Mechanisms of Tolerance to Salinity in Banana:physiological, Biochemical,and Molecular Aspects

Abstract

-In the northeastern region of Brazil, saline soils are constraints to banana production, becoming necessary to understand the mechanisms of salt tolerance. two bananas genotypes, tap Maeo, tolerant, and Berlin, sensitive, were subjected to treatment with 50 mol m -3 Nacl or without salt. this study evaluated the effects of salt on the following physiological aspects: leaf area, content and distribution of Na + , membrane integrity, proton atPase activity. Besides, a search for differentially expressed genes was performed using the Differential Display technique. tap Maeo genotype showed the smallest reduction in leaf area, smaller accumulation of Na + and malondialdehyde (MDa), and higher activity of proton atPase activity. two sequences differentially expressed in the tolerant genotype, (Musa 07, Musa 23), shared a high degree of identity with the amino acid sequences of the genes SOS1 and SOS2, respectively. the clone Musa 10 was highly similar to amino acid sequence of the ascorbate peroxidase gene, and Musa 26, encodes the enzyme betaine aldehyde dehydrogenase. These significant biological markers indicate that salinity tolerance in banana involves at least two simultaneous mechanisms: the activation of the SOS pathway, increasing the extrusion of Na + , and the activation of antioxidative system, increasing the synthesis of aPX and betaine aldehyde dehydrogenase enzyme. Index terms: DDRt-PcR, leaf area, Musa, Na + , antioxidative system, SOS pathway. MECANISMOS DE TOLERÂNCIA À SALINIDADE EM BANANEIRA : ASPECTOS FISIOLÓGICOS, BIOQUÍMICOS E MOLECULARESRESUMO -Na região Nordeste do Brasil, solos salinos são restritivos à produção de banana, tornandose necessário compreender os mecanismos de tolerância de sal. Dois genótipos de banana, tap Maeo, tolerante, e Berlim, sensível, foram submetidos ao tratamento com 50 mol m-3 Nacl ou sem sal. este estudo avaliou os efeitos do sal sobre os seguintes aspectos fisiológicos: área foliar, conteúdo e distribuição de Na + , integridade da membrana, atividade da atPase. além disso, uma busca por genes diferencialmente expressos foi realizada usando a técnica Differential Display. O genótipo tap Maeo apresentou a menor redução na área foliar, menor acúmulo de Na + e malondialdeído (MDa) bem como maior atividade da H + atPase. Duas sequências diferencialmente expressas no genótipo tolerante (Musa 07, Musa 23) compartilham alto grau de identidade com as sequências de aminoácidos dos genes SOS1 e SOS2, respectivamente. O clone Musa 10 é muito semelhante à sequência de aminoácidos do gene da peroxidase do ascorbato, e o Musa 26 codifica a enzima aldeído betaína desidrogenase. Estes marcadores biológicos significativos indicam que a tolerância à salinidade em banana envolve pelo menos dois mecanismos simultâneos: a ativação da via SOS, aumentando a extrusão do Na + , e a ativação do sistema antioxidante, aumentando a síntese de aPX e da enzima aldeído betaína desidrogenase. Termos para indexação: área foliar, DDRt PcR, Musa, Na + , rota SOS, sistema antioxidativo. 1 (Pa...

Quick Method to Quantify the Potassium and Sodium Content Variation in Leaves of Banana Varieties

“…Silk and Mysore subgroups vary with segments of mosaics of AAA and ABB genomes in specific chromosomes. 34 The genomic locations and differences of sequences of saltresponsive genes were identified by Willadino et al 2 Genomic mosaic regions/genomes of AB and Silk and Mysore subgroups of AAB banana varieties were made available by Baurens et al 34 Salt tolerance genes 2 and their promoters can be explored in the future using the genomic resources of Baurens et al 34 to understand the mechanisms and differences in genes of sodium uptake and salt tolerance among banana varieties. Size and area of the banana leaf also decreases in salt-sensitive cultivars due to higher accumulation of sodium and chloride ions in lamina.…”

“…Size and area of the banana leaf also decreases in salt-sensitive cultivars due to higher accumulation of sodium and chloride ions in lamina. 2,11 Banana plants grown in saline or sodic saline soils or irrigated by salt water are likely to accumulate excess sodium ions in roots or leaf. 9,10 Sodium content of banana shoots in tissue culture gradually increases from 2520 to 6580 mg/L when the culture medium is supplemented with increasing levels (0 to 150 mM) of sodium chloride.…”

“…Potassium (K + ) and sodium (Na + ) are two important monovalent cations in banana plant nutrition 1 and salinity stress management. 2 The leaf and fruit of the banana plant are rich in potassium, hence K + is required in large quantities for optimal growth and yield of bananas. [3][4][5][6][7][8] K + forms 3 -4% of the cations in the dry weight of a banana plant.…”

“…12 Banana plants of salt-sensitive variety irrigated by saline water suffer from a reduction in leaf area and increase in foliar Na + content and reduced K + /Na + ratio. 2,13 Leaf K + /Na + ratio is also crucial in determining the performance of banana plants in saline-sodic soils. 1 Ash constitutes one-fifth of the leaf blade of the banana 14 plant and nearly 42% of it is water soluble extractive.…”

Biochemical, physiological and growth changes in response to in vitro salinity in sugarcane

“…Some other physiological and biochemical strategies to tolerate salt stress damage include selective ion accumulation or exclusion, changes in photosynthetic pathways, photosynthetic pigment degradation, decreased of stomatal conductance, changes in membrane structures, induction of hormones and enzymes antioxidants (ASHRAF; HARRIS, 2004;MUDGAL et al 2010;NAWAZ et al 2010;PARIDA;DAS, 2005). These aspects have already been studied in banana (WILLADINO et al, 2017), potato (TEIXEIRA;PEREIRA, 2007), rice (REDDY et al, 2017;CHA-UM et al, 2007), maize (HU et al, 2007), and in in vitro sugarcane crops under stress (AVINASH et al, 2012;KIRDMANEE, 2009;ERRABII et al, 2007;1650Biochemical, physiological… OLIVEIRA, L. A. R. et al PATADE et al, 2012PATADE et al, 2008;POONSAWAT et al, 2015). However, more detailed studies of these changes caused by stresses, associated with observation of the cells at the anatomical level are still scarce.…”