Phytoparasitic Nematodes of Musa spp. with Emphasis on Sources of Genetic Resistance: A Systematic Review.

Bananas are a staple food that considerably contributes to both food security and income generation, especially in countries of Africa, Asia, and Central and South America. The banana plant (Musa spp.) is affected by various pathogens, of main concern being the plant-parasitic nematodes associated with the rhizosphere, the most important of which are Radopholus similis (burrowing nematode), Helicotylenchus sp. (spiral nematode), Pratylenchus sp. (root lesion nematode), and Meloidogyne sp. (gall nematode). Infected plants reduce their ability to absorb water and nutrients, which can lead to delayed flowering, fewer bunches, and lower fruit mass. Obtaining nematode-resistant banana cultivars through genetic improvement is an effective and sustainable option compared with chemical control with nematicides. Here, we provide the first systematic review of existing banana sources of resistance to nematodes to aid the management and control of nematodes in banana and plantain crops. Articles selected from different databases were evaluated, and searches were conducted using pre-established inclusion and exclusion criteria. We found 69 studies dealing with genetic improvement for nematode resistance in banana cultivation. Our findings revealed that sources of resistance are currently under investigation to combat the diseases caused by different nematode species in banana plants.

Characterization of microRNAs and Target Genes in Musa acuminata subsp. burmannicoides, var. Calcutta 4 during Interaction with Pseudocercospora musae.

Endogenous microRNAs (miRNAs) are small non-coding RNAs that perform post-transcriptional regulatory roles across diverse cellular processes, including defence responses to biotic stresses. Pseudocercospora musae, the causal agent of Sigatoka leaf spot disease in banana (Musa spp.), is an important fungal pathogen of the plant. Illumina HiSeq 2500 sequencing of small RNA libraries derived from leaf material in Musa acuminata subsp. burmannicoides, var. Calcutta 4 (resistant) after inoculation with fungal conidiospores and equivalent non-inoculated controls revealed 202 conserved miRNAs from 30 miR-families together with 24 predicted novel miRNAs. Conserved members included those from families miRNA156, miRNA166, miRNA171, miRNA396, miRNA167, miRNA172, miRNA160, miRNA164, miRNA168, miRNA159, miRNA169, miRNA393, miRNA535, miRNA482, miRNA2118, and miRNA397, all known to be involved in plant immune responses. Gene ontology (GO) analysis of gene targets indicated molecular activity terms related to defence responses that included nucleotide binding, oxidoreductase activity, and protein kinase activity. Biological process terms associated with defence included response to hormone and response to oxidative stress. DNA binding and transcription factor activity also indicated the involvement of miRNA target genes in the regulation of gene expression during defence responses. sRNA-seq expression data for miRNAs and RNAseq data for target genes were validated using stem-loop quantitative real-time PCR (qRT-PCR). For the 11 conserved miRNAs selected based on family abundance and known involvement in plant defence responses, the data revealed a frequent negative correlation of expression between miRNAs and target host genes. This examination provides novel information on miRNA-mediated host defence responses, applicable in genetic engineering for the control of Sigatoka leaf spot disease.

Gene Editing for Plant Resistance to Abiotic Factors: A Systematic Review.

Agricultural crops are exposed to various abiotic stresses, such as salinity, water deficits, temperature extremes, floods, radiation, and metal toxicity. To overcome these challenges, breeding programs seek to improve methods and techniques. Gene editing by Clustered Regularly Interspaced Short Palindromic Repeats-CRISPR/Cas-is a versatile tool for editing in all layers of the central dogma with focus on the development of cultivars of plants resistant or tolerant to multiple biotic or abiotic stresses. This systematic review (SR) brings new contributions to the study of the use of CRISPR/Cas in gene editing for tolerance to abiotic stress in plants. Articles deposited in different electronic databases, using a search string and predefined inclusion and exclusion criteria, were evaluated. This SR demonstrates that the CRISPR/Cas system has been applied to several plant species to promote tolerance to the main abiotic stresses. Among the most studied crops are rice and Arabidopsis thaliana, an important staple food for the population, and a model plant in genetics/biotechnology, respectively, and more recently tomato, whose number of studies has increased since 2021. Most studies were conducted in Asia, specifically in China. The Cas9 enzyme is used in most articles, and only Cas12a is used as an additional gene editing tool in plants. Ribonucleoproteins (RNPs) have emerged as a DNA-free strategy for genome editing without exogenous DNA. This SR also identifies several genes edited by CRISPR/Cas, and it also shows that plant responses to stress factors are mediated by many complex-signaling pathways. In addition, the quality of the articles included in this SR was validated by a risk of bias analysis. The information gathered in this SR helps to understand the current state of CRISPR/Cas in the editing of genes and noncoding sequences, which plays a key role in the regulation of various biological processes and the tolerance to multiple abiotic stresses, with potential for use in plant genetic improvement programs.

Transcriptome Profiling of the Resistance Response of Musa acuminata subsp. burmannicoides, var. Calcutta 4 to Pseudocercospora musae.

Banana (Musa spp.), which is one of the world's most popular and most traded fruits, is highly susceptible to pests and diseases. Pseudocercospora musae, responsible for Sigatoka leaf spot disease, is a principal fungal pathogen of Musa spp., resulting in serious economic damage to cultivars in the Cavendish subgroup. The aim of this study was to characterize genetic components of the early immune response to P. musae in Musa acuminata subsp. burmannicoides, var. Calcutta 4, a resistant wild diploid. Leaf RNA samples were extracted from Calcutta 4 three days after inoculation with fungal conidiospores, with paired-end sequencing conducted in inoculated and non-inoculated controls using lllumina HiSeq 4000 technology. Following mapping to the reference M. acuminata ssp. malaccensis var. Pahang genome, differentially expressed genes (DEGs) were identified and expression representation analyzed on the basis of gene ontology enrichment, Kyoto Encyclopedia of Genes and Genomes orthology and MapMan pathway analysis. Sequence data mapped to 29,757 gene transcript models in the reference Musa genome. A total of 1073 DEGs were identified in pathogen-inoculated cDNA libraries, in comparison to non-inoculated controls, with 32% overexpressed. GO enrichment analysis revealed common assignment to terms that included chitin binding, chitinase activity, pattern binding, oxidoreductase activity and transcription factor (TF) activity. Allocation to KEGG pathways revealed DEGs associated with environmental information processing, signaling, biosynthesis of secondary metabolites, and metabolism of terpenoids and polyketides. With 144 up-regulated DEGs potentially involved in biotic stress response pathways, including genes involved in cell wall reinforcement, PTI responses, TF regulation, phytohormone signaling and secondary metabolism, data demonstrated diverse early-stage defense responses to P. musae. With increased understanding of the defense responses occurring during the incompatible interaction in resistant Calcutta 4, these data are appropriate for the development of effective disease management approaches based on genetic improvement through introgression of candidate genes in superior cultivars.

Molecular, Histological and Histochemical Responses of Banana Cultivars Challenged with Fusarium oxysporum f. sp. cubense with Different Levels of Virulence.

Fusarium wilt caused by Fusarium oxysporum f. sp. cubense (Foc) is the most limiting factor in the banana agribusiness worldwide. Therefore, studies regarding pathogen attack mechanisms, and especially host defense responses, in this pathosystem are of utmost importance for genetic breeding programs in the development of Foc-resistant banana cultivars. In this study, analysis at the molecular, histological and histochemical levels of the Musa spp. x Foc interaction was performed. Three Foc isolates representative of race 1 (R1), subtropical race 4 (ST4) and isolate 229A, which is a putative ST4, were inoculated in two Prata-type cultivars (Prata-Anã and BRS Platina) and one cultivar of the Cavendish type (Grand Naine). Of seven genes related to plant-pathogen interactions, five were overexpressed in 'BRS Platina' 12 h after inoculation (HAI) with Foc R1 and ST4 but had reduced or negative expression after inoculation with Foc 229A, according to RT-qPCR analyses. While hyphae, mycelia and spores of the Foc 229A isolate grow towards the central cylinder of the Grand Naine and Prata-Anã cultivars, culminating in the occlusion of the xylem vessels, the BRS Platina cultivar responds with increased presence of cellulose, phenolic compounds and calcium oxalate crystals, reducing colonization within 30 days after inoculation (DAI). In general, these data indicate that the cultivar BRS Platina has potential for use in banana-breeding programs focused on resistance to Foc tropical race 4 (TR4) and in aggregating information on the virulence relationships of the Foc pathogen and the defense responses of banana plants after infection.

Gene Expression, Histology and Histochemistry in the Interaction between Musa sp. and Pseudocercospora fijiensis.

Bananas are the main fruits responsible for feeding more than 500 million people in tropical and subtropical countries. Black Sigatoka, caused by the fungus Pseudocercospora fijiensis, is one of the most destructive disease for the crop. This fungus is mainly controlled with the use of fungicides; however, in addition to being harmful to human health, they are associated with a high cost. The development of resistant cultivars through crosses of susceptible commercial cultivars is one of the main focuses of banana breeding programs worldwide. Thus, the objective of the present study was to investigate the interaction between Musa sp. and P. fijiensis through the relative expression of candidate genes involved in the defence response to black Sigatoka in four contrasting genotypes (resistant: Calcutta 4 and Krasan Saichon; susceptible: Grand Naine and Akondro Mainty) using quantitative real-time PCR (RT-qPCR) in addition to histological and histochemical analyses to verify the defence mechanisms activated during the interaction. Differentially expressed genes (DEGs) related to the jasmonic acid and ethylene signalling pathway, GDSL-like lipases and pathogenesis-related proteins (PR-4), were identified. The number and distance between stomata were directly related to the resistance/susceptibility of each genotype. Histochemical tests showed the production of phenolic compounds and callosis as defence mechanisms activated by the resistant genotypes during the interaction process. Scanning electron microscopy (SEM) showed pathogenic structures on the leaf surface in addition to calcium oxalate crystals. The resistant genotype Krasan Saichon stood out in the analyses and has potential for use in breeding programs for resistance to black Sigatoka in banana and plantains.

Morphoanatomy and Histochemistry of Septal Nectaries Related to Female Fertility in Banana Plants of the 'Cavendish' Subgroup.

The objective of this study was to gain a deeper understanding of the morphoanatomical and histochemical structures that compose the nectary of pistillate flowers (female), which are involved in the female fertility of banana plants belonging to the 'Cavendish' subgroup. The diploid Calcutta 4 and the Grand Naine cultivar were used for the assessment. Five stages of floral development were proposed. Pistillate flower nectaries were subjected to morphological characterization, morphoanatomy, and histochemical tests (phenolic compounds, proteins, and lipids). Morphoanatomical analysis revealed a greater presence of narrow nectariferous ducts and more developed pluristratified papillae in Calcutta 4. In contrast, Grand Naine displayed cell disintegration in nectariferous ducts and pluristratified papillae, absent transmitting tissue, and greater amounts of vascular bundles at anthesis. However, Calcutta 4 displayed no changes in the nectariferous duct at any of the stages. An association was found between phenolic compounds and lipids in vacuoles adjacent to the vascular bundles, with greater amounts found in Grand Naine. The localization of phenolic compounds may suggest that these compounds play a role in nectar secretion or the oxidation of the nectary region, ultimately limiting the growth and passage of the pollen tube and preventing ovule fertilization.

Phenolic Compounds and Oxidative Enzymes Involved in Female Fertility in Banana Plants of the Cavendish Subgroup.

The present study investigated phenolic compounds and enzymes involved in female fertility in banana plants of the Cavendish subgroup. The wild diploid Calcutta 4 and commercial cultivar Grand Naine (Cavendish subgroup) were used. The following five stages of floral development were proposed: S1 (partial vertical emission), S2 (total vertical emission), S3 (total horizontal emission), S4 (pre-anthesis), and S5 (anthesis). Following collection, pistillate (female) flowers were freeze-dried for the subsequent removal of nectaries and the analysis of phenolic compounds (PCs), antioxidant activity (DPPH and ABTS), enzymatic activity [peroxidase (POD) and polyphenol oxidase (PPO)], and total proteins (TPs). The highest values were recorded at the S3 stage, with the values decreasing as the stages progressed (until S5). At the S3 stage, the following results were obtained for Calcutta 4 and Grand Naine, respectively: PCs (32.4 and 36.1 mg GAE·g-1); DPPH (735.2 and 454.4 µM TE·g-1); ABTS (647.8 and 555.5 µM TE·g-1); POD (0.8 and 0.7 µmol·min-1·g-1); PPO (3.7 and 2.7 µmol·min-1·g-1); and TP (3.2 and 2.4 µmol·min-1·g-1). These results indicate that PCs and enzymes regulate female fertility, suggesting that crossbreeding should be performed from the S3 stage in cultivars of the Cavendish subgroup to achieve fruits with seeds.

Pre-selection of banana somaclones resistant to Fusarium oxysporum f. sp. cubense, subtropical race 4.

- Fusarium wilt, caused by Fusarium oxysporum f. sp. cubense (Foc), is one of the most destructive diseases affecting banana crops worldwide. Therefore, the development of resistant cultivars is a promising alternative to mitigate the effects of the disease on banana plantations. The objectives of this study were to induce somaclonal variation in banana cultivars of the Silk and Cavendish types and to select somaclones resistant to subtropical race 4, thereby enabling the production of fruit in areas where this race is present. Shoot clump apexes of the Grand Naine and Maçã (Silk) cultivars were grown in MS medium. The cultures were subcultured four times. They were then challenged with fusaric acid (FA) in an experiment consisting of four treatments with different concentrations (0.1, 0.2, 0.3, and 0.4 mM) and five repetitions, each consisting of a Petri dish containing seven multiple shoot clumps in MS culture medium supplemented with 2.5 mg/L benzylamine purine. Multiple shoot clumps without the addition of FA were also used in the experiment, and were subcultured three times and maintained in a dark room. The multiple shoot clumps that survived the treatment with FA were transferred to MS medium and maintained in the growth chamber in the presence of light. The regenerated plants were later planted in tanks containing soil infested with an isolate classified as Foc subtropical race 4 (Foc STR4), and were evaluated for resistance to the pathogen at 90 days after inoculation (d.a.i.). Pathogen structures were confirmed by root clarification and root staining technique. All somaclones of the Maçã (Silk) cultivar were susceptible to Fusarium wilt and two somaclones of the Grand Naine cultivar were selected as resistant. The addition of FA as a selective agent was effective in the selection of somaclones among plants of the Grand Naine cultivar, as shown by the selection of two somaclones resistant to Foc STR4. The next step will consist of the agronomic and market potential validation of the selected somaclones, aiming to confirm their potential use by producers.

Improvements in the Resistance of the Banana Species to Fusarium Wilt: A Systematic Review of Methods and Perspectives.

The fungus Fusarium oxysporum f. sp. cubense (FOC), tropical race 4 (TR4), causes Fusarium wilt of banana, a pandemic that has threatened the cultivation and export trade of this fruit. This article presents the first systematic review of studies conducted in the last 10 years on the resistance of Musa spp. to Fusarium wilt. We evaluated articles deposited in different academic databases, using a standardized search string and predefined inclusion and exclusion criteria. We note that the information on the sequencing of the Musa sp. genome is certainly a source for obtaining resistant cultivars, mainly by evaluating the banana transcriptome data after infection with FOC. We also showed that there are sources of resistance to FOC race 1 (R1) and FOC TR4 in banana germplasms and that these data are the basis for obtaining resistant cultivars, although the published data are still scarce. In contrast, the transgenics approach has been adopted frequently. We propose harmonizing methods and protocols to facilitate the comparison of information obtained in different research centers and efforts based on global cooperation to cope with the disease. Thus, we offer here a contribution that may facilitate and direct research towards the production of banana resistant to FOC.

Bioactive amines changes during the ripening and thermal processes of bananas and plantains.

Bioactive amines are found in food and can be relevant for the assessment of fruits shelf life and nutritional quality. The pulp and peel of 20 banana and plantain were analyzed and the bioactive amine content varied according to the genotype, ripening stage, fruit tissue and thermal processing. In most of the analyzed genotypes, tyramine, histamine, dopamine, serotonin, spermidine, and spermine were decreased during the ripening process in the pulps. By contrast, there was an increase in putrescine level. In many genotypes of plantains, the serotonin and dopamine contents in pulp decreased until stage 5 and increased at stage 7. Peels contain higher levels of serotonin, dopamine, histamine and tyramine than pulps. Additionally, thermal processing affects the content of amines present in fruit. Boiling with the peel should be preferred in domestic preparations, regardless of the genotype used.

Water stress in Musa spp.: A systematic review.

BACKGROUND: The cultivation of bananas and other plants is limited by environmental stresses caused by climate change. In order to recognize physiological, biochemical and molecular components indicated to confer tolerance to water stress in Musa spp. we present the first systematic review on the topic. METHODS: A systematic literature review was conducted using four databases for academic research (Google Academic, Springer, CAPES Journal Portal and PubMed Central). In order to avoid publication bias, a previously established protocol and inclusion and exclusion criteria were used. RESULTS: The drought tolerance response is genotype-dependent, therefore the most studied varieties are constituted by the "B" genome. Tolerant plants are capable of super-expressing genes related to reisistance and defense response, maintaining the osmotic equilibrium and elimination of free radicals. Furthermore, they have higher amounts of water content, chlorophyll levels, stomatic conductance and dry root matter, when compared to susceptible plants. CONCLUSIONS: In recent years, few integrated studies on the effects of water stress on bananas have been carried out and none related to flood stress. Therefore, we highlight the need for new studies on the mechanisms of differentially expressed proteins in response to stress regulation, post-translational mechanisms and epigenetic inheritance in bananas.

Physicochemical characterization of banana fruit by univariate and multivariate procedures / Caracterização físico-química de frutos de bananeira por procedimentos uni e multivariados

Breeding genotypes need to be characterized and evaluated in different soil and climatic conditions. There are few studies on association between characters evaluated and their contribution to banana genetic diversity, being essential to guide genetic breeding programs. This study aimed to evaluate the physicochemical characters of banana genotypes, to estimate associations between characters, to determine the relative importance of characters to study on genetic dissimilarity, and to indicate new genotypes to coastal plain region of Sergipe. Fruits from thirteen genotypes were used: Prata (FHIA-18, BRS Platina, PV94-01, BRS Garantida, YB42-47, Pacovan, and Prata Anã), Maçã (BRS Princesa, BRS Tropical, and Maçã), Ibota (Caipira), Gros Michel (Bucaneiro), and Mysore (Thap Maeo). The experimental design was randomized blocks, with thirteen genotypes and three replications. There is physicochemical variability of fruits between genotypes of same genomic group and subgroup, and between hybrids originated from same progenitor. Content of total sugars has greater contribution to genetic diversity among the genotypes, followed by fruit mass and pulp mass, and starch content in two cycles. Associations between fruit length, fruit diameter, and fruit mass and pulp mass in two production cycles based on phenotypic correlation are highly significant. Hybrids FHIA-18, PA94-01, YB42-47, and BRS Tropical, BRS Princesa, and Bucaneiro cultivars are promising for recommendation on coastal plain regions.

Genótipos melhorados necessitam ser caracterizados e avaliados em diferentes condições edafoclimáticas. Existem poucos estudos sobre a associação entre os caracteres avaliados e sua contribuição para a diversidade genética da banana, sendo imprescindíveis para orientar programas de melhoramento genético. O objetivo desse trabalho foi avaliar os caracteres físico-químicos de frutos de genótipos de bananeira, estimar as associações entre caracteres, determinar a importância relativa dos caracteres para o estudo da dissimilaridade genética e indicar novos genótipos para a região de Tabuleiros Costeiros de Sergipe. Foram utilizados frutos de treze genótipos: tipo Prata (FHIA-18, BRS Platina, PV94-01, BRS Garantida, YB42-47, Pacovan e Prata-Anã), Maçã (BRS Princesa, BRS Tropical e Maçã), Ibota (Caipira), Gros Michel (Bucaneiro) e o Mysore (Thap Maeo). O delineamento experimental foi em blocos ao acaso, com treze genótipos e três repetições. Existe variabilidade físico-química dos frutos entre os genótipos do mesmo grupo genômico e subgrupo, e entre híbridos originados da mesma genitora. O teor de açúcares totais apresenta maior contribuição para a diversidade genética entre os genótipos, seguido da massa do fruto com e sem casca e teor de amido nos dois ciclos. As associações entre comprimento do fruto, o diâmetro, massa do fruto e da polpa nos dois ciclos de produção com base na correlação fenotípica são altamente significativas. Os híbridos FHIA-18, PA94-01, YB42-47 e as cultivares BRS Tropical, BRS Princesa e Bucaneiro são promissores para recomendação nos Tabuleiros Costeiros.

Gene expression analysis in Musa acuminata during compatible interactions with Meloidogyne incognita.

Background and Aims: Endoparasitic root-knot nematodes (RKNs) ( Meloidogyne spp.) cause considerable losses in banana ( Musa spp.), with Meloidogyne incognita a predominant species in Cavendish sub-group bananas. This study investigates the root transcriptome in Musa acuminata genotypes 4297-06 (AA) and Cavendish Grande Naine (CAV; AAA) during early compatible interactions with M. incognita . Methods: Roots were analysed by brightfield light microscopy over a 35 d period to examine nematode penetration and morphological cell transformation. RNA samples were extracted 3, 7 and 10 days after inoculation (DAI) with nematode J2 juveniles, and cDNA libraries were sequenced using lllumina HiSeq technology. Sequences were mapped to the M. acuminata ssp. malaccensis var. Pahang genome sequence, differentially expressed genes (DEGs) identified and transcript representation determined by gene set enrichment and pathway mapping. Key Results: Microscopic analysis revealed a life cycle of M. incognita completing in 24 d in CAV and 27 d in 4279-06. Comparable numbers of DEGs were up- and downregulated in each genotype, with potential involvement of many in early host defence responses involving reactive oxygen species and jasmonate/ethylene signalling. DEGs revealed concomitant auxin metabolism and cell wall modification processes likely to be involved in giant cell formation. Notable transcripts related to host defence included those coding for leucine-rich repeat receptor-like serine/threonine-protein kinases, peroxidases, thaumatin-like pathogenesis-related proteins, and DREB, ERF, MYB, NAC and WRKY transcription factors. Transcripts related to giant cell development included indole acetic acid-amido synthetase GH3.8 genes, involved in auxin metabolism, as well as genes encoding expansins and hydrolases, involved in cell wall modification. Conclusions: Expression analysis in M. acuminata during compatible interactions with RKNs provides insights into genes modulated during infection and giant cell formation. Increased understanding of both defence responses to limit parasitism during compatible interactions and effector-targeted host genes in this complex interaction will facilitate the development of genetic improvement measures for RKNs.

Ripening and shelf life of 'BRS Caipira' banana fruit stored under room temperature or refrigeration / Amadurecimento e vida útil de frutos de bananeira 'BRS Caipira' armazenados em temperatura ambiente ou refrigeração

BRS Caipira variety, internationally known as 'Yangambi km 5', is an alternative to meet the demand of 'Maçã'-type fruit due to its resistance to Panama disease. This study had the objective of generating information about 'BRS Caipira' fruit ripening and cold storage potential. For the ripening study fruits were stored under room temperature conditions (25±2°C / 58±6% U.R.) and assessed for postharvest life evaluation and characterization of seven maturity stages based on peel color: completely green - MS1; green with yellow traces - MS2; more green than yellow - MS3; more yellow than green - MS4; yellow with green tips - MS5; completely yellow - MS6; yellow with brown spots - MS7. For the cold storage potential study, fruits at MS1 were cold stored (14±1°C / 53±2% U.R.) for 28 days. Weekly, fruits were transferred to room temperature to ripen until MS6 when were assessed for quality attributes. Ripening of 'BRS Caipira' fruit was characterized as slow between MS1 and MS2 (averaging five days), then fast between MS2 and MS6 (up to four days in average), and undergoing determinant changes between MS6 and MS7: pulp yield reached 80%, titratable acidity reduced by 50% and ratio increased by 78%. Cold storage extended shelf life by up to 19 days as compared with control, without visible symptoms of chilling injury, although tends to reduce soluble solids in ripe fruit. Maximum recommended time for storage of 'BRS Caipira' fruit at 14°C is 21 days, since it allows a few more days under room temperature until fruit reach MS6.

A variedade BRS Caipira, internacionalmente conhecida como 'Yangambi km 5', é uma alternativa para atender a demanda de frutos do tipo Maçã, devido à sua resistência ao mal-do-Panamá. Este estudo objetivou gerar informações sobre o amadurecimento e o potencial de armazenamento refrigerado de frutos de 'BRS Caipira'. Para o estudo do amadurecimento, frutos foram armazenados sob temperatura ambiente (25±2°C / 58±6% U.R.) e avaliados para vida pós-colheita e caracterização de sete estádios de maturação baseados na cor da casca: completamente verde - MS1; verde com traços amarelos - MS2; mais verde que amarelo - MS3; mais amarelo que verde - MS4; amarelo com pontas verdes - MS5; completamente amarelo - MS6; amarelo com manchas marrons - MS7. Para o estudo de potencial de armazenamento refrigerado, frutos em MS1 foram armazenados em câmara fria (14±1°C / 53±2% U.R.) por 28 dias. Semanalmente, uma amostra de frutos era retirada para a temperatura ambiente e avaliados para atributos de qualidade. O amadurecimento de frutos de 'BRS Caipira' foi caracterizado como lento entre MS1 e MS2 (cinco dias em média), rápido entre MS2 e MS6 (até quatro dias em média), e que passa por alterações determinantes entre MS6 e MS7: rendimento em polpa atingiu 80%; acidez reduziu pela metade; e ratio aumentou 78%. A refrigeração prolongou a vida útil dos frutos em até 19 dias em relação ao controle, sem sintomas visíveis de danos por frio, embora tenda a reduzir o teor de sólidos solúveis nos frutos maduros. O período máximo recomendado para armazenagem de frutos de 'BRS Caipira' a 14°C é de 21 dias, tempo que permitiria mais alguns dias em temperatura ambiente para os frutos atingirem o estádio MS6.

Deficiências de macronutrientes no estado nutricional de mudas de bananeira tipo prata / Deficiencies of macronutrients on nutritional status of prata type bananas seedlings

Objetivou-se avaliar o efeito da deficiência dos macronutrientes no crescimento e estado nutricional de mudas de bananeira tipo Prata. Os tratamentos foram dois genótipos Prata-Anã e seu híbrido PA42-44 cultivados em solução nutritiva na presença e ausência dos macronutrientes. Após 100 dias foram avaliados a área foliar, a massa seca das raízes, rizoma e folhas e, os teores de macronutrientes na massa seca de cada parte da planta. Com esses resultados calcularam-se os índices: eficiência de absorção, de transporte e de utilização dos macronutrientes. As deficiências de N para Prata-Anã e Mg para híbrido PA42-44 foram as que mais limitaram o crescimento dos genótipos. O acúmulo de nutrientes correspondeu à seguinte ordem N > K > Ca > P > Mg > S para Prata-Anã e N > K > Ca > P > S > Mg para o híbrido PA42-44, o que reflete as exigências da planta. O híbrido PA42-44 apresentou maior eficiência de absorção de todos macronutrientes, em solução completa. Os tratamentos não diferiram quanto a eficiência de transporte dos macronutrientes, exceto na omissão de Mg, onde a maior eficiência ocorreu no híbrido PA 42-44. A omissão de P, K, Ca, Mg e S na nutrição dos dois genótipos de banana resulta em maior eficiência de utilização, comparado com as plantas nutridas adequadamente.

This work objective to evaluate the effect of macronutrient deficiencies no growth and nutritional status of banana seedlings type Prata. The treatments were two genotypes Prata-Anã and its hybrid PA42-44 grown in nutrient solution in the presence and absence of macronutrients. Leaf area, dry matter of roots, rhizome and leaves, and the macronutrient dry mass of each plant were evaluated after 100 days. With these results was calculated the indices: absorption, transport and utilization efficiency of macronutrientes. The deficiencies of N for Prata-Anã and Mg for PA42- 44 hybrid were most limited the growth of genotypes. The nutrient accumulation corresponded to the following order N > K > Ca > P > Mg > S for the Prata-Anã and N > K > Ca > P > S > Mg for the PA42-44 hybrid, which reflect the plant requirements. The PA 42-44 hybrid showed higher absorption efficiency of all macronutrients, in complete solution. The treatments no differ regarding to the macronutrients transport efficiency, except the omission of Mg, where higher efficiency occurred in hybrid PA 42-44. The P, K, Ca, Mg and S omission in the nutrition of two banana genotypes results in increased utilization efficiency, compared with plants growing adequately.

Characterisation of metabolic profile of banana genotypes, aiming at biofortified Musa spp. cultivars.

The banana is an important, widely consumed fruit, especially in areas of rampant undernutrition. Twenty-nine samples were analysed, including 9 diploids, 13 triploids and 7 tetraploids, in the Active Germplasm Bank, at Embrapa Cassava & Fruits, to evaluate the bioactive compounds. The results of this study reveal the presence of a diversity of bioactive compounds, e.g., catechins; they are phenolic compounds with high antioxidant potential and antitumour activity. In addition, accessions with appreciable amounts of pVACs were identified, especially compared with the main cultivars that are currently marketed. The ATR-FTIR, combined with principal components analysis, identified accessions with distinct metabolic profiles in the fingerprint regions of compounds important for human health. Likewise, starch fraction characterisation allowed discrimination of accessions according to their physical, chemical, and functional properties. The results of this study demonstrate that the banana has functional characteristics endowing it with the potential to promote human health.

Genetic diversity and population structure of Musa accessions in ex situ conservation.

BACKGROUND: Banana cultivars are mostly derived from hybridization between wild diploid subspecies of Musa acuminata (A genome) and M. balbisiana (B genome), and they exhibit various levels of ploidy and genomic constitution. The Embrapa ex situ Musa collection contains over 220 accessions, of which only a few have been genetically characterized. Knowledge regarding the genetic relationships and diversity between modern cultivars and wild relatives would assist in conservation and breeding strategies. Our objectives were to determine the genomic constitution based on Internal Transcribed Spacer (ITS) regions polymorphism and the ploidy of all accessions by flow cytometry and to investigate the population structure of the collection using Simple Sequence Repeat (SSR) loci as co-dominant markers based on Structure software, not previously performed in Musa. RESULTS: From the 221 accessions analyzed by flow cytometry, the correct ploidy was confirmed or established for 212 (95.9%), whereas digestion of the ITS region confirmed the genomic constitution of 209 (94.6%). Neighbor-joining clustering analysis derived from SSR binary data allowed the detection of two major groups, essentially distinguished by the presence or absence of the B genome, while subgroups were formed according to the genomic composition and commercial classification. The co-dominant nature of SSR was explored to analyze the structure of the population based on a Bayesian approach, detecting 21 subpopulations. Most of the subpopulations were in agreement with the clustering analysis. CONCLUSIONS: The data generated by flow cytometry, ITS and SSR supported the hypothesis about the occurrence of homeologue recombination between A and B genomes, leading to discrepancies in the number of sets or portions from each parental genome. These phenomenons have been largely disregarded in the evolution of banana, as the "single-step domestication" hypothesis had long predominated. These findings will have an impact in future breeding approaches. Structure analysis enabled the efficient detection of ancestry of recently developed tetraploid hybrids by breeding programs, and for some triploids. However, for the main commercial subgroups, Structure appeared to be less efficient to detect the ancestry in diploid groups, possibly due to sampling restrictions. The possibility of inferring the membership among accessions to correct the effects of genetic structure opens possibilities for its use in marker-assisted selection by association mapping.

Viabilidade in vitro de grãos de pólen de bananeira sob diferentes concentrações de ácido bórico e sacarose / In vitro viability of banana pollen grain under different concentrations of boric acid and sucrose

Neste trabalho, objetivou-se avaliar a germinação do grão de pólen e o comprimento do tubo polínico das bananeiras diplóides M53, 8987-01 e 9197-03, Calcutá, Lidi e 86B79-12. O delineamento utilizado foi inteiramente casualizado com cinco doses de sacarose (0, 5, 10, 15, 20 por cento) e seis concentrações de ácido bórico (0, 100, 200, 300, 400 e 500 Mg L-1) com quatro repetições. Foram utilizados grãos de pólen retirados da inflorescência masculina dos diplóides Musa acuminata (AA). O pólen foi distribuído em placas de Petri, contendo o seguinte meio de cultura: 1,27 mM de Ca(NO3)2.2H2O, 0,87 mM de MgSO4.7H2O, 0,99 mM de KNO3, 0,7 por cento de ágar com pH ajustado para 7,0, variando as concentrações de sacarose e de ácido bórico. As avaliações foram realizadas 24 horas após a distribuição do pólen no meio de cultura. O meio de cultura padrão para germinação de grãos de pólen suplementado com 15 por cento de sacarose proporcionou uma maior percentagem de germinação para os diplóides de bananeira avaliados. A concentração de ácido bórico adicionado ao meio de cultura para a germinação de grãos de pólen de bananeira diplóide é dependente do genótipo.

The objective of this work was to evaluate the germination of pollen grain and pollen tube length of banana diploids (M53, 8987-01 e 9197-03, Calcutta, Lidi and 86B79-12). Five concentrations of sucrose (0, 5, 10, 15 and 20 percent) and six concentrations of boric acid (0, 100, 200, 300, 400 and 500 mg L-1) were used, in a completely randomized experimental design, with four replicates. The pollen was distributed in Petri dishes containing the following culture medium: 1.27 mM Ca(NO3)2.2H2O, 0.87 mM MgSO4.7H2O, 0.99 mM KNO3, and 0.7 percent agar; pH adjusted to 7.0, varying the sucrose and boric acid concentrations. The evaluations were performed 24 hours after the distribution of the pollen in the culture medium. The standard culture medium for germination of pollen grains with 15 percent sucrose provided the highest germination percentage for the banana diploids. The concentration of boric acid added to the culture medium for pollen grain germination of diploid banana is dependent on the genotype.

Caracterização de acessos de bananeira com base na concentração de compostos funcionais / Characterization of banana accessions with base on functional compounds

O objetivo deste trabalho foi determinar a concentração de polifenóis totais, flavonóides, vitamina C e carotenóides totais em 61 acessos de banana pertencentes ao Banco Ativo de Germoplasma de bananeira da Embrapa Mandioca e Fruticultura. Foram detectadas diferenças significativas para todas as características analisadas por meio da análise de variância. A média para os teores de polifenóis totais entre os 61 acessos de banana foi de 38,06mg 100g-1, com variação de 12,51mg 100g-1 para o triplóide 'Torp' a 257,80mg 100g-1 para o tetraplóide 'Teparod'. A média para flavonóides foi de 2,09mg 100g-1, variando de 0,85mg 100g-1 ('Maravilha' AAAB) a 6,63mg 100g-1 ('Teparod' ABBB). Para vitamina C, a média foi de 21,60mg 100g-1, variando de 8,60mg 100g-1 (tetraplóide 'Bucaneiro') a 76,82mg 100g-1 (tetraplóide 'Teparod'). A média do teor de carotenóides totais foi de 4,34mg g-1, variando de 1,18mg g-1 ('Champa Madras', triplóide ABB) a 19,24mg g-1 ('Saney', triplóide AAB). Os diplóides Modok Gier e NBA-14 apresentaram, respectivamente, quatro e cinco vezes mais carotenóides totais que as cultivares do grupo Cavendish ('Nanica', 'Willians' e 'Lacatan'). Esses resultados permitem concluir sobre a possibilidade da obtenção de cultivares com altos níveis de compostos funcionais por meio de cruzamentos e seleção. Cultivares com este perfil têm potencial como alimento funcional, ajudando a prevenir doenças, por meio da neutralização de radicais livres.

The objective of this research was to determine the concentration of polyphenols, flavonols, vitamin C and carotenoid and in 61 banana accessions from Musa germplasm collection from Embrapa Cassava and Fruits, Brazil. Was detected significant differences for all characteristic analyzed in ANOVA. The average for polyphenols among the 61 accessions was of 38.06mg 100g-1, with variation of 12.51mg 100g-1 for the triploid 'Torp' to 257.80mg 100g-1 for the tetraploid 'Teparod'. The average for flavonols was of 2.09mg 100g-1, ranging of 0.85mg 100g-1 ('Maravilha' AAAB) to 6.63mg 100g-1 ('Teparod' ABBB). The average for vitamin C was of 21.60mg 100g-1, ranging of 8.60mg 100g-1 (tetraploid 'Bucaneiro') to 76.82mg 100g-1 (tetraploid 'Teparod'). The average of the total carotenoids was of 4.34g g-1, ranging of 1.18g g-1 ('Champa Madras', triploid ABB) to 19.24g g-1 ('Saney', triploid AAB). Diploids Modok Gier and NBA-14 exhibited 4- and 5-fold increased carotenoid content in comparison to the representatives from the Cavendish group ('Nanica', 'Willians' and 'Lacatan'). These results allow ending about the possibility of the obtaining new cultivars with high levels of functional compositions through crossings and selection. Cultivar with this profile has potential of neutralizing free radicals and to prevent diseases.