RESUMO
Conferring drought resistant traits to crops is one of the major aims of current breeding programs in response to global climate changes. We previously showed that exogenous application of acetic acid to roots of various plants could induce increased survivability under subsequent drought stress conditions, but details of the metabolism of exogenously applied acetic acid, and the nature of signals induced by its application, have not been unveiled. In this study, we show that rice rapidly induces jasmonate signaling upon application of acetic acid, resulting in physiological changes similar to those seen under drought. The major metabolite of the exogenously applied acetic acid in xylem sap was determined as glutamine-a common and abundant component of xylem sap-indicating that acetic acid is not the direct agent inducing the observed physiological responses in shoots. Expression of drought-responsive genes in shoot under subsequent drought conditions was attenuated by acetic acid treatment. These data suggest that acetic acid activates root-to-shoot jasmonate signals that partially overlap with those induced by drought, thereby conferring an acclimated state on shoots prior to subsequent drought.
Assuntos
Ácido Acético/farmacologia , Produtos Agrícolas/metabolismo , Ciclopentanos/metabolismo , Secas , Oryza/metabolismo , Oxilipinas/metabolismo , Reguladores de Crescimento de Plantas/metabolismo , Raízes de Plantas/metabolismo , Transdução de Sinais/efeitos dos fármacos , Aclimatação/efeitos dos fármacos , Aclimatação/genética , Produtos Agrícolas/genética , Regulação da Expressão Gênica de Plantas , Glutamina/metabolismo , Oryza/genética , Melhoramento Vegetal/métodos , Raízes de Plantas/genética , Brotos de Planta/genética , Brotos de Planta/metabolismo , Transdução de Sinais/genética , Estresse Fisiológico/efeitos dos fármacos , Estresse Fisiológico/genética , Transcriptoma/efeitos dos fármacos , Xilema/metabolismoRESUMO
Rice seedlings (Oryza sativa) that have died from drought cannot be rescued by watering afterward, but pre-treatment with exogenous acetic acid enabled the plants to produce shoots again after being watered (hereinafter referred to as "drought resilience"). To elucidate the metabolism of acetic acid, we treated rice plants with 13C-labeled acetic acid and traced 13C-labeled metabolites using LC-MS and 13C-NMR techniques. The LC-MS and 13C-NMR spectral data of the root extracts indicated that the acetic acid treatment was absorbed into the plants and then was metabolized to gamma-aminobutyric acid (GABA) by glutamic acid decarboxylase (GAD). GABA accumulation in the roots took place in advance of that in the shoots, and the survival rate against drought stress increased in proportion to the amount of GABA accumulated in the shoots. Therefore, GABA accumulation in shoots may be a key step in drought resilience induced by the acetic acid treatment.
