, which was significantly up-regulated under drought stress conditions. Virus-induced gene silencing (VIGS) technology was used to further verify the function of TaH2B-7D in wheat drought tolerance. The phenotypic and physiological changes were examined in the TaH2B-7D knock-down plants. RESULTS: In the TaH2B-7D knock-down plants, relative electrolyte leakage rate and malonaldehyde (MDA) content significantly increased, while relative water content (RWC) and proline content significantly decreased compared with those in the non-knocked-down plants under drought stress conditions. TaH2B-7D knock-down plants exhibited severe sagging, wilting and dwarf phenotypes under drought stress conditions, but not in the non-knocked-down plants, suggesting that the former were more sensitive to drought stress. CONCLUSION: These results indicate that TaH2B-7D potentially plays a vital role in conferring drought tolerance in wheat.

Identification and characterization of CircRNAs involved in the regulation of wheat root length

BACKGROUND: Recent studies indicate that circular RNAs (circRNAs) may play important roles in the regulation of plant growth and development. Plant roots are the main organs of nutrient and water uptake. However, whether circRNAs involved in the regulation of plant root growth remains to be elucidated. METHODS: LH9, XN979 and YN29 are three Chinese wheat varieties with contrasting root lengths. Here, the root circRNA expression profiles of LH9, XN979 and YN29 were examined by using high-throughput sequencing technology. RESULTS: Thirty-three and twenty-two differentially expressed circRNAs (DECs) were identified in the YN29-LH9 comparison and YN29-XN979 comparison, respectively. Among them, ten DECs coexisted in both comparisons. As the roots of both LH9 and XN979 were significantly larger and deeper than YN29, the ten DECs coexisting in the two comparisons were highly likely to be involved in the regulation of wheat root length. Moreover, three of the ten DECs have potential miRNA binding sites. Real-time PCR analysis showed that the expression levels of the potential binding miRNAs exhibited significant differences between the long root plants and the short root plants. CONCLUSIONS: The expression levels of some circRNAs exhibited significant differences in wheat varieties with contrasting root phenotypes. Ten DECs involved in the regulation of wheat root length were successfully identified in which three of them have potential miRNAs binding sites. The expression levels of putative circRNA-binding miRNAs were correlated with their corresponding circRNAs. Our results provide new clues for studying the potential roles of circRNAs in the regulation of wheat root length.

Biomass production of wheat grown under different waterlogging conditions and the impact on seed vigor / Produção de biomassa de trigo cultivada sob diferentes condições de alagamento do solo e impacto no vigor de sementes

The aims of this study are to provide a comparative analysis of the growth and the expression of seed vigor from wheat plants subjected to periods of waterlogging during the development period. The treatments consisted of different combinations of soil waterlogging: T1 = no waterlogging; T2 = two waterlogging periods, at stages Z25 and Z45; and T3 = three waterlogging periods, at stages Z25, Z45 and Z75. Plants were collected at regular intervals after emergence until the end of the cycle: 14, 28, 42, 56, 70, 84, 98 and 112 days after emergence (DAE). Dry mass and leaf area of samples were determined. From the primary data, the analysis of growth was applied, and the total dry mass, dry matter production, relative growth and net assimilation rates, leaf area, leaf area ratio, leaf mass ratio and specific leaf area were calculated. Seedling emergence, seedling emergence rate index and dry mass of seedling shoots and roots were also evaluated. Wheat plants grown in conditions of field capacity demonstrated better performance compared to those subjected to three periods of soil waterlogging, with higher total dry mass and net assimilation rates. Seedling emergence and seedling emergence rate index did not differ between treatments. However, soil waterlogging for two or three periods resulted in a reduction in the dry matter of roots and shoots of wheat seedlings. The growth of wheat plants was found to be negatively affected by soil waterlogging. The expression of seed vigor from plants not exposed to soil waterlogging was similar to that of plant seeds subjected to soil waterlogging, although seedling growth was affected negatively by waterlogging conditions.

O objetivo deste estudo é fornecer uma análise comparativa do crescimento e da expressão do vigor das sementes das plantas de trigo submetidas a períodos de alagamento do solo durante o ciclo de desenvolvimento. Os tratamentos consistiram em diferentes combinações de alagamento do solo: T1 = sem alagamento do solo; T2 = dois períodos de alagamento do solo, nos estágios Z25 e Z45; e T3 = três períodos de alagamento do solo, nos estádios Z25, Z45 e Z75. As plantas foram coletadas em intervalos regulares após a emergência até o final do ciclo: 14, 28, 42, 56, 70, 84, 98 e 112 dias após a emergência (DAE). Foi determinada a massa seca e a área foliar das amostras. A partir dos dados primários, foi aplicada a análise do crescimento, calculando-se a massa seca total, a taxa de produção de matéria seca, o crescimento relativo e a taxa de assimilatória líquida, área foliar, razão de área foliar, razão de massa foliar e área foliar específica. A emergência de plântulas, o índice de emergência das plântulas e a massa seca de parte aérea e raízes de plântulas foram avaliados. As plantas de trigo cultivadas em condições de capacidade de campo demonstraram melhor desempenho em comparação com aqueles submetidos a três períodos de alagamento do solo, com maior massa seca total e taxa de assimilatória líquida. O índice de emergência e o índice de emergência de plântulas não diferiram entre os tratamentos. No entanto, o alagamento do solo durante dois ou três períodos resultou em uma redução na matéria seca de raízes e de parte aérea de plântulas de trigo. O crescimento das plantas de trigo foi afetado negativamente pelo alagamento do solo. A expressão do vigor das sementes de plantas não expostas ao alagamento do solo foi semelhante à das sementes de plantas submetidas ao alagamento do solo, embora o crescimento das plântulas tenha sido afetado negativamente pelas condições de inundação.

Organic acid carriers in tolerance to toxic aluminum in wheat / Transportadores de ácidos orgânicos na tolerância ao alumínio tóxico em trigo

ABSTRACT: Aluminum (Al) toxicity in plants is seen in about 15% of the soils worldwide, restraining yields in arable land. In Brazil, acidic soils limit production of wheat (Triticum aestivum L.) and other cereals. Al is toxic for most winter cereals when its concentration increases and soil pH is below 5. One of the main concerns with acidic soil is the increase in the mobility of Al3+ions. Al binds to cell walls in roots, preventing meristematic elongation in sensitive species, causing damage to the root system and results in lower yields. Al3+ forms highly stable complexes with phosphorus (P), limiting its availability to plants, as well as reducing cell division and elongation. To deal with Al toxicity, plants have developed strategies such as organic acid (OA) exudation by roots; this mechanism of detoxification has been well-characterized. OAs, in turn, chelate ions Al3, forming non-toxic compounds that do not penetrate the root system. Some genes responsible for Al tolerance in wheat have been identified, particularly TaALMT1 and TaMATE1B that transport malate and citrate OAs, respectively. In this review, we discussed the mechanisms by which Al damages roots those by which plants are protected, primarily through two genes. We also described the interaction of the ALMT1 gene with P and iron (Fe).

RESUMO: A toxicidade do alumínio (Al) às plantas é observada em cerca de 15% dos solos no planeta, sendo um fator restritivo à produtividade em terras cultiváveis. No Brasil, os solos ácidos são limitantes à produção de trigo (Triticum aestivum L.) e outros cereais. O Al é tóxico para a maioria dos cereais de inverno, quando a sua concentração aumenta e o pH do solo atinge valores inferiores a 5. Uma das principais preocupações sobre o solo ácido é o aumento da mobilidade dos íons Al3+. O Al pode se ligar as paredes celulares das raízes e, como consequência, impedir o alongamento meristemático em espécies sensíveis, provocando danos ao sistema radicular, que resulta em menor desempenho agronômico das plantas. O Al3+ é também capaz de formar complexos altamente estáveis com fósforo (P), limitando sua disponibilidade para as plantas, e também reduzindo a divisão e o alongamento celular. Para lidar com a toxicidade ao Al, as plantas desenvolveram algumas estratégias como a exsudação de ácido orgânicos (AOs) pelas raízes, sendo este mecanismo de destoxificação bem caracterizado. Os AOs, por sua vez, quelam ions Al3+ formando compostos não tóxicos que não penetram no sistema radicular. Alguns genes responsáveis pela tolerância ao Al em trigo foram identificados, com ênfase para TaALMT1 e TaMATE1B, que exsudam os AOs malato e citrato, respectivamente. Nesta revisão, discutimos os mecanismos pelos quais Al danifica raízes, bem como plantas protegem-se, através de dois genes principalmente. Também apresentamos a interação do gene ALMT1 com P e ferro (Fe).

QTLs for seedling traits under salinity stress in hexaploid wheat / Caracterização de QTLs por traços de sementes sob o estresse de salinidade em trigo Hexaploid

ABSTRACT: Soil salinity limits agricultural production and is a major obstacle for increasing crop yield. Common wheat is one of the most important crops with allohexaploid characteristic and a highly complex genome. QTL mapping is a useful way to identify genes for quantitative traits such as salinity tolerance in hexaploid wheat. In the present study, a hydroponic trial was carried out to identify quantitative trait loci (QTLs) associated with salinity tolerance of wheat under 150mM NaCl concentration using a recombinant inbred line population (Xiaoyan 54×Jing 411). Values of wheat seedling traits including maximum root length (MRL), root dry weight (RDW), shoot dry weight (SDW), total dry weight (TDW) and the ratio of TDW of wheat plants between salt stress and control (TDWR) were evaluated or calculated. A total of 19QTLs for five traits were detected through composite interval mapping method by using QTL Cartographer version 2.5 under normal and salt stress conditions. These QTLs distributed on 12 chromosomes explained the percentage of phenotypic variation by individual QTL varying from 7.9% to 19.0%. Among them, 11 and six QTLs were detected under normal and salt stress conditions, respectively and two QTLs were detected for TDWR. Some salt tolerance related loci may be pleiotropic. Chromosome 1A, 3A and 7A may harbor crucial candidate genes associated with wheat salt tolerance. Our results would be helpful for the marker assisted selection to breed wheat varieties with improved salt tolerance.

RESUMO: A salinidade do solo limita a produção agrícola. O trigo mole é uma das culturas mais importantes com característica allohexaploid e genoma altamente complexo. O mapeamento QTL é uma maneira muito útil de identificar genes para traços quantitativos, como a tolerância à salinidade em trigo hexaplóide. No presente estudo realizou-se um ensaio hidropónico para identificar locos de traços quantitativos (QTLs) associados à tolerância à salinidade do trigo sob concentração de NaCl 150 mM, usando uma população de linhagem consanguíneo recombinante (Xiaoyan 54 × Jing 411). Os valores dos traços de mudas de trigo, incluindo comprimento máximo da raiz (MRL), peso seco da raiz (RDW), ponha o peso seco (SDW), peso seco total (TDW) e a proporção das plantas de trigo TDW entre o estresse salgado e o controle (TDWR), foram avaliados ou calculados. Um total de 19QTLs para cinco traços foram detectados através do método de mapeamento de intervalo composto usando a versão 2.5 do cartógrafo QTL sob condições normais e de estresse salino. Estes QTLs distribuídos em 12 cromossomos explicaram a porcentagem de variação fenotípica por QTL individual variando de 7,9% a 19,0%. Entre eles, foram detectados 11 e 6 QTLs em condições de estresse normal e sal, respectivamente, e dois QTLs foram detectados para TDWR. Cromossoma 1A, 3A e 7A podem conter genes que são candidatos cruciais associados à tolerância ao sal de trigo. Nossos resultados seriam úteis para a seleção assistida por marcadores para produzir variedades de trigo com tolerância salina melhorada.

Population structure of Chinese southwest wheat germplasms resistant to stripe rust and powdery mildew using the DArT-seq technique / População de germoplasmas resistentes de trigo empregando a técnica de sequenciamento Dart-seq

ABSTRACT: Understanding genetic variability in existing wheat accessions is critical for collection, conservation and use of wheat germplasms. In this study, 138 Chinese southwest wheat accessions were investigated by genotyping using two resistance gene makers (Pm21 and Yr26) and DArT-seq technique. Finally, about 50% cultivars (lines) amplified the specific allele for the Yr26 gene (Gwm11) and 40.6% for the Pm21 gene (SCAR1265). By DArT-seq analysis, 30,485 markers (6486 SNPs and 23999 DArTs) were obtained with mean polymorphic information content (PIC) value 0.33 and 0.28 for DArT and SNP marker, respectively. The mean Dice genetic similarity coefficient (GS) was 0.72. Two consistent groups of wheat varieties were identified using principal coordinate analysis (PCoA) at the level of both the chromosome 6AS and the whole-genome, respectively. Group I was composed of non-6VS/6AL translocation lines of different origins, while Group II was composed of 6VS/6AL translocation (T6VS/6AL) lines, most of which carried the Yr26 and Pm21 genes and originated from Guizhou. Besides, a model-based population structure analysis revealed extensive admixture and further divided these wheat accessions into six subgroups (SG1, SG2, SG3, SG4, SG5 and SG6), based on their origin, pedigree or disease resistance. This information is useful for wheat breeding in southwestern China and association mapping for disease resistance using these wheat germplasms in future.

RESUMO: O conhecimento da estrutura da população é essencial para o mapeamento de associação de resistência a doenças para a população de trigo. Neste estudo, a técnica de DART-seq™ foi usada para genotipar o genoma inteiro de cultivares de trigo. Finalmente, 30,485 marcadores (6486 SNPs e 23999 dardos) foram obtidos, e dois grupos de variedades de trigo foram identificados por meio de análise principal-coordenadas (PCoA) do nível de todo o genoma e o nível 6AS cromossomo. O grupo I foi composto por linhas não T6VS/6Al de diferentes origens, enquanto o Grupo II foi composto de linhas T6VS/6Al, sendo que da maioria destes realizados os genes Yr26 e PM21 originários de Guizhou.

Identification and characterization of circRNAs involved in the regulation of low nitrogen-promoted root growth in hexaploid wheat

BACKGROUND: CircRNAs are widespread in plants and play important roles in response to abiotic stresses. Low nitrogen (LN) promotes the growth of plant root system, allowing it to explore more nitrogen. However, whether circRNAs involved in the response to LN stress and the regulation of LN-promoted root growth in wheat remains unclear. METHODS: Two wheat varieties (LH9 and XN979) with contrasting root phenotypes to LN stress were used as materials to identify circRNAs under control and LN conditions by using high-throughput sequencing technology. RESULTS: Six differentially expressed circRNAs (DECs) involved in the common response to LN stress and 23 DECs involved in the regulation of LN-promoted root growth were successfully identified. GO analysis of the DEC-host genes involved in the regulation of LN-promoted root growth showed that GO terms related to biological regulation, responses to stimuli and signalling were significantly enriched. Moreover, seven DECs were predicted to have miRNA binding sites and may serve as miRNA sponges to capture miRNAs from their target genes. CONCLUSIONS: LN stress altered the expression profiles of circRNAs in wheat. This is the first report of LN stress responsive circRNAs in plants. Our results provided new clues for investigating the functions of circRNAs in response to LN stress and in the regulation of LN-promoted wheat root growth.

Transcriptome analysis for the restrained stem development of the wheat mutant dms / Desenvolvimento e análise de transcriptoma de uma haste de trigo mutante dms

ABSTRACT: Wheat (Triticum aestivum L.) stem development significantly affects grain yield. The dwarf plants (D) of wheat mutant dms was less than 30cm. Here, we were to explore the molecular basis for the restrained stem development of the dwarf plants. The results were reached by compare the young spikes and stems transcriptomes of the tall (T) and D plants of mutant dms. We identified 663 genes highly expressed in stem tips. We identified 997 differentially expressed genes (DEGs) in stem tips between T and D, 403 DEGs were significantly related with stem development. Most biological processes in stem tips on dwarf plants were significantly suppressed, such as phytohormone signaling etc. The sequencing analysis results were confirmed by quantitatively analysis the expression profiles of fourteen key DEGs via real-time QRT-PCR. We identified a group genes related to wheat stem development, identified a group DEGs related to the restrained stem development of D plants of dms. The suppressed phytohormone signaling, carbohydrate transport and metabolism were the major causal factors leading to dwarf plants of D. Our dataset provides a useful resource for investigating wheat stem development.

RESUMO: O desenvolvimento da haste do trigo (Triticum aestivum L.) afeta significativamente o rendimento dos grãos. A partir disso, empregou-se a base molecular para o desenvolvimento de uma haste de variedade de trigo. Os resultados foram alcançados ao conferir as hastes de um mutante de trigo DMS. Identificou-se 663 genes altamente expressos na haste; 997 genes (DEGs) diferentemente expressos em hastes entre T e D e; 403 DEGs foram significativamente diferentes. A maioria dos processos biológicos de caule tipo não plantas foram significativamente suprimidas, com o fito hormônio de sinalização. Os resultados da análise de sequencia foram confirmados pela expressão quantitativa de perfis de catorze chave DEGs através de qRT-PCR em tempo real. Nota-se um grupo de genes relacionados com a haste de trigo de desenvolvimento. Identificou-se um grupo DEGs relacionados com o desenvolvimento de um tronco D plantas de DMS. O fito hormônio de sinalização, transporte e metabolismo de hidratos de carbono foram os principais fatores suscetíveis das plantas anão de D. Nosso conjunto de dados fornece um recurso útil para investigar o desenvolvimento do caule de trigo.

CD 1252: health, quality and tolerance to pre-harvest sprouting / CD 1252: sanidade, qualidade e tolerancia a germinação

Resulting from the search for wheat cultivars with high yield potential, plant health, processing quality and tolerance to pre-harvest sprouting, CD 1252 was developed from the cross between cultivar IPR 85 and line OR1/3/BOW/GLENSON//BAGULA. Cultivar CD 1252 was tested in preliminary grain yield trials in 2005 and 2006, and then tested to determine the Value for Cultivation and Use (VCU) from 2007 to 2014, labelled CD 0711. All tests were arranged in an experimental design of randomized blocks, with three replications. The yield of cultivar CD 1252 was 5%, 4% and 1% higher than the average yield of the two best controls, respectively, in the wheat-growing regions VCU 2, 3 and 4. The wheat quality, potential for grain yield, and tolerance to pre-harvest sprouting of this cultivar are superior and it is tolerant to the main wheat diseases.

Buscando cultivares de potencial produtivo, sanidade, qualidade industrial e tolerância a germinação na espiga, foi desenvolvida a cultivar de trigo CD 1252, obtida do cruzamento entre a cultivar IPR 85 e a linhagem OR 1/3/BOW/GLENSON//BAGULA. A cultivar CD 1252, participou dos Ensaios Preliminares de rendimento de grãos em 2005 e 2006, sendo em seguida testada em Ensaios de Valor de Cultivo e Uso (VCU), nos anos de 2007 a 2014, com a sigla CD 0711. Todos os ensaios foram conduzidos em delineamento experimental de blocos ao acaso, com três repetições. A cultivar CD 1252 apresentou rendimento 5%, 4% e 1% superior à média das duas melhores testemunhas, respectivamente, nas Regiões Tritícolas de VCU 2, 3 e 4. A referida cultivar tem qualidade superior (trigo melhorador), alto potencial de rendimento de grãos, tolerância à germinação na espiga e tolerância às principais doenças.

Respiratory activity in wheat seeds as related to physiological quality / Atividade respiratória em sementes de trigo correlacionada com a qualidade fisiológica

Seeds are a very important input for crops, and the use of low quality seeds and/or inadequate management affects the germination and hampers seedling emergence, which reduces the plant stand. There is a critical need for the development of rapid methods, which are both reliable and easy to perform, for evaluating the physiological potential of seeds. This would streamline the decision-making process regarding the management of lots and allow for the identification of seed lots of inadequate quality in the seed processing unit, which could then be discarded, and would consequently result in reduced costs associated with unnecessary processing. However, it is important that these methods are low cost and quick to perform. The aim of this study was to evaluate the correlation of respiratory activity of wheat seed, through Pettenkofer test, with tests that evaluate seeds physiological quality. We selected a seed lot of high physiological quality, then subjected the seeds to adverse temperature and relative humidity conditions to obtain different vigor levels. The adverse conditions used were 42ºC and 100% relative humidity, for periods of 6, 36, 66 and 96 hours. This process obtained seeds of five vigor levels which were subjected to the following tests: germination, field emergence, electrical conductivity, shoot and root length, total dry mass and respiratory activity. The results showed a negative correlation between respiratory activity and germination, emergence, shoot and root length and dry weight, whereas germination and emergence were strongly correlated with respiratory activity, r = -0.86 and r = -0.81, respectively. There was a significant positive correlation between conductivity and respiratory activity. Therefore, the respiratory activity test using the Pettenkofer method was correlated with other vigor tests, and allowed the classification of wheat seeds into lots of different levels of quality.

As sementes são um atributo muito importante para a cultura, sendo que o uso de sementes de baixa qualidade e/ou a gestão inadequada afeta a germinação e dificulta a emergência das plântulas, reduzindo o estande de plantas. A necessidade de métodos rápidos, confiáveis e de fácil execução é fundamental para a avaliação do potencial fisiológico das sementes. Eles poderiam agilizar as tomadas de decisões referentes ao manejo dos lotes e permitir o descarte de lotes de sementes com qualidade inadequada, na unidade de recepção e processamento de sementes, com a consequente redução de custos de um provável processamento desnecessário. Entretanto, é importante que os mesmos sejam de baixo custo e consideravelmente rápidos. O objetivo do presente trabalho foi correlacionar a atividade respiratória de sementes de trigo, através do teste de Pettenkofer, com testes que avaliam a qualidade fisiológica das sementes. Foi selecionado um lote de sementes com alta qualidade fisiológica e as mesmas foram submetidas a condições adversas de temperatura e umidade relativa do ar para obter diferentes níveis de vigor. As condições adversas foram de 42 ºC e 100% de umidade relativa, por períodos de seis, 36, 66 e 96 horas. Com o processo obteve-se cinco níveis de vigor e estas sementes foram submetidas aos seguintes testes: germinação, emergência a campo, condutividade elétrica, comprimento de parte aérea e raiz, massa seca total e atividade respiratória. Os resultados mostraram correlação negativa entre a atividade respiratória e os testes de germinação, emergência, comprimento da parte aérea e da raiz, e massa seca, sendo que o teste de germinação e a emergência apresentaram alta correlação com a atividade respiratória, r = -0,86 e r = - 0,81, respectivamente. Já a correlação da condutividade elétrica com a respiração foi significativa e positiva. Portanto, conclui-se que o teste da atividade respiratória pelo método de Pettenkofer se correlaciona com outros testes de vigor e permite a classificação dos lotes de sementes de trigo em diferentes níveis de qualidade.

Molecular marker linked to the rb1 gene and association with pre-harvest sprouting tolerance in wheat / Marcador molecular ligado ao gene rb1 em trigo e associação com a tolerância à germinação pré-colheita

The objective of this study was to identify microsatellites molecular markers linked to R genes, that confer the wheat grain color and evaluate the association with pre-harvest sprouting tolerance. This study was conducted with a F2 population with 203 plants, derived from the cross between PFAU x CD0666 genotypes, which segregates for one grain color gene. Were analyzed 43 molecular markers located in regions that containing R genes on 3B and 3D chromosomes. The Xbarc344 molecular marker was identified as linked to the R gene at a distance of 26.1 cM with 83.25% of selection efficiency. From the phenotypic analysis was confirmed the association between grain color with Xbarc344 molecular marker, however, there was no association between Xbarc344 with pre-harvest sprouting tolerance. Also, there was no association between grain color with pre-harvest sprouting tolerance. Although the grain color in wheat is a trait easy to select, it is known that not all R genes are involved with pre-harvest sprouting tolerance. Therefore, it is important the genetic mapping and specific evaluation of each R gene with pre-harvest sprouting tolerance. Thus, the molecular markers identified as associated with each R gene can be used to select plants that contain such genes, since it is not possible to identify phenotypically which R gene each plant has.

O objetivo deste trabalho foi identificar marcadores moleculares microssatélites ligados aos genes R, que conferem a cor do grão em trigo e avaliar a associação com a tolerância à germinação na espiga. O estudo foi realizado em uma população com 203 plantas F2, derivadas do cruzamento entre os genótipos PFAU x CD0666, que segregam para um gene da cor do grão. Foram analisados 43 marcadores moleculares localizados nas regiões que contêm os genes R nos cromossomos 3B e 3D. Foi identificado que o marcador Xbarc344 está ligado ao gene R a uma distância de 26,1 cM e apresentou eficiência de seleção de 83,25%. A partir da análise fenotípica foi possível confirmar a associação da cor do grão com o marcador Xbarc344, no entanto, não houve associação deste marcador e da cor do grão com a tolerância à germinação na espiga. Embora a cor do grão seja uma característica fácil de selecionar em trigo, é notório que nem todos os genes R estão envolvidos com a tolerância à germinação na espiga. Sendo assim, é importante o mapeamento genético e a avaliação específica da associação de cada gene R com esta característica. Assim, os marcadores moleculares identificados como associados a cada gene R podem ser utilizados para selecionar plantas que contenham tais genes, uma vez que não é possível identificar fenotipicamente qual gene R cada planta possuí.

Health and quality of zinc coated wheat seeds during storage / Sanidade e qualidade de sementes de trigo recobertas com zinco durante o armazenamento

The objective was to evaluate the effect of seed wheat coated with zinc, in its physiological, sanitary attributes and enzyme quality, during storage. We used two batches of seed, for seed treatment, we used commercial product as a source of zinc in the form of ZnSO4, along with fungicide and polymer. It was tested for levels 0, 1, 2, 3 and 4 mL ZnSO4 kg-1 seed. The physiological quality, during the storage period, was analyzed by the tests: moisture content, hectoliter weight, germination, emergence, index emergence rate, tetrazolium and sanity test. It was concluded that the doses 3 mL and 4 mL of ZnSO4 to assist in the ultimate expression of the seeds physiological quality, until six months stocked. This coating promotes a smaller reduction in the viability of seeds, furthermore, results in a lower incidence of fungi on seeds during storage. Also help to maximize the expression of physiological seed quality of higher and lower quality, respectively. The micronutrient zinc associated with fungicide and polymer had a lower incidence of fungi during the storage period.

O objetivo do presente trabalho foi avaliar o efeito do recobrimento de sementes de trigo com zinco, por meio de atributos fisiológicos e sanitários durante o armazenamento. Foram utilizados dois lotes de sementes e para tratamento, utilizou-se produto comercial com fonte de zinco na forma de ZnSO4, fungicida e polímero. Foram testados níveis de 0; 1; 2; 3 e 4 mL de ZnSO4.kg-1 de semente. A avaliação da qualidade fisiológica, durante o período de armazenamento foi realizada por: teor de água, peso hectolítrico, germinação, emergência de plântulas, índice de velocidade de emergência e teste de tetrazólio e o teste de sanidade. Concluiu-se que o recobrimento de sementes de trigo com sulfato de zinco nas doses de 3 a 4 mL. kg-1 de semente, são eficientes na maximização da qualidade fisiológica das sementes, até seis meses de armazenamento. Este recobrimento promove menor redução na viabilidade das sementes, além disso, resulta em menor incidência de fungos nas sementes durante o armazenamento. Também auxiliam na maximização da expressão da qualidade fisiológica das sementes de maior e menor qualidade, respectivamente. O micronutriente zinco associado com fungicida e polímero apresentaram menor incidência de fungos ao longo do período de armazenamento.

CD 154: strong gluten wheat with high yield potential / CD 154: trigo melhorador e de alto potencial produtivo

Wheat breeding programs focus on potential grain yield, industrial quality, low plant height, and disease resistance. Cultivar CD 154 was a result of the search for cultivars with high yield potential and industrial wheat quality. This cultivar was derived from a cross between CD 104 and CDI 200104, by COODETEC, in 1999. Cultivar CD 154 was included in preliminary grain yield trials in 2005 and 2006, and was then tested to determine the Value of Cultivation and Use (VCU) from 2007 to 2012, with the acronym CD 0705. All trials were arranged in an experimental design of randomized blocks with three replications. The yield of cultivar CD 154 was 16 %, 10 % and 4 % higher than the mean yield of the two best controls, respectively, in the wheat-growing regions VCU 2, 3 and 4. The analysis of industrial quality, resulted in a mean gluten strength of 364 and mean stability of 17.1 min, which allows the inclusion cultivar CD 154 in the cultivar group of strong gluten wheat. The cultivar is classified as strong gluten wheat, has a high yield potential and good lodging resistance, and is therefore another promising alternative for wheat farmers of the hottest regions of Brazil.

Os programas de melhoramento de trigo estão direcionados para potencial de rendimento de grãos, qualidade industrial, baixa estatura de planta e resistência às doenças. Buscando cultivares de potencial produtivo e qualidade industrial foi desenvolvida a cultivar de trigo CD 154. Está cultivar, foi obtida do cruzamento entre as cultivares CD 104 e CDI 200104, pela COODETEC, em 1999. A cultivar CD 154, participou dos Ensaios Preliminares de rendimento de grãos em 2005 e 2006, sendo em seguida testada em Ensaios de Determinação de Valor e Uso (VCU), nos anos de 2007 a 2012, com a sigla CD 0705. Todos os ensaios foram conduzidos em delineamento experimental de blocos ao acaso, com três repetições. A cultivar CD 154 apresentou um rendimento 16%, 10% e 4% superior à média das duas melhores testemunhas, respectivamente, nas Regiões Tritícolas de VCU 2, 3 e 4. Os resultados de análise de qualidade industrial geraram uma média 364 de força geral de glúten e uma estabilidade média de 17,1 minutos, o que permite incluir a cultivar CD 154 no grupo de cultivares de trigo melhorador. A referida cultivar possui qualidade trigo melhorador, alto potencial de rendimento de grãos, boa resistência ao acamamento, sendo assim mais uma opção importante aos triticultores das Regiões mais quentes do Brasil.

Mycobiota and occurrence of Fumonisin B1 in wheat harvested in Southern Brazil / Micobiota e ocorrência de Fumonisina B1 em trigo colhido no Sul do Brasil

Although fumonisin B1 (FB1) is a mycotoxin poorly studied in wheat, the Fusarium genus fungi have been frequently detected in this cereal, especially in subtropical regions such as southern Brazil, thus studies on their occurrence are required. This study evaluated the mycobiota, water activity and the presence of FB1 in 11 wheat cultivars grown in the northeastern and northwestern of Rio Grande do Sul. The mycobiota was identified by morphological and molecular techniques and FB1 was determined by liquid chromatography with fluorescence detection (HPLC-FL). Microbial counts lower than 103CFU were found in the samples, and the fungi genera Phoma, Cladosporium and Fusarium were the most frequent. Despite this, 54% of the samples were contaminated with FB1 at levels ranging from 958 to 4,906µg FB1 kg-1.

Embora Fumonisina B1 (FB1) seja uma micotoxina pouco estudada em trigo, os fungos do gênero Fusarium são frequentemente detectados neste cereal, principalmente em regiões subtropicais, como o Sul do Brasil, o que justifica a necessidade de avaliar sua ocorrência. Neste estudo, foram avaliadas a micobiota, atividade de água e a presença de FB1 em 11 cultivares de trigo cultivados nas regiões nordeste e noroeste do Rio Grande do Sul. A micobiota foi identificada por técnicas morfológicas e moleculares e a FB1 foi determinada por cromatografia líquida e detecção por fluorescência (HPLC-FL). Nas amostras analisadas, foi verificada uma contagem inferior a 103UFC, e os fungos dos gêneros Phoma, Cladosporium e Fusarium foram os mais frequentes. Apesar disso, 54% das amostras estavam contaminadas com FB1 em níveis variando de 958 a 4906µg de FB1 kg-1.

In silico structural and functional analysis of protein encoded by wheat early salt-stress response gene (WESR3).

Salt stress is one of the major abiotic stresses limiting grain yield in wheat (Triticum aestivum L.). Wheat early salt-stress response gene (WESR3) is one of the major salt stress genes, which is affected in the first phase of salt stress. In this study, sequence and structural analysis of protein coded by WESR3 gene was carried out using various bioinformatics tools. Sequence analysis of WESR3 protein revealed the presence of highly conserved regions of Mlo gene family. Three-dimensional modeling was carried out to elucidate its structure and its active site. The sequence analysis revealed that WESR3 protein might be involved in fungal pathogen attack pathway. Thus, in addition to its involvement in abiotic stresses, it also seemed to play an important part in biotic stress pathways. Out of the three modeled protein structures obtained from I-TASSER, HHPred and QUARK, the I-TASSER protein model was the best model based on high confidence score and lesser number of bad contacts. The Ramchandran plot analysis also showed that all amino acid residues of I-TASSER model lie in the allowed region and thus indicating towards the overall good quality of the predicted model. Seventeen active sites were predicted in the protein bearing resemblance to the Mlo family conserved regions. In conclusion, a detailed analysis of WESR3 protein suggested an important role of WESR3 in biotic and abiotic stress. These results aid to the experimental data and help to build up a complete view of WESR3 proteins and their role in plant stress response.

Induced defence responses of contrasting bread wheat genotypes under differential salt stress imposition.

Plants, being sessile in nature, have developed mechanisms to cope with high salt concentrations in the soil. In this study, the effects of NaCl (50-200 mM) on expression of high-affinity potassium transporters (HKTs), antioxidant enzymes and their isozyme profiles were investigated in two contrasting bread wheat (Triticum aestivum L.) genotypes viz., HD2329 (salt-sensitive) and Kharchia65 (salt-tolerant). Kharchia65 can successfully grow in salt affected soils, while HD2329 cannot tolerate salt stress. Differential expression studies of two HKT genes (TaHKT2;1.1 and TaHKT2;3.1) revealed their up-regulated expression (~1.5-fold) in the salt-sensitive HD2329 and down-regulated (~5-fold) inducible expression in the salt-tolerant genotype (Kharchia65). Specific activity of antioxidant enzymes, viz. superoxide dismutase (SOD), peroxidase (POX), ascorbate peroxidase (APX), catalase (CAT) and glutathione reductase (GR) was found to be higher in the salt-tolerant genotype. Isozyme profile of two (POX and GR) antioxidant enzymes showed polymorphism between salt-tolerant and salt-sensitive genotypes. A new gene TaHKT2;3.1 was also identified and its expression profile and role in salt stress tolerance in wheat was also studied. Partial sequences of the TaHKT2;1.1 and TaHKT2;3.1 genes from bread wheat were submitted to the EMBL GenBank database. Our findings indicated that defence responses to salt stress were induced differentially in contrasting bread wheat genotypes which provide evidences for functional correlation between salt stress tolerance and differential biochemical and molecular expression patterns in bread wheat.