Identification of miRNAs linked to peanut nodule functional processes

microRNAs (miRNAs) are non-coding small RNAs that regulate gene expression at post-transcriptional level.Thousands of miRNAs have been identified in legumes, but studies about miRNAs linked to peanut nodulefunctionality are scarce. In this work we analyzed transcriptional changes in peanut nodules to identifymiRNAs involved in functional processes of these organs. We found 32 miRNAs precursors differentiallyexpressed in nodules compared with roots, and predicted the potential targets of their corresponding maturemiRNAs. Among them, 20 belong to 14 conserved miRNAs families and 12 are Arachis hypogaea-specificmiRNAs. Expression levels of 3 miRNAs (ahy-miR399, ahy-miR159 and ahy-miR3508) were confirmedexperimentally by qPCR. We also demonstrated that the expression of these miRNAs was not affected byinoculation of a biocontrol bacterium or a fungal pathogen. The catalogue of differentially expressed miRNAprecursors and the expression of the corresponding mature miRNA potential targets in the nodules of A.hypogaea obtained in this work is a database of strong candidates, including A. hypogaea-specific miRNAs, forthe regulation of the nodule functionality. The analysis of their role in this process will certainly lead to thecharacterization of essential regulators in these particular aeschynomenoid nodules.

Genome-wide development of polymorphic microsatellite markers and their application in peanut breeding program

BACKGROUND: Cultivated peanut (Arachis hypogaea. L) represents one of the most important oil crops in the world. Although much effort has been expended to characterize microsatellites or Simple Sequence Repeats (SSRs) in peanut, the quantity and quality of the markers in breeding applications remain limited. Here, genome-wide SSR characterization and marker development were performed using the recently assembled genome of the cultivar Tifrunner. RESULTS: In total, 512,900 microsatellites were identified from 2556.9-Mb genomic sequences. Based on the flanking sequences of the identified microsatellites, 7757 primer pairs (markers) were designed, and further evaluated in the assembled genomic sequences of the tetraploid Arachis cultivars, Tifrunner and Shitouqi, and the diploid ancestral species, A. duranensis and A. ipaensis. In silico PCR analysis showed that the SSR markers had high amplification efficiency and polymorphism in four Arachis genotypes. Notably, nearly 60% of these markers were single-locus SSRs in tetraploid Arachis species, indicating they are more specific in distinguishing the alleles of the A and B sub-genomes of peanut. In addition, two markers closely related with purple testa color and 27 markers near to FAD2 genes were identified, which could be used for breeding varieties with purple testa and high-oleic acid content, respectively. Moreover, the potential application of these SSR markers in tracking introgressions from Arachis wild relatives was discussed. CONCLUSIONS: This study reported the development of genomic SSRs from assembled genomic sequences of the tetraploid Arachis Tifrunner, which will be useful for diversity analysis, genetic mapping and functional genomics studies in peanut

Methods of cultivation and technical coefficients of peanuts in the Bahian Recôncavo / Métodos de cultivo e coeficientes técnicos do amendoim no Recôncavo Baiano

The objective of this study was to collect information about peanut cultivation methods adopted by family farmers in the Bahian Recôncavo (region that surrounds the bay in the state of Bahia, Brazil), using a specific form and also direct information from farmers. An ethnobotanical survey was carried out in the mesoregion of the Bahian Recôncavo in the following municipalities: Conceição do Almeida, Cruz das Almas, Maragogipe, São Felipe, São Felix, Sapeaçú and Laje (Vale do Jequiriçá), where 60 local farmers answered a nonstructured questionnaire about peanut cultivation. The cultivation system was estimated based on technical coefficients related to peanut cultivation in the area evaluated. The peanut cultivation system is carried out by family farmers from the Bahian Recôncavo who employ outdated practices and do not use the required basic steps. The technical coefficients analyzed show that the cultivation of peanut is an unprofitable activity when considering the high cost of production in this region, even though productivity is higher than in the entire state as well as in the Northeast region. Farmers in the Bahian Recôncavo do not consider the actual production costs of peanuts since they use seeds from previous crops and do not account for the labor costs of family members. There is a lack of active and continuous technical assistance to family farmers, not only in relation to the cultivation system, but also the possibility of other destinations for peanuts produced in the region.(AU)

O objetivo deste estudo foi levantar informações sobre os métodos de cultivo da cultura do amendoim, adotados por agricultores familiares do Recôncavo Baiano, utilizando-se de um formulário específico e de informações diretas dos agricultores. Foi realizado um levantamento etnobotânico nos municípios da mesorregião do Recôncavo Baiano: Conceição do Almeida, Cruz das Almas, Maragogipe, São Felipe, São Félix, Sapeaçú e no município de Laje (Vale do Jequiriçá), onde 60 agricultores foram entrevistados, por meio de um questionário não estruturado, referente ao cultivo do amendoinzeiro no Recôncavo Baiano. A estimativa do sistema de cultivo foi realizada com base em coeficientes técnicos referentes ao cultivo do amendoinzeiro na área de estudo. O sistema de cultivo do amendoim é realizado por agricultores familiares do Recôncavo Baiano utilizando práticas ultrapassadas, destituídas das etapas básicas necessárias. Os coeficientes técnicos analisados demonstram que o cultivo do amendoinzeiro é uma atividade pouco lucrativa ao se levar em consideração o alto custo de produção nessa região, mesmo a produtividade sendo maior quando comparada com a do estado, assim como com a da região Nordeste. Os agricultores do Recôncavo Baiano não consideram os custos de produção real do amendoim, uma vez que utilizam sementes de cultivos anteriores e não contabilizam os custos de mão de obra dos familiares. Falta aos agricultores familiares assistência técnica atuante e continuada, não só com relação ao sistema de cultivo como também com a possibilidade de outras destinações para o amendoim produzido na região.(AU)

Physiological response of seeds of peanut genotypes to water deficiency / Resposta fisiológica de sementes de genótipos de amendoim submetidos a deficiência hídrica

Among the factors that may influence the germination process of seeds, water deficiency is considered the most important. The present study aims to evaluate the physiological response of peanut genotypes to water deficiency. The experiment was conducted in a completely randomized design with four replications in a 12 x 7 factorial scheme with 12 peanut genotypes and seven polyethylene glycol 6000 concentrations corresponding to osmotic potentials of 0.00; -0.10; -0.20; -0.40; -0.60; -0.80 and -1.00 MPa. The data were submitted to analysis of variance and Tukey's test at a 5% probability level and, when significant, to analysis of variance adjusted to a quadratic polynomial curve. The germination percentage, seed vigor evaluated by the speed germination index, mean germination time, root length and root dry matter of some genotypes were affected by the osmotic potentials. Among the genotypes, there is a differential response related to the water deficiency level. In relation to the physiological response of the seeds, the lineages 506, 599, and 870 and the cultivar IAC Tatu-ST have a higher tolerance of water deficit. The peanut genotypes begin to suffer the effects of water deficiency at the osmotic potential of -0.4 MPa

Entre os fatores externos que podem influenciar o processo germinativo das sementes, a deficiência hídrica é considerada o mais importante. Dessa forma, o objetivo do presente trabalho foi avaliar a resposta fisiológica de sementes de genótipos de amendoim submetidos à deficiência hídrica. O experimento foi conduzido em esquema fatorial 12 x 7, tendo como tratamentos sementes de 12 genótipos de amendoim submetidos a sete concentrações de polietilenoglicol 6000, nos potenciais osmóticos correspondentes a 0,00; -0,10; -0,20; -0,40; -0,60; -0,80; -1,00 MPa. Constatou-se que os genótipos são afetados pelos potenciais osmóticos e, entre os genótipos, há resposta diferenciada em relação ao nível de deficiência hídrica. Em relação à resposta fisiológica das sementes, as linhagens 506, 599, 870 e a cultivar IAC Tatu-ST possuem maiortolerância à deficiência hídrica. Todos os genótipos de amendoim começam a sofrerem os efeitos da deficiência hídrica a partir do potencial osmótico de -0,4 MPa para a maior parte das características avaliadas

Breeding on a new peanut variety Yuhua91 with high oleic acid content / 生物工程学报

Yuhua91 is a new peanut variety with high oleic acid content bred by Qingdao Agricultural University. The crossing was conducted with Luhua11 as female parent and with Kainong1715, an F435-type variety with high oleic acid content as male parent. The real F1 hybrids were screened by sequencing on PCR amplification products, and those homozygotes with bb genotype in F2 populations were screened by the same sequencing method as above. The content of oleic and linoleic acid was measured on the kernels harvested from F2 single plants by near infrared ray method, and those kernels whose content of oleic was above 80%, oleic and linoleic acid ratio was above 10.0 were obtained and planted into a row, with pedigree method for subsequent selection breeding. Yuhua91 has some characters of small pod, light and obvious pod texture, 148.06 g per 100 pods, 63.31 g per 100 kernels, 75.15% shelling percentage, long elliptic seed kernel, pink seed coat, without crack, white endotesta. Its content of protein, oil, oleic acid, linoleic acid and palmitic acid was 26.57%, 52.72%, 80.40%, 2.50% and 5.57% respectively. Yuhua91 has other characters of strong seedlings, compact pod areas, and moderate resistance to leaf spot disease and bacterial wilt. Average pod yield is 215.79 kg per Mu, 15.27% higher than the control variety Huayu20. Average seed kernels yield is 157.33 kg per Mu, 21.64% higher than the control variety Huayu20. Yuhua 91 has been registered on department of agriculture in 2018, and the registration No. is GPD peanut (2018) 370210, fit for growing in Shandong Province.

Transcriptome profiling and digital gene expression analysis of genes associated with salinity resistance in peanut

Background: Soil salinity can significantly reduce crop production, but the molecular mechanism of salinity tolerance in peanut is poorly understood. A mutant (S1) with higher salinity resistance than its mutagenic parent HY22 (S3) was obtained. Transcriptome sequencing and digital gene expression (DGE) analysis were performed with leaves of S1 and S3 before and after plants were irrigated with 250 mM NaCl. Results: A total of 107,725 comprehensive transcripts were assembled into 67,738 unigenes using TIGR Gene Indices clustering tools (TGICL). All unigenes were searched against the euKaryotic Ortholog Groups (KOG), gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases, and these unigenes were assigned to 26 functional KOG categories, 56 GO terms, 32 KEGG groups, respectively. In total 112 differentially expressed genes (DEGs) between S1 and S3 after salinity stress were screened, among them, 86 were responsive to salinity stress in S1 and/or S3. These 86 DEGs included genes that encoded the following kinds of proteins that are known to be involved in resistance to salinity stress: late embryogenesis abundant proteins (LEAs), major intrinsic proteins (MIPs) or aquaporins, metallothioneins (MTs), lipid transfer protein (LTP), calcineurin B-like protein-interacting protein kinases (CIPKs), 9-cis-epoxycarotenoid dioxygenase (NCED) and oleosins, etc. Of these 86 DEGs, 18 could not be matched with known proteins. Conclusion: The results from this study will be useful for further research on the mechanism of salinity resistance and will provide a useful gene resource for the variety breeding of salinity resistance in peanut.

Analysis of the peanut transgenic offspring with depressing AhFAD2 gene / 生物工程学报

The delta-12 fatty acid desaturase (Δ¹² FAD or FAD2) is a key enzyme that catalyzes oleic acid to linoleic acid by dehydrogenation at Δ¹² position of fatty acid carbon chain. In peanut, reduction or loss of FAD2 activity could enhance the relative content of oleic acid in kernels, and improve the quality and oxidation stability of peanut kernels and products. RNA interference (RNAi) technology could lead to non-expression or down-regulated expression of AhFAD2 gene. We constructed two RNA interference expression vectors with the inverted repeat sequence of partial AhFAD2 gene, which were driven separately by cauliflower mosaic virus (CaMV) 35S promoter or soybean agglutinin lectin seed-specific promoter. Homozygous transgenic lines carrying the two constructs stably in genetics were developed by peanut genetic transformation. There were no significant differences between the transgenic lines and the control through investigating the main agronomic traits. We analyzed the transcriptional level expression of AhFAD2 gene in transgenic lines and the control by real-time fluorescence quantitative PCR (qRT-PCR). The results suggested that the target genes of transgenic lines were likely suppressed by RNA interference, but showed different transcriptional levels in different peanut transgenic lines. Compared with untransformed lines, the resulting down-regulation of AhFAD2 gene resulted in a 15.09% or 36.40% increase in oleic acid content in the seeds of transformed HY23 and FH1 lines respectively, and the content of linoleic acid decreased by 16.19% or 29.81%, correspondingly, the ratio of oleic acid and linoleic acid (O/L) improved by 38.02%, 98.10%. The oleic acid content had significant differences between the two transformation constructs, and also among different transgenic lines. Moreover, the inhibition effect of RNAi was more obvious in the transgenic lines with FH1 as the receptor, and with transformation structure driven by seed specific promoter. The suppressed expression of AhFAD2 gene enabled the development of peanut fatty acid, which indicated that RNA interference would be a reliable technique for the genetic modification of peanut seed quality and the potential for improvement of other traits as well.

Ethnobotany of the peanut in recôncavo da Bahia, Brazil / Etnobotânica do amendoim no recôncavo da Bahia, Brasil

The aim of this study was to perform an ethnobotanical survey in some regions of Recôncavo da Bahia, Brazil, to investigate the profile of farmers and the local knowledge about Arachis hypogaea L. (peanut). We sampled 60 local peanut farmers from rural areas in the municipalities Conceição do Almeida, Cruz das Almas, Maragogipe, São Felipe, São Félix, Sapeaçú and Lage. One producer per residence was interviewed and a semi-structured interview model was used. During the interviews, seeds stored by the producers were collected for future analysis. The frequency of the answers was calculated using SAS (Statistical analysis system) software. Using an ethnobotanical approach, we were able to show that peanut cultivation is part of the Recôncavo da Bahia culture and that farmers in the area have their own knowledge about the use and management of this crop. This knowledge arose from information passed down over the years from previous generations. Similar farming techniques were used in all of the studied municipalities.

Objetivou-se realizar um levantamento etnobotânico em alguns municípios do Recôncavo da Bahia visando uma investigação sobre o perfil dos agricultores, além da caracterização do conhecimento local sobre a espécie. Foram feitas visitas a 60 produtores residentes em comunidades da zona rural dos municípios de Conceição do Almeida, Cruz das Almas, Maragogipe, São Felipe, São Félix, Sapeaçú e Lage, que têm contato direto com a cultura do amendoim, sendo entrevistada uma pessoa por domicílio, e que cultiva o amendoim. Utilizou-se um modelo de entrevista semiestruturada. No momento das entrevistas, foram realizadas as coletas de sementes armazenadas pelos produtores para serem testadas em trabalhos futuros. Foi calculada a frequência percentual de acordo com as respostas dos agricultores com auxílio do programa estatístico SAS - Statistical Analysis System. Por meio do levantamento etnobotânico, fica claro que o amendoim faz parte da cultura do Recôncavo da Bahia e que os agricultores detêm conhecimentos próprios sobre as formas de uso e manejo da cultura, oriundos de informações repassadas ao longo dos anos, vindas de gerações anteriores, levando-os a utilizarem técnicas de cultivo parecidas em todos os municípios que contribuíram com a pesquisa.

Análise do extrato aquoso de Arachis hipoagea L. no combate à dislipidemia e ao ganho ponderal de ratos Wistar submetidos à dieta hiperlipídica / Analysis of the aqueous extract of Arachis hipoagea L. to reduce dyslipidemia and weight gain in Wistar rats with high fat diet

O objetivo desse estudo foi avaliar os efeitos do Extrato Aquoso de Amendoim (EAA) no peso, bioquímica sérica e na histologia hepática de ratos Wistar submetidos a dietas normo e hiperlipídicas. A pesquisa foi realizada utilizando 40 ratos Wistar machos, divididos em quatro grupos (n=10): GA (dieta hiperlipídica), GB (dieta hiperlipídica +EAA), GC (dieta normolipídica) e GD (dieta normolipídica +EAA). Após 8 semanas, os animais foram eutanasiados e foram coletadas amostras sanguíneas para a avaliação de dados bioquímicos (Colesterol total e suas frações, triglicerídeos, uréia, creatinina, AST, ALT e glicemia) e fragmentos do fígado para análise histológica. Os animais do grupo GB tiveram um ganho de peso inferior quando comparados ao GA (XGB= versus XGA= p<0,05), já os grupos GC e GD não obtiveram diferenças estatísticas. Os animais que receberam o EAA tiveram uma redução nos níveis de colesterol (XGB= versus XGA= p<0,05 e XGD= versus XGA= p<0,01), dos triglicerídeos (XGB= versus XGA e XGD= versus XGA= p<0,001) e mais discretamente dos níveis de ALT. A glicemia, uréia e creatina permaneceram dentro dos valores de referência. As amostras hepáticas analisadas, dos ratos dos diferentes grupos, não apresentaram alterações histopatológicas. Conclui-se que O EAA apresentou efeitos preventivos sobre o ganho ponderal e dislipidemia.(AU)

The aim of this study was to evaluate the effect of Aqueous Extract from Peanut (EAA) in weight, serum biochemistry and liver histology of Wistar rats with normal hearing and a high fat diet. The survey was conducted using 40 male Wistar rats divided into four groups (n=0): GA (high fat diet), GB (fat diet+EAA), GC (normolipídica diet), and GD (normolipídica diet+EAA). After 8 weeks, the rats were euthanized and blood samples were collected to evaluate biochemical data (total cholesterol and its fractions, triglycerides, urea, creatinine, AST, ALT and glucose) and liver fragments for histological analysis. The animals of the GB group had a lower weight gain when compared with GA (XGB versus XGA= p<0.05), but CG and GD did not obtain statistical differences. The rats that received EAA had a reduction in cholesterol levels (XGB= versus XGA= p<0.05 vs. XGA and XGD= p<0.01), triglycerides (=XGB versus XGA and =XGD versus XGA= p<0,001) and more discreetly ALT levels. Blood glucose, urea and creatine remained within the reference values. Liver samples analyzed, the rats of different groups showed no histopathological changes. In conclusion, the EAA had preventive effects on weight gain and dyslipidemia.(AU)

Isolation and identification of the chemical constituents from stems and leaves of Arachis hypogaea L / 中国药学杂志

OBJECTIVE: To study the chemical constituents from the stems and leaves of Arachis hypogaea L. METHODS: Various column chromatographic techniques were used to separate and purify the chemical constituents and their structures were elucidated by spectral analysis. RESULTS: Fifteen compounds were isolated and identified as 4,9-dihydroxy-3-methothxy-coumestan(I), 3-hydroxy-9-dimethothxycoumestan (II), 3-isopropyl-pyrrolopiperazine-2,5-dione(III), 3-isobutylpyrrol-opiperazine-2,5-dione(IV), uracil(V), thymine(VI), thymidine(VH), L-(-)-phenylalanine(VI), nicotinic acid(IX), 2-furancarboxylic acid(X), ferulic acid (XI), vanillic acid(XII), 2-hydroxybenzoic acid(XIII), amber acid(XIV), and methyl hydrogen succinate(XV). CONCLUSION: The compounds I-IX are isolated from Arachis hypogaea L. for the first time.

Fenologia e produtividade do amendoim em diferentes épocas de semeadura no recôncavo sul baiano / Phenology and yield of peanut in different sowing seasons in southern bahia recôncavo

O trabalho foi feito com o objetivo de avaliar a fenologia e a produtividade de duas cultivares de amendoim (Arachis hypogaea L.) em diferentes épocas de semeadura na região do Recôncavo sul Baiano. A primeira época de semeadura foi julho-outubro e a segunda abril-julho. Para cada época, foi instalado um experimento no delineamento em blocos casualizados no esquema fatorial 2 x 2 (cultivares x época) com quatro repetições, em parcelas de 5,0 m de comprimento e largura de 4,0 m, constituídas de oito linhas cada, nas quais foram observados, a cada três dias, os estádios de desenvolvimento das plantas das cultivares Vargem Lisa e BRS Havana. Avaliou-se a fenologia (germinação, aparecimento das primeiras folhas tetrafoliadas, aparecimento dos primeiros ramos, início da floração, aparecimento do ginóforo, início da formação da vagem, final da floração e maturação completa da vagem) e a produtividade de vagens e grãos (kg ha-1). A época de semeadura e a cultivar influenciam diretamente na fenologia das plantas de amendoim. A cultivar Vagem Lisa teve um maior rendimento de vagens e grãos na segunda época de semeadura.

The goal of this research was to assess the phenology and productivity of two peanut cultivars (Arachis hypogaea L.) in different sowing seasons in the region of southern Bahia Recôncavo. The first sowing season was from July to October and the second season from April to July. For each season, an experiment was conducted carried out in randomized block design in a factorial scheme 2 x 2 (cultivars x sowing season) with four replicates. Each in plot was consisted of eight lines with 5.0 m in length and 4.0 m in width. The assessments were done every three days during the plant development stages of Vargem Lisa and BRS Havana cultivars. We evaluated the phenology (germination, emergence of first leaves tetrafoliadas, onset of the first branches, beginning of flowering, emergence of gynophore, beginning of pod formation, ending of flowering and full pod maturity) and yield of pods and grains (kg h-1). The sowing season and cultivar directly influence the peanut phenology. The cultivar Vagem Lisa had a highergreater pod lat and grain yield in the second sowing season planting.

Physiological studies of Arachis Hypogaea L. under the influence of sulfosalicylic acid.

A study was carried out on growth, photosynthetic pigments, and yield attributing and seed characteristics of Arachis hypogaea L. (Cv. SB-11). The treatments comprised of different concentrations (5, 50, 100 and 200 ppm) of Sulfosalicylic acid (SSA). The results showed that 50 ppm concentration of foliar applied SSA effectively promoted the growth parameters, photosynthetic pigments (chl a, chl b, total chl, carotenoids and chlorophyll stability index), yield parameters and seed protein and seed oil contents of groundnut. Similarly significant decrease in severity of tikka disease was reported with 50 ppm SSA. SSA 100 ppm profound better influence on the number of branches, height of plant and the shelling percentage. It could be concluded that SSA proved to be beneficial in promoting plant growth and yield and in inducing systemic resistance against tikka disease in groundnut.

Radio-Sensitivity of Some Groundnut (Arachis hypogaea L.) Genotypes to Gamma Irradiation: Indices for Use as Improvement.

Mutation breeding in crop plants is an effective approach in improvement of crop having narrow genetic base such as groundnuts (Arachis hypogaea L.). Determination of effective irradiation dose is prerequisite for mutation breeding and development of genetic variability by induced mutation. Three groundnuts (Arachis hypogaea L.) genotypes (JL12, JL24 and Kimpese) were irradiated to the absorbed doses of 100, 200, 400 and 600 Gy for effective dose determination and to compare their sensitivity to different doses of gamma irradiation in a completely random design. It was found that, irradiation reduced significantly germination and survival percentages of seedlings in higher doses and this reduction was more pronounced in JL 24 cultivar. This sensitivity expresses himself distinctly to the rank of stem lengths and roots. Results show a negative interrelationship indeed between doses of irradiation applied and lengths of stems and roots. With attention to LD50 data, our results indicated that optimum doses were 200 Gy for JL12 and Kimpese, and 100 Gy for JL24. We concluded that JL24 are more sensitive to gamma irradiation than JL12 and Kimpese.

Chance matemática na determinação do estado nutricional do amendoim / Mathematical chance in determination of nutritional status of peanut

Na literatura, são escassas informações a cerca da avaliação nutricional para a maioria das culturas, em especial o amendoim. Objetivou-se avaliar o estado nutricional do amendoim cultivar BR-1, através da chance matemática. O experimento foi conduzido em Fortaleza-CE, no período de agosto a dezembro de 2009. As plantas foram cultivadas em canteiros, adubados com N (3, 21, 30, 39 e 57 kg ha-1), P2O5 (7, 46, 65, 85 e 124 kg ha-1) e K2O (5, 32, 45, 59 e 86 kg ha-1), sendo composto por dezesseis tratamentos conforme a matriz Plan Puebla III e quatro repetições. Durante o período de florescimento foi coletada folhas para a determinação dos teores de NPK. Utilizou-se a ChM matemática para fazer a diagnose foliar. Para N, as maiores chances matemáticas para obtenção de altas produtividades ocorreram com teores de N na faixa de 31,11 a 40,23 g kg-1, para P, de 1,66 a 2,11 g kg-1 e para K entre 13,42 a 18,15 g kg-1. Pela ChM, estimou-se que os teores de 35,67; 1,89 e 15,78 g kg -1 de N; P e K, respectivamente, como sendo os teores ótimos para a cultura. O método mostra-se promissor para determinar a faixa de suficiência e nível crítico para a cultura do amendoim cultivar BR-1.

In the literature, there is little information about the nutritional assessment for most crops, especially peanut. Therefore, the objective of this study was to evaluate the nutritional status of the peanut cultivar BR-1, by the method of mathematical chance (ChM). The experiment was conducted in Fortaleza-CE, from August to December 2009. Plants were grown in beds, fertilized with N (3, 21, 30, 39 and 57 kg ha-1), P2O5 (7, 46, 65, 85 and 124 kg ha-1) and K2O (5, 32, 45, 59 e 86 kg ha-1), comprising sixteen treatment as the matrix Plan Puebla III, with four replications. During the flowering period leaves were collected to determine the levels of NPK. The method of mathematical chance was used to make the leaf diagnosis. The greatest mathematical chance to obtain high yields occurred at contents from 31.11 to 40.23 g kg-1 for N; 1.66 to 2.11 g kg-1 for P and 13.42 to 18.15 g kg-1 for K. By the method of ChM, it was estimated that the levels of 35.67, 1.89 and 15.78 g kg-1 of N, P and K, respectively, were the optimum levels for the crop. The method shows promise for determining the sufficiency range and critical level for the peanut crop cultivar BR-1.

Cloning and expression analysis of peanut (Arachis hypogaea L. ) CHI gene

Chalcone isomerase (CHI) is the key enzyme that catalyzes chalcone into (2S)-flavanol or (2S)-5-desoxidation flavanol. The full length cDNA (1050 bp) of AhCHI (Arachis hypogaea CHI gene) was cloned by large scale EST sequencing using a peanut immature seed cDNA library. Sequence analysis results indicated that it was a type I CHI gene (with the accession number JN660794). The ORF of AhCHI was 768 bp, encoding a peptide of 255 amino acids with a pI of 5.189. Sequence alignment showed that the coding region of AhCHI gene is highly conserved to compare with CHI genes from other plant species. Peanut cDNA microarray and semi-quantitative RT-PCR analysis indicated that AhCHI was highly expressed in pegs. The expression level in flower and root was higher than the expression level in stem and leaf. AhCHI was expressed in a high level in seeds with a purple seed coat, while its expression was low in seed with white seed coat.

Características de deficiência nutricional do amendoinzeiro submetido à omissão de N, P, K / Characteristics of nutritional deficiency in groundnut submitted to the absence of N, P, and K

O amendoim é uma excelente alternativa agrícola para a região Nordeste do Brasil, porém, poucos estudos têm sido realizados para esta cultura, no tocante à sua adubação. Sendo assim, foi realizado um estudo com o objetivo de avaliar o rendimento e as características visuais de deficiência nutricional do amendoinzeiro (Arachis hypogaea L.) submetido à omissão de N, P e K. O experimento foi realizado em casa de vegetação da Universidade Federal do Recôncavo da Bahia, no Centro de Ciências Agrárias, Ambientais e Biológicas, situada em Cruz das Almas ­ BA, no período de Agosto a Outubro de 2010. O delineamento experimental foi em blocos casualizados, constando de sete tratamentos e quatro repetições. Os tratamentos estudados foram: T1- Solução Completa; T2- Omissão de N; T3- Omissão de P; T4 - Omissão K; T5- Omissão de NP; T6- Omissão PK e T7- Omissão de NPK. Durante todo o ciclo da cultura avaliou-se os possíveis aspectos visuais de deficiência. Ao final do experimento foram avaliados dados de altura e teor de clorofila. Aos 60 dias após a emergência, as plantas foram coletadas e particionadas em folhas, hastes e raízes, e secadas a 65ºC em estufa com circulação forçada de ar até atingir peso constante para quantificar a massa seca da parte aérea e da raiz. Nestas condições experimentais a omissão de K não se mostrou um fator limitante para o acúmulo de massa seca de folhas e haste nas plantas de amendoim. O fósforo se mostrou bastante requerido para o crescimento em altura e acúmulo de massa seca das folhas e hastes. O teor de clorofila da planta foi menor nos tratamento onde houve a omissão de N. Dos tratamentos aplicados, o que se mostrou mais limitante foi o tratamento com omissão de NPK, confirmando a importância da aplicação destes nutrientes às plantas de amendoim.

The groundnut is a great agricultural alternative for the Northeast region of Brazil, but few studies have been carried out for this crop in relation to its fertilization. Thus, a study was conducted to evaluate the performance and visual characteristics of nutritional deficiency in groundnut (Arachis hypogaea L.) submitted to the absence of N, P, and K. The experiment was conducted in a greenhouse at the Federal University of Bahia Recôncavo, at the Center for Agricultural, Environmental and Biological Sciences, located in Cruz das Almas, BA, from August to October 2010. The experimental design was in randomized blocks, consisting of seven treatments and four replications. The treatments were: T1 - Complete Solution; T2 - Omission of N; T3 - Omission of P; T4 - Omission of K; T5 - Omission of NP; T6 ­ Omission of PK; and T7 - Omission of NPK. Throughout the crop cycle possible visual aspects of deficiency were assessed. At the end of the experiment, the data were evaluated in height and chlorophyll content. At sixty days after emergence (DAE) plants were collected and partitioned into leaves, stem and root for drying in air forced oven at 65°C until constant weight was obtained to measure the dry mass of shoot and root. Under these experimental conditions the omission of K was not a limiting factor for dry mass of leaves and stem in peanut plants. Phosphorus is an element that proved to be enough for the required growth in height and accumulation of dry mass of leaves and stem. The chlorophyll content of the plant was lower in the treatment in which there was the omission of N. The treatment with omission of NPK was the most limiting, demonstrating the importance of applying these nutrients to the groundnut plants.

Condutividade elétrica em função do teor de água inicial de sementes de amendoim / Electrical conductivity and water content in peanut seeds

O vigor de sementes de amendoim (Arachis hypogaea L.) avaliado pelo teste de condutividade elétrica demonstra estreita relação com o desempenho no campo, mas alguns fatores podem afetar o resultado da condutividade elétrica, sendo um destes o teor de água inicial das sementes. Assim, o objetivo deste trabalho foi avaliar o teor de água ou faixa de umidade da semente mais adequado para a avaliação da condutividade elétrica em sementes de amendoim. Quatro lotes de sementes da cultivar 'IAC Tatu ST' e quatro da cultivar 'IAC Runner 886' foram avaliados quanto ao seu potencial fisiológico e posteriormente o teor de água foi ajustado para 5, 7, 9, 11, 13 e 15 por cento, pelo método da atmosfera úmida. O delineamento foi inteiramente casualizado em esquema fatorial 4×6 (lotes × teores de água) para as sementes de cada cultivar, em quatro repetições e os resultados para o fator teor de água foram submetidos à análise de regressão. A maior relação da condutividade elétrica com vigor das sementes ocorreu naquelas com teor de água entre 9 a 15 por cento, de forma que sementes com 5 a 7 por cento de umidade não devem ser submetidas ao teste de condutividade elétrica, porque os lotes expressam alto padrão de germinação e vigor. A condutividade elétrica de sementes de amendoim é influenciada pelo teor de água e a estabilização dos resultados ocorre quando elas estão com teor de água entre 10 e 14 por cento.

The vigor of peanut seeds (Arachis hypogaea L.) assessed by the conductivity test shows close relationship with performance in the field, but some factors may affect the outcome of the electrical conductivity, being one of that the initial water content of seeds. The objective of this study was to evaluate the seed water content most appropriate for evaluating the seed vigor through electrical conductivity test in peanut. Four seed lots of 'IAC Tatu ST' cultivar and four 'IAC Runner 886' were initially evaluated for their physiological potential and subsequently the seed water content was adjusted to 5, 7, 9, 11, 13 and 15 percent by the method of controlled atmosphere. A completely randomized design with treatments arranged in a 4×6 factorial design (seed lots × seed water content levels) for each cultivar and four replications were used. The results for the factor seed water content were subjected to the analysis regression. The higher relationship of electrical conductivity and seed vigor occurred when the seed lots presents seed moisture content varying from 9 to 15 percent. Seeds with 5-7 percent moisture should not be subjected to electrical conductivity test, because lots express high standard germination and vigor. The electrical conductivity of peanut seeds is influenced by the seed moisture content and the stabilization of the results occurs when the seeds have moisture content between 10 and 14 percent.

Isolation and expression analysis of LEA genes in peanut (Arachis hypogaea L.).

Late embryogenesis abundant (LEA) protein family is a large protein family that includes proteins accumulated at late stages of seed development or in vegetative tissues in response to drought, salinity, cold stress and exogenous application of abscisic acid. In order to isolate peanut genes, an expressed sequence tag (EST) sequencing project was carried out using a peanut seed cDNA library. From 6258 ESTs, 19 LEA-encoding genes were identified and could be classified into eight distinct groups. Expression of these genes in seeds at different developmental stages and in various peanut tissues was analysed by semi-quantitative RT-PCR. The results showed that expression levels of LEA genes were generally high in seeds. Some LEA protein genes were expressed at a high level in non-seed tissues such as root, stem, leaf, flower and gynophore. These results provided valuable information for the functional and regulatory studies on peanut LEA genes.

A real-time PCR genotyping assay to detect FAD2A SNPs in peanuts (Arachis hypogaea L)

The high oleic (C18:1) phenotype in peanuts has been previously demonstrated to result from a homozygous recessive genotype (ol1ol1ol2ol2) in two homeologous fatty acid desaturase genes (FAD2A and FAD2B) with two key SNPs. These mutant SNPs, specifically G448A in FAD2A and 442insA in FAD2B, significantly limit the normal function of the desaturase enzyme activity which converts oleic acid into linoleic acid by the addition of a second double bond in the hydrocarbon chain. Previously, a genotyping assay was developed to detect wild type and mutant alleles in FAD2B. A real-time PCR assay has now been developed to detect wild type and mutant alleles (G448A) in FAD2A using either seed or leaf tissue. This assay was demonstrated to be applicable for the detection of homozygous and heterozygous samples. The FAD2A genotyping assay was validated by employing gas chromatography (GC) to determine total fatty acid composition and by genotyping peanut lines that have been well characterized. Overall, development of rapid assays such as real-time PCR which can identify key genotypes associated with important agronomic traits such as oleic acid, will improve breeding efficiency by targeting desirable genotypes at early stages of development.

Effect of weeding frequencies and plant density on the vegetative growth characteristic in groundnut (Arachis hypogaea L.) in north Kordofan of Sudan.

Weeds play an important role in the proper stand establishment of the growing crop, which ultimately affect the productivity and quality at the end of the growing season. A Field experiment conducted at North Kordofan of Sudan, on naturally infested fields during 2006/07 and 2007/08 seasons, to determine optimal weeding frequency for weeding management in four plant density (17, 1 1, 8 and 7 plants m-2) of groundnut (Arachis hypogaea L). Weeding treatments consisted of three levels (no weeding, weeding once (at 15 days) and weeding twice (at 15 and 30 days after sowing). The weeds were controlled using a hand hoe. The dominant weed species were Cenchrus biflorus L, Zornia glochidiata L and Trienemara pentanture L. Weeds significantly reduced the vegetative growth attributes measured. Weeding twice at 15 and 30 days after sowing was optimal for plant height, branches, nodes number and leaf area index. High vegetative growth performance obtained at population of 17 plants m-2.