Review: biological, antioxidant and phytochemical activities of Musa spp / Revisão: atividades biológicas, antioxidante e fitoquímica de Musa spp

Banana (Musa spp.) is a food with high nutritional value. Studies about its compounds have increased considerably due to the antioxidant and biological activities of the fruit. Thus, this article synthesized and organized data related to the phytochemical constituents, as well as antioxidant and biological activities of Musa acuminata, Musa balbisiana and Musa paradisiaca, and evaluated the mutual influence and correlation of these activities. A bibliographic review was performed using the scientific databases Google Scholar, SciELO, Periódicos CAPES, Scientific Electronic Library Online (SciELO), Science Direct, PubMed and Scopus, applying the following terms: Musa spp., antioxidant, biological and phytochemical activities, combined by the Boolean operator AND. A total of 28 articles were selected from 2017 to 2022. The results indicated that bananas are rich in flavonoids, showed good performance in DPPH and FRAP antioxidant assays and have antibacterial, anticancer and antifungal potential. Previous literature reported that phytochemical constituents improved antioxidant performance, thereby enhancing the biological activities described.

Banana (Musa spp.) é caracterizada como um alimento que possui alto valor nutricional e, atualmente, pesquisas sobre seus compostos têm crescido de forma considerável, tendo em vista a presença de atividades antioxidantes e biológicas que o fruto possui. Dessa forma, o objetivo desse artigo é sintetizar e organizar informações sobre os constituintes fitoquímicos, as atividades antioxidantes e as atividades biológicas encontradas em Musa acuminata, Musa balbisiana e Musa paradisíaca e avaliar se tais atividades se relacionam e se há influência de uma sobre a outra. Para tanto, foi feita uma revisão bibliográfica nas plataformas: Google Acadêmico, SciELO, Periódicos Capes, Scientific Eletronic Libary Online (SciELO), Science Direct, PubMed e scopus, por meio dos termos Musa spp, antioxidant, activities biologics e phytochemical intercalados pelo operador booleano AND. O recorte temporal foi de 2017 a 2022 e 28 trabalhos foram selecionados para análise. Em relação à constituição fitoquímica foi possível concluir que as variedades avaliadas são ricas em flavonoides. Para a atividade antioxidante observou-se que Musa spp. apresentam boa performance nos testes antioxidantes do DPPH e FRAP. E para as atividades biológicas as espécies analisadas se destacaram pelo seu potencial como antibacteriano, anticancerígeno e antifúngico. Vários trabalhos revisados apresentaram que os constituintes químicos presentes nas espécies favorecem o bom desempenho antioxidante, esse, por sua vez, influencia positivamente no desempenho das atividades biológicas descritas.

Potential nutrient-response curves and sufficiency ranges for ‘Prata-An㒠banana cultivated under two environmental conditions

Proper plant nutrition is critical to increasing the yield of bananas. The objective was to establish the potential nutrient-response curves and sufficiency ranges using the boundary line approach (BLA) and the method proposed by Kenworthy (MK) to assess the nutritional status of ‘Prata-An㒠bananas cultivated under two environmental conditions. The study was carried out using a database comprising leaf nutrient concentrations and banana yields grown at Missão Velha, Ceará, and Ponto Novo, Bahia, Brazil. The reference population consisted of high-yielding plants with yields greater than the mean yield plus 0.5 standard deviation. The database was divided into two datasets. One contained 253 leaf analysis results and a reference population with a mean yield greater than 39.81 t ha−1 yr−1 at Missão Velha. The other contained 147 samples and a reference population with a mean yield greater than 41.69 t ha−1 yr−1 at Ponto Novo. The sufficiency ranges obtained by the BLA for ‘Prata-An㒠banana in Bahia and Ceará, respectively, are: a) for macronutrients (g kg−1): N (19.3-22.0) and (19.9-22.1); P (1.4-2.0) and (1.4-1.6); K (22.6-32.2) and (24.0-31.3); Ca (4.6-6.5) and (5.3-5.8); Mg (1.8-2.6) and (2.1-2.7); S (1.3-2.0) and (1.3-1.5); b) for micronutrients (mg kg−1): B (8.4-13.0) and (13.7-16.4); Cu (5.6-8.4) and (4.4-5.2); Fe (54.2-77.6) and (39.0-55.0); Mn (140.1-222.8) and (64.0-91.0); Zn (13.5-18.3) and (12.4-14.5). The sufficiency ranges obtained by the BLA are more assertive when assessing the nutritional status for ‘Prata-An㒠banana.

Potential nutrient-response curves and sufficiency ranges for ‘Prata-Anã banana cultivated under two environmental conditions

Proper plant nutrition is critical to increasing the yield of bananas. The objective was to establish the potential nutrient-response curves and sufficiency ranges using the boundary line approach (BLA) and the method proposed by Kenworthy (MK) to assess the nutritional status of ‘Prata-Anã bananas cultivated under two environmental conditions. The study was carried out using a database comprising leaf nutrient concentrations and banana yields grown at Missão Velha, Ceará, and Ponto Novo, Bahia, Brazil. The reference population consisted of high-yielding plants with yields greater than the mean yield plus 0.5 standard deviation. The database was divided into two datasets. One contained 253 leaf analysis results and a reference population with a mean yield greater than 39.81 t ha−1 yr−1 at Missão Velha. The other contained 147 samples and a reference population with a mean yield greater than 41.69 t ha−1 yr−1 at Ponto Novo. The sufficiency ranges obtained by the BLA for ‘Prata-Anã banana in Bahia and Ceará, respectively, are: a) for macronutrients (g kg−1): N (19.3-22.0) and (19.9-22.1); P (1.4-2.0) and (1.4-1.6); K (22.6-32.2) and (24.0-31.3); Ca (4.6-6.5) and (5.3-5.8); Mg (1.8-2.6) and (2.1-2.7); S (1.3-2.0) and (1.3-1.5); b) for micronutrients (mg kg−1): B (8.4-13.0) and (13.7-16.4); Cu (5.6-8.4) and (4.4-5.2); Fe (54.2-77.6) and (39.0-55.0); Mn (140.1-222.8) and (64.0-91.0); Zn (13.5-18.3) and (12.4-14.5). The sufficiency ranges obtained by the BLA are more assertive when assessing the nutritional status for ‘Prata-Anã banana.(AU)

Nutritional value of pre-dried banana tree pseudostem ammoniated with protected urea / Valor nutricional de pseudocaule de bananeira pré-secado amonizados com ureia protegida

The objective of this study was to evaluate the chemical composition, pH and rumen degradability of banana tree pseudostems pre-dried and ammoniated with different doses of urea (0, 0.5, 1.0, 1.5 and 2.0% in natural matter). The experiment consisted of five treatments (doses of urea) with six replications, following a completely randomized design. There was a linear increase in the pH (P < 0.01) of the banana tree pseudostems pre dried with the inclusion of urea. There was no difference (P > 0.05) in dry matter, ash, neutral detergent fiber, acid detergent fiber, lignin, non-fibrous carbohydrates and total digestible nutrients; the averages were 31.58, 18.82, 46.43, 9.30, 11.87 and 42.52%, respectively. The inclusion of 2% urea increased the crude protein content (P < 0.01) by 42.75%, the soluble fraction "a" by 31.82%, and the potential and effective degradability of dry matter by 15.49% compared to that of the control group (without urea). The potentially degradable fraction, time of colonization and ruminal repletion of the neutral detergent fiber of the pre-dried banana tree pseudostems were not altered with the inclusion of urea (P > 0.05). The ammonization of the pre-dried banana tree pseudostems with 2% of urea improved the chemical composition and rumen degradability of the dry matter(AU)

O objetivo deste estudo foi avaliar a composição química, pH e degradabilidade ruminal de pseudocaule de bananeira pré-secado e amonizados com diferentes doses de ureia (0, 0,5, 1,0, 1,5 e 2,0% em matéria natural). O experimento consistiu de cinco tratamentos (doses de ureia) com seis repetições, seguindo um delineamento inteiramente casualizado. Houve aumento linear do pH (P < 0,01) do pseudocaule de bananeira pré-secado com a inclusão de ureia. Não houve diferença (P > 0,05) na matéria seca, cinzas, fibra em detergente neutro, fibra em detergente ácido, lignina, carboidratos não fibrosos e nutrientes digestíveis totais; as médias foram 31,58; 18,82; 46,43; 9,30; 11,87 e 42,52%, respectivamente. A inclusão de 2% de ureia aumentou o teor de proteína bruta (P < 0,01) em 42,75%, a fração solúvel "a" em 31,82% e a degradabilidade potencial e efetiva da matéria seca em 15,49% em relação ao grupo controle (sem ureia). A fração potencialmente degradável, o tempo de colonização e a repleção ruminal da fibra em detergente neutro dos pseudocaules de bananeira pré-secado não foram alterados com a inclusão da ureia (P > 0,05). A amonização do pseudocaule de bananeira pré-secado com 2% de ureia melhorou a composição química e a degradabilidade ruminal da matéria seca.(AU)

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.

El plátano: indicador de hambre y escasez de alimentos en familias beneficiarias de programas alimentarios en Vigía del Fuerte, Colombia / Plantain: indicator of hunger and food shortage in families benefiting from food programs in Vigia del Fuerte, Colombia

RESUMEN Objetivo Interpretar la percepción de hambre y escasez de alimentos en familias beneficiarias de Programas alimentarios MANA (Mejoramiento Alimentario y Nutricional de Antioquia) en Vigía del Fuerte. Método La investigación se orientó desde el enfoque cualitativo, usando la Etnografía Focalizada como método, para la recolección de la información se utilizaron entrevistas individuales y grupos de discusión. Resultados Las comunidades de la cuenca del río Murrí están protegidas del hambre física por la disponibilidad permanente del plátano; el hambre está asociada a la ausencia de carne o "liga" y al hecho de comer "plátano vacío"; así mismo se refieren al hambre como la sensación de desasosiego, debido al dolor de cabeza y de estómago que experimentan de manera permanente e intensa. Conclusiones A pesar de que las comunidades vigieñas disponen durante todo el tiempo de plátano, protegiéndolas del hambre física; estas no lo aprecian así, como alimento que calma su hambre y los libera, de cierta manera, de la escasez, porque su presencia como único alimento disponible, les recuerda, precisamente, que tienen carencia y hambre.(AU)

ABSTRACT Objective To analyze the perception of hunger and food shortage in families benefiting from MANA (Food and Nutritional Improvement) food programs in Vigía del Fuerte, Colombia. Methods Qualitative research, using focused ethnography as a method for collecting information. Individual interviews and discussion groups were used. Results Even though the communities that live by the Murrí River basin are protected from physical hunger due to the constant availability of plantain or musa, hunger is associated with the absence of meat or liga and the fact that they feel forced to eat empty musa. They also refer to hunger as the feeling of uneasiness caused by headache and stomachache. Conclusions Despite the fact that the communities of Vigía del Fuerte have access to plantain throughout the year, thus protecting them from physical hunger, they do not consider it as food that could calm their hunger and free them from scarcity. This happens because its presence as the only food available reminds them, precisely, that they lack certain conditions and feel hunger.(AU)

Thap Maeo bananas: Fast ripening and full ethylene perception at low doses.

Brazil is a major producer and consumer of various banana types. Thap Maeo is a promising cultivar for the market due to its resistance to Black and Yellow Sigatoka disease. However, a lack of information and postharvest technologies concerning Thap Maeo physiology seems to be a significant problem limiting its expansion in the market. Thus, this study aims to establish Thap Maeo fruit's physical, biochemical, and physiological aspects, defining the best ethylene dosage for treatment considering fruit ripening parameters. Bananas were harvested and monitored during both natural and ethylene-induced ripening processes. Assessments of pulp firmness, peel color and endogenous ethylene production showed different profiles between ethylene-treated and non-treated fruits, whereas the ethylene responses concerning the carbohydrates and hormones profiles, as well as the ethylene receptors expression, were observed in all ethylene-treated fruits, even applying low concentrations of the hormone. It thus indicated the high ethylene-sensitivity of Thap Maeo cultivar. Such postharvest behaviors reverberate in lower ethylene requirements for treatment, which was established at 10µLL-1. Ethylene-inducible changes in fruit volatile compounds throughout ripening are also discussed.

Banana MaMADS Transcription Factors Are Necessary for Fruit Ripening and Molecular Tools to Promote Shelf-Life and Food Security.

Genetic solutions to postharvest crop loss can reduce cost and energy inputs while increasing food security, especially for banana (Musa acuminata), which is a significant component of worldwide food commerce. We have functionally characterized two banana E class (SEPALLATA3 [SEP3]) MADS box genes, MaMADS1 and MaMADS2, homologous to the tomato (Solanum lycopersicum) RIN-MADS ripening gene. Transgenic banana plants repressing either gene (via antisense or RNA interference [RNAi]) were created and exhibited specific ripening delay and extended shelf-life phenotypes, including delayed color development and softening. The delay in fruit ripening is associated with a delay in climacteric respiration and reduced synthesis of the ripening hormone ethylene; in the most severe repressed lines, no ethylene was produced and ripening was most delayed. Unlike tomato rin mutants, banana fruits of all transgenic repression lines responded to exogenous ethylene by ripening normally, likely due to incomplete transgene repression and/or compensation by other MADS box genes. Our results show that, although MADS box ripening gene necessity is conserved across diverse taxa (monocots to dicots), unlike tomato, banana ripening requires at least two necessary members of the SEPALLATA MADS box gene group, and either can serve as a target for ripening control. The utility of such genes as tools for ripening control is especially relevant in important parthenocarpic crops such as the vegetatively propagated and widely consumed Cavendish banana, where breeding options for trait improvement are severely limited.

A influência da biodiversidade no entorno do cultivo sobre a expressão de protéinas de bananas produzidas no Vale do Ribeira / Influence of biodiversity surrounding the banana crop on protein expression of banana fruits produced on Vale do Ribeira, Brazil

As interações entre as plantas cultivadas e os outros organismos do agroecossistema podem afetar as características dos alimentos, trazendo implicações que abrangem desde as condições socioeconômicas dos produtores até a qualidade nutricional e sensorial dos produtos agrícolas. No caso de agroecossistemas equilibrados, a conservação da biodiversidade na propriedade contribui para diminuir a dependência de insumos externos, principalmente para o controle de pragas e doenças. Nesse sentido a produção de bananas no Vale do Ribeira constitui um mosaico de agroecossistemas, que pressionam os maiores e mais conservados remanescentes florestais de Mata Atlântica. A banana é um fruto climatérico típico, que mostrou grande potencial para o presente estudo, primeiro por ter boa parte de seus processos bioquímicos parcialmente elucidados, segundo, por apresentar seu genoma sequenciado e, terceiro, por ser um cultivo que permeia as áreas de Mata Atlântica do Vale do Ribeira. A perspectiva de análise do Proteoma label-free do fruto foi escolhida por sua ampla capacidade de compreensão de respostas biológicas, especialmente em delineamentos experimentais inéditos como esse, onde não é possível fazer grandes especulações acerca da resposta esperada. Dessa forma, inserido a um projeto de objetivo mais amplo, o objetivo deste trabalho foi avaliar a influência da biodiversidade atlântica no entorno do agroecossistema sobre a expressão de proteínas das bananas, considerando os aspectos físico-químicos, fisiológicos e bioquímicos, de modo a estimar as vias metabólicas influenciadas por esta condição ambiental. O projeto foi desenvolvido a partir da comparação de duas áreas comerciais de bananicultura que possuem idade e tratos culturais idênticos, sendo que a única diferença é que uma delas encontra-se cercada exclusivamente pelo monocultivo de bananeiras (parcela Controle) e a outra possui 60% do perímetro adjacente a um fragmento de Mata Atlântica (parcela Biodiversidade). Foi utilizada uma estratégia holística, contemplando diversos fatores do ambiente (fertilidade do solo e aspectos climáticos), da fisiologia da bananeira (diagnose foliar e infestação por doenças) e da banana (aspectos de qualidade, comportamento pós-colheita e proteoma da polpa). Os resultados mostram que as plantas da parcela biodiversidade apresentaram menor Índice de Severidade de Sigatoka Negra e produziram frutos com maior vida verde. Em relação ao Proteoma, as vias do Ciclo do ácido cítrico, do Metabolismo do piruvato e da Alanina, aspartato e glutamato foram as mais alteradas entre os frutos das duas parcelas, sinalizando uma maior tendência na síntese de ácidos graxos nos frutos da parcela Biodiversidade, que parece ter sido desviada para a síntese de aminoácidos nos frutos da parcela Controle. Algumas evidências reunidas sugerem que a presença da biodiversidade da Mata Atlântica no entorno do agroecossistema favorece o restabelecimento da homeostase vegetal, trazendo efeitos benéficos para o cultivo e para o fruto

Food quality is affected by crop and other agroecosystem organism interaction. These are a broad and diverse field of study, with unclear central issues, implying since socioeconomic condition of the producer, up to food quality, in terms of nutritional and sensorial issues. In this sense, banana production on Vale do Ribeira represents an agroecosystem mosaic, among the hugest and most conserved remaining Atlantic forest. Banana is a climacteric fruit with great potential for this study, firstly because its biochemical processes has been partially clarified, secondly, because its genome is already sequenced and, finally, because its cultivation area is surrounded by Atlantic forest areas from Vale do Ribeira. Proteomic label-free has been chosen, because of its great capability to understand biological response, especially in unprecedented experimental approaches, in which expectations cannot be done. Thereby, inserted on a broader project, the aim of this work was to evaluate the influence of Atlantic forest biodiversity surrounding the agroecosystem on protein expression of banana fruit, considering physic-chemical, physiological and biochemical aspects, in order to highlight metabolic pathways influenced by this environmental condition. The development of this project is based on the comparison of two banana commercial plots, with similar age and cultural practices, being the only difference between plots the presence of an Atlantic forest remanant on 60% of the Biodiversity plot, while the Control plot is exclusively surrounded by banana crop. It has been adopted an holistic approach, including several environmental factors (soil fertility and climatic factors), crop physiology factors (foliar diagnosis and disease severity) and banana fruit (quality attributes, post-harvest behavior and pulp proteome). Results revealed a reduction on disease severity and a longer fruit greenlife, which represents the time available to transport and marketing, for plants of the Biodiversity plot. The Proteome has shown alterations on metabolic pathways, as Citric acid cycle, Piruvate metabolism and Alanine, aspartate and glutamate metabolism, suggesting a greater tendency on fatty acid biosynthesis on fruits from Biodiversity plots, whereas fruits from Control plot seems to enhance amino acid biosynthesis. Some evidence suggest that the Atlantic forest surrounding the agroecosystem can be helpful to plant homeostasis, with benefits to the crop and fruit

O efeito da biodiversidade nativa da Mata Atlântica sobre o metabolismo de amadurecimento da banana (Musa acuminata AAA, Cavendish, cv. Nanicão) / he effect of the Atlantic Coastal Forest´s native biodiversity on the metabolism of banana ripening (Musa acuminata AAA, Cavendish, cv. Nanicão).

A produção de banana no Vale do Ribeira, em São Paulo, está inserida numa região que abriga um fragmento remanescente da Mata Atlântica, considerada um dos principais repositórios de biodiversidade e a floresta mais devastada entre os biomas brasileiros. Medidas sustentáveis, como a adoção de práticas agrícolas alternativas, tem sido o caminho para a conservação da fauna e flora, como também para a redução do uso inapropriado de terras que consequentemente pode aumentar o índice de doenças que atacam as plantas. Apesar, do razoável conhecimento científico sobre a fisiologia pós-colheita da banana, ainda não foram elucidadas quais são as respostas fisiológicas do fruto diante das alterações do meio ambiente decorrentes das práticas agroecológicas. Principalmente quais são os mecanismos de ação de compostos específicos, relacionados com a resistência da planta contra os estresses bióticos e abióticos. Também, não há uma abordagem analítica integrada que identifique os reguladores das vias metabólicas e possibilite um estudo holístico a nível molecular. Neste trabalho, foi avaliado o efeito da proximidade da biodiversidade nativa da Mata Atlântica sobre o perfil de metabólitos da banana (Musa acuminata AAA, Cavendish, cv. Nanicão). Foram comparados os frutos da parcela Biodiversidade, o qual apresenta 60% de seu perímetro limítrofe à floresta com a parcela Controle, inserida em uma área de produção de banana convencional. Neste estudo, foram determinados os perfis de etileno, vida verde, amido, açúcares, textura, cor, metabólitos semi-voláteis e não-voláteis e poliaminas. Como resultado, ambas as parcelas avaliadas apresentaram diferenças significativas no metabolismo primário e secundário, nos frutos verdes e maduros, respectivamente. Os metabólitos com diferença significativa entre as parcelas experimentais apresentaram maior envolvimento no metabolismo primário, sobretudo na via de biossíntese de aminoácidos, compostos precursores de uma ampla faixa de metabólitos secundários. As alterações quanto à abundância destes compostos são uma referência de que as mudanças do meio modificam as respostas da planta a estresses e estímulos

Banana production in the Ribeira Valley, in São Paulo, is set in a region that embraces a remaining fragment of the Atlantic Coastal Forest (Mata Atlântica), considered one of the main biodiversity repositories and the most devastated forest among the Brazilians´ biomes. Sustainable measures such as the adoption of alternative farming practices has been the way for the conservation of fauna and flora, but also to reduce the inappropriate use of land which in turn may increase the disease index that attack plants. Although, reasonable scientific knowledge about banana postharvest physiology is available, the fruit´s physiologic response given the environment changes as a result agroecological practices has not been elucidated yet. Primarily what are the mechanisms of action of specific compounds, related to plant resistance against biotic and abiotic stresses. In addition, there is not an integrated analytical approach to identify regulators of metabolic pathways and enable a holistic study at the molecular level. In this study, we evaluated the effect of proximity to the native biodiversity of the Atlantic Forest on the banana metabolites profile (Musa acuminata AAA, Cavendish, cv. Nanicão). The fruits of Biodiversity group were compared, which has 60% of its perimeter adjacent to the forest with the Control group set in a conventional banana production area. In this study, we determined the ethylene profiles, green life, starch, sugars, texture, colour, semi- volatile and non- volatile metabolites and polyamines. As a result, both evaluated groups showed significant differences in primary and secondary metabolism, green and ripen fruits respectively. The metabolites with significant differences between treatments showed greater involvement in primary metabolism, especially in amino acid biosynthesis, precursors of secondary metabolites. Changes in the abundance of these compounds are indicators that alterations in the environment modify the plant responses to stresses and stimuli

Control of Panama disease of banana by rotating and intercropping with Chinese chive (Allium tuberosum Rottler): role of plant volatiles.

Intercropping and rotating banana (Musa spp.) with Chinese chive (Allium tuberosum Rottler) has been used as an effective method to control Panama disease (Fusarium wilt) of banana in South China. However, the underlying mechanism is unknown. In this study, we used aqueous leachates and volatiles from Chinese chive to evaluate their antimicrobial activity on Fusarium oxysporum f. sp. cubense race 4 (FOC), the causal agent of Panama disease in banana, and identified the antifungal compounds. Both leaf and root leachates of Chinese chive displayed strong inhibition against FOC, but the concentrated leachates showed lower inhibition than the original leachates. In a sealed system volatiles emitted from the leaves and roots of Chinese chive inhibited mycelial growth of FOC. Volatile compounds emitted from the intact growing roots mimicking natural environment inhibited spore germination of FOC. We identified five volatiles including 2-methyl-2-pentenal and four organosulfur compounds (dimethyl trisulfide, dimethyl disulfide, dipropyl disulfide, and dipropyl trisulfide) from the leaves and roots of Chinese chive. All these compounds exhibited inhibitory effects on FOC, but 2-methyl-2-pentenal and dimethyl trisulfide showed stronger inhibition than the other three compounds. 2-Methyl-2-pentenal at 50-100 µl/l completely inhibited the mycelial growth of FOC. Our results demonstrate that antifungal volatiles released from Chinese chive help control Panama disease in banana. We conclude that intercropping and rotating banana with Chinese chive can control Panama disease and increase cropland biodiversity.

Genetic dissimilarity of putative gamma-ray-induced 'Preciosa-AAAB-Pome type' banana (Musa sp) mutants based on multivariate statistical analysis.

Bananas are among the most important fruit crops worldwide, being cultivated in more than 120 countries, mainly by small-scale producers. However, short-stature high-yielding bananas presenting good agronomic characteristics are hard to find. Consequently, wind continues to damage a great number of plantations each year, leading to lodging of plants and bunch loss. Development of new cultivars through conventional genetic breeding methods is hindered by female sterility and the low number of seeds. Mutation induction seems to have great potential for the development of new cultivars. We evaluated genetic dissimilarity among putative 'Preciosa' banana mutants generated by gamma-ray irradiation, using morphoagronomic characteristics and ISSR markers. The genetic distances between the putative 'Preciosa' mutants varied from 0.21 to 0.66, with a cophenetic correlation coefficient of 0.8064. We found good variability after irradiation of 'Preciosa' bananas; this procedure could be useful for banana breeding programs aimed at developing short-stature varieties with good agronomic characteristics.

Nuclear magnetic resonance water relaxation time changes in bananas during ripening: a new mechanism.

BACKGROUND: Nuclear magnetic resonance studies of banana fragments during ripening show an increase on the water transverse relaxation time (T2) and a decrease in water self-diffusion coefficient (D). As T(2) and D are normally directly correlated, we studied these two properties in intact bananas during ripening, in an attempt to rule out the effect of injury on the apparent discrepancies in the behavior of T(2) and D. RESULTS: The results show that injury in bananas causes a decrease in T2 of the water in vacuoles (T(2vac)). They also show that T(2vac) increased and D decreased during ripening, ruling out the injury effect. To explain the apparent discrepancies, we propose a new hypothesis for the increase in T2 values, based on the reduction of Fe3+ ions to Fe2+ by galacturonic acid, produced by the hydrolysis of pectin and a decrease in internal oxygen concentration during ripening. CONCLUSION: As injury alters T2 values it is necessary to use intact bananas to study relaxation times during ripening. The novel interpretation for the increase in T(2vac) based on reduction of Fe+3 and O2 concentration is an alternative mechanism to that based on the hydrolysis of starch in amyloplasts.