Proline metabolic dynamics and implications in drought tolerance of peanut plants

FURLAN, ANA LAURA; BIANUCCI, ELIANA; GIORDANO, WALTER; CASTRO, STELLA; BECKER, DONALD F.

PLANT PHYSIOLOGY AND BIOCHEMISTRY

ELSEVIER FRANCE-EDITIONS SCIENTIFIQUES MEDICALES ELSEVIER

Lugar: Paris; Año: 2020 vol. 151 p. 566 - 578

0981-9428

Proline accumulation and metabolism are associated with mechanisms of abiotic stress avoidance in plants.Proline accumulation generally improves osmotic stress tolerance whereas proline metabolism can have varyingeffects from ATP generation to the formation of reactive oxygen species. To further understand the roles ofproline in stress protection, two peanut cultivars with contrasting tolerance to drought were examined bytranscriptional and biochemical analyses during water stress. Plants exposed to polyethylene glycol had diminishedrelative water content and increased proline content; while, only the drought sensitive plants, cultivarGranoleico, showed lipid oxidative damage (measured as thiobarbituric acid reactive substances). The expressionof proline biosynthesis genes (P5CS1, P5CS2a, P5CS2b, P5CR) was increased in both cultivars upon exposureto water stress. However, the relative expression of proline catabolism genes (ProDH1, ProDH2) wasincreased only in the sensitive cultivar during stress. Exogenous addition of proline and the proline analoguethiazolidine-4-carboxylic acid (T4C), both substrates of proline dehydrogenase, was also used to exacerbate andidentify plant responses. Pretreatment of plants with T4C induced unique changes in the drought tolerant EC-98cultivar such as higher mRNA levels of proline biosynthetic and catabolic ProDH genes, even in the absence ofwater stress. The increased levels of ProDH gene expression, potentially associated with higher T4C conversion tocysteine, may contribute to the tolerant phenotype.