0023-6152

AA00697606

4103697

This study was conducted to investigate the expression of genes related to proline metabolism under drought stress and re–watering conditions in two rice varieties DA8 (drought tolerant) and Malagkit Pirurutong (drought sensitive). The results confirmed that proline was higher accumulated under drought stress than control in both varieties. Under the same drought severity, tolerant variety (DA8) accumulated higher proline than sensitive variety (Malagkit Pirurutong). The expression of P5CS1 and P5CS2, responsible for the synthesis of P5CS enzyme, which catalyzes the first step of the proline synthesis, were induced by drought stress. DA8 showed higher expressions of P5CS2, P5CR (which codes enzyme converting P5C into proline) and OsOAT (involve in proline synthesis through ornithine) than those in Malagkit Pirurutong under severe drought condition. The results suggested that high expression of P5CS1, P5CS2, P5CR and OsOAT genes, particularly under severe drought condition, were in line with the high accumulation of proline. At 4 days after re–watering, proline was quickly degraded due to the decreased expression of synthesis genes and the increased expression of P5CDH, a gene related to proline degradation after re–watering.