GA Mediated OsZAT-12 Expression Improves Salt Resistance of Rice

Abiotic stress prevents plants from absorbing available nutrients resulting in yield loss and soil contamination. Growth regulators like gibberellic acid (GA) may improve plant growth under stress conditions. This study was conducted to evaluate the role of GA on the rice performance under saline conditions and to investigate its effects on regulatory gene expression by GA-mediated seed priming. Seeds of rice variety KSK 282 were primed in GA solution (0, 50, 100 and 150 ppm) and grown under different salt (NaCl) concentrations (0, 50, 100 and 150 mM). Increase in salt concentration led to decrease in rice growth. GA priming reversed the negative effects of salt stress and enhanced different growth attributes like germination, seedling growth and weight, while decreased the concentration of toxic ions such as Na+ in some treatments. However, GA priming was not very effective on Chlorophyll a, b (Chl-a, Chl-b) and total carotene contents. Reverse transcription polymerase chain reaction (RT-PCR) approach was used to study the effect of GA-mediated seed priming on the expression of two stress responsive genes, OsZat 12-1 (LOC_Os01g62130 also called ZOS1-14 - C2H2 zinc finger protein) and OsZat 12-9 (LOC_Os01g62190 also called ZOS1-15 - C2H2 zinc finger protein). There was no or very low expression of OsZat 12-1 and OsZat 12-9 in hydroprimed seeds under all salt stress conditions tested, while induction of gene expression was observed for plants raised from GA primed seeds under salt stress. In conclusion, GA regulated the growth at early stages of rice life cycle by inducing regulatory genes expression; therefore it is noteworthy that while studying salinity factor, the induction of genetic determinants (genes) by plant growth regulators should also be considered. (C) 2016 Friends Science Publishers