Associação entre Azospirillum brasilense e milho na tolerância ao estresse salino: uma abordagem antioxidante
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Data
2019-08-01
Autores
Checchio, Mirela Vantini [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Devido às intensas mudanças climáticas globais e atividades antropogênicas, a salinidade tornou-se uma das principais problemáticas limitantes à produção agrícola. Para lidar com essa problemática, o estudo de genótipos e cultivares que sejam tolerantes ao sal, bem como alternativas através de inoculantes torna-se cada vez mais necessário. O objetivo deste trabalho foi caracterizar a resposta antioxidante através da inoculação de Azospirillum brasilense em milho, e correlacionar a atividade destas enzimas ao aumento na capacidade da planta em tolerar o estresse ocasionado pela salinidade. Os tratamentos foram formados pela combinação de cloreto de sódio (0 e 100 mM de NaCl) via água de irrigação e ausência e presença do inóculo de A. brasilense, sendo o experimento conduzido inteiramente casualizado, com quatro repetições Os resultados demonstraram diferentes respostas de acordo com as análises de peroxidação lipídica (MDA), quantificação de nitrogênio (N) e sódio (Na+), massa seca (MS) e atividades enzimáticas, como superóxido dismutase (SOD, EC 1.15.1.1), glutationa redutase (GR, EC 1.6.4.2), guaiacol peroxidase (GPOX, EC 1.11.1.7) e glutationa peroxidase (GSH-PX, EC. 1.11.1.9). Os resultados mostraram que 100 mM de NaCl ocasionou peroxidação lipídica, com consequente aumento do teor de MDA. Entretanto, com a presença da bactéria nesta condição, o teor de MDA foi reduzido, houve aumento do acúmulo de N e as enzimas apresentaram diferenças significativas entre si, com aumentos significativos para GSH-PX e GPOX. Nossos dados sugerem que a presença de A. brasilense no milho sob estresse salino pode conferir tolerância a planta e que esta tolerância está relacionada ao sistema de defesa antioxidante, principalmente de GSH-PX e GPOX.
Due to intense global climate change and anthropogenic activities, salinity has become one of the main problems limiting agricultural production. To deal with this problem, the study of genotypes and cultivars that are salt tolerant and also alternatives through inoculants becomes increasingly necessary. The main of this work was to characterize an antioxidant response through the inoculation of Azospirillum brasilense in maize and to correlate the activity of the enzymes with the salt-stress tolerance. The experiment was carried out in a completely randomized design with four replications. The treatments were performed by combination of sodium chloride (0 and 100 mM NaCl) through irrigation water and absence and presence of A. brasilense inoculation. Overall results showed different responses according to lipid peroxidation (MDA), nitrogen (N) and Na+ contents, dry mass (DM) and enzymatic activities, such as superoxide dismutase (SOD, EC 1.15.1.1), glutathione reductase (GR, EC 1.6.4.2), guaiacol peroxidase (GPOX, EC 1.11.1.7) and glutathione peroxidase (GSH-PX, EC 1.11.1.9). The results showed were that 100 mM NaCl caused lipid peroxidation with consequent increases in MDA content. However, MDA content was reduced and antioxidant enzymes demonstrated significant differences in the presence of the bacteria. Our data suggest that A. brasilense may confer plant tolerance in maize to salt stress and acquired tolerance can be related to the antioxidant system, mainly GSH-PX and GPOX.
Due to intense global climate change and anthropogenic activities, salinity has become one of the main problems limiting agricultural production. To deal with this problem, the study of genotypes and cultivars that are salt tolerant and also alternatives through inoculants becomes increasingly necessary. The main of this work was to characterize an antioxidant response through the inoculation of Azospirillum brasilense in maize and to correlate the activity of the enzymes with the salt-stress tolerance. The experiment was carried out in a completely randomized design with four replications. The treatments were performed by combination of sodium chloride (0 and 100 mM NaCl) through irrigation water and absence and presence of A. brasilense inoculation. Overall results showed different responses according to lipid peroxidation (MDA), nitrogen (N) and Na+ contents, dry mass (DM) and enzymatic activities, such as superoxide dismutase (SOD, EC 1.15.1.1), glutathione reductase (GR, EC 1.6.4.2), guaiacol peroxidase (GPOX, EC 1.11.1.7) and glutathione peroxidase (GSH-PX, EC 1.11.1.9). The results showed were that 100 mM NaCl caused lipid peroxidation with consequent increases in MDA content. However, MDA content was reduced and antioxidant enzymes demonstrated significant differences in the presence of the bacteria. Our data suggest that A. brasilense may confer plant tolerance in maize to salt stress and acquired tolerance can be related to the antioxidant system, mainly GSH-PX and GPOX.
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Palavras-chave
Estresse abiótico, Salinidade dos solos, Bactéria diazotrófica, Milho, Abiotic stress, Diazotrophic bacterias, Salt tolerance induction