Expression Analysis of OsWRKY11 and OsNAC2 Genes in New Malaysian Drought-tolerance Rice Cultivar MR303

Abstract

Local drought-tolerant rice variety MR303 (Oryza sativa spp. Indica) has higher tolerance towards abiotic stress while maintaining its high yield and grain quality. Expression of OsWRKY11 has shown to be a positive modulator while OsNAC2 is a negative modulator for drought-tolerance in Oryza sativa spp. Japonica. However, these transcription factor (TF) genes regulation are species-specific and its regulation may differ in our local rice variety. Thus, our study aimed to identify the relative expression of these genes and its effects on plant morphology and drought-tolerance capabilities. Our results on relative expression of OsWRKY11 in the MR303 rice variety showed that under drought stress, this gene was highly expressed. This result was similar to previous findings in Oryza sativa spp. Japonica. However, for OsNAC2 gene expression, our results contradict with previous findings where under drought stress, this gene was also highly expressed instead of downregulated. These results suggest that our local rice variety may have different gene regulation under drought stress compared to other rice varieties. Proline assay showed that proline contents in drought-treated plant has increased 10 times compared to control which associated with drought-tolerance activities. Further studies may be conducted to gain better understanding on the roles of these genes in regulating drought-responsive genes in the local variety.