Heterologous expression of PDH47 confers drought tolerance in indica rice

Abstract

In response to challenge of producing rice plants tolerant to drought stress, Pea DNA Helicase 47 (PDH47) from Pisum sativum under the control of constitutive 35S CaMV promotor was introduced into indica rice cultivar ASD16 mediated through Agrobacterium tumefaciens using immature embryos as explant. PCR positive transgenic rice lines showed varied levels of PDH47 transcripts as evident by semi-quantitative reverse transcription PCR (RT-PCR). Copy number of the transgene was determined through quantitative PCR (qPCR) analysis. T2 transgenic lines showed upregulation of PDH47 transcripts both in leaf and root tissues after 30 days of drought stress treatment in pots as evident by quantitative reverse transcription PCR (qRT-PCR). The upregulation of PDH47 transcripts during drought stress correlated with increased accumulation of osmolytes like proline, increased relative water content and decreased accumulation of hydrogen peroxide (H2O2). T2 transgenic lines also showed enhanced tolerance to drought compared to wild type rice after withdrawal of water for 30 days. Further, the heterologous expression of PDH47 regulated several endogenous stress-responsive genes in transgenic rice during drought stress. To the best of our knowledge, we are reporting for the first time the involvement of PDH47 transgene imparting drought tolerance in transgenic rice, demonstrating its potential role in crop improvement.