Overexpression of a Pea DNA Helicase (PDH45) in Peanut (Arachis hypogaea L.) Confers Improvement of Cellular Level Tolerance and Productivity Under Drought Stress

Abstract

Peanut, a major edible oil seed crop globally is predominantly grown under rainfed conditions and suffers yield losses due to drought. Development of drought-tolerant varieties through transgenic technology is a valid approach. Besides superior water relation traits like water mining, intrinsic cellular level tolerance mechanisms are important to sustain the growth under stress. To achieve this objective, the focus of this study was to pyramid drought adaptive traits by overexpressing a stress responsive helicase, PDH45 in the background of a genotype with superior water relations. PCR, Southern, and RT-PCR analyses confirmed stable integration and expression of the PDH45 gene in peanut transgenics. At the end of T₃ generation, eight transgenic events were identified as promising based on stress tolerance and improvement in productivity. Several transgenic lines showed stay-green phenotype and increased chlorophyll stability under stress and reduced chlorophyll retardation under etherel-induced simulated stress conditions. Stress-induced root growth was also substantially higher in the case of transformants. This was reflected in increased WUE (low Δ¹³C) and improved growth rates and productivity. The transgenics showed 17.2 and 26.75 % increase in yield under non-stress and stress conditions over wild type ascertaining the feasibility of trait pyramiding strategy for the development of drought-tolerant peanut.

Overexpression of Pea DNA Helicase 45 (PDH45) imparts tolerance to multiple abiotic stresses in chili (Capsicum annuum L.)

“…The expression of one of the potential stress responsive helicases, pea DNA helicase 45 ( PDH45 ) is induced by salinity, dehydration, wounding and low temperature, suggesting it to be a general factor involved in abiotic stress adaptation 22 . Consistent with this, over expression of PDH45 demonstrated enhanced abiotic stress tolerance 9, 18, 22, 24–27 in several crops.…”

“…Furthermore, transgenic technology through its ability to introduce genes from cross incompatible plant species is often considered as a precise technology for crop improvement. Among multiple single genes conferring abiotic stress tolerance, DNA and RNA helicases have proved their translational efficacy in multiple crops by improving tolerance to salinity and drought stress 9, 18, 22, 24–27 . DNA and RNA helicases, also known as molecular motors, are involved in myriad cellular processes of protein turnover and protection.…”

Expression of Pennisetum glaucum Eukaryotic Translational Initiation Factor 4A (PgeIF4A) Confers Improved Drought, Salinity, and Oxidative Stress Tolerance in Groundnut

“…The transgenic plants possessed efficient anti oxidative machinery which protected the plant cells from ROS induced oxidative damage. In other studies also increase in level of oxidative markers were reported when heterologous genes expressed in groundnut such as AtNHX (Asif et al, 2011), PHD45 (Manjulatha et al, 2014), AtNAC2 (Patil et al, 2014), MuNAC4 (Pandurangaiah et al, 2014). …”

“…The transgenic plantlets expressing PDH45 exhibited higher survival rate, shoot and root growth in comparison with wild type plants under mannitol and salt stress conditions. The improved lateral root formation could be due to expression of related target genes under stress conditions (Manjulatha et al, 2014). …”

“…A pea DNA helicase (PDH45) homologous to eIF4A when expressed in tobacco and rice imparted salt stress tolerance with minimal accumulation of sodium in transgenic plants (Sanan-Mishra et al, 2005; Nath et al, 2015). PDH45 gene when expressed in groundnut variety (K-134) showed high tolerance against moisture stress (Manjulatha et al, 2014). Multiple stress responsive genes such as OsAlfin (alfalfa zinc finger), PDH45 and PgHSF4 ( Pennisetum glaucum heat shock factor) simultaneously expressed in groundnut conferred tolerance to simulated drought stress and enhanced yield (Ramu et al, 2015).…”