Arsenate induced differential response in rice genotypes.

To study the differential response in two rice genotypes (PB1 and IR-64), hydroponically grown 14 days old plants were exposed to 50, 150 and 300µM As(V) for 24 and 96h. Accumulation of As was not significantly higher in PB1 variety except at higher concentration (300μM) and duration (96h), but up regulation of gene transcripts were higher as compared to IR-64. Inhibition in seed germination, root-shoot length, chlorophyll and protein content was observed in both varieties with increasing concentration and exposure time. PB1 variety was found more capable to detoxify As(V) through induction of antioxidant defense system and other stress related parameters (cysteine, proline content). SDS-PAGE and semi quantitative RT-PCR analysis showed significant changes in protein profile and gene expression analysis. The results suggests that various studied parameters and transcripts accumulation showed a combinatorial type of tolerance mechanism in PB1 variety to provide better protection against As(V) stress.