Ectopic expression of DnaJ type-I protein homolog of Vigna aconitifolia (VaDJI) confers ABA insensitivity and multiple stress tolerance in transgenic tobacco plants

Ranjana Gautam; Rajesh Kumar Meena; Sakshi Rampuria; Pawan Shukla; P B Kirti

doi:10.3389/fpls.2023.1135552

Ectopic expression of DnaJ type-I protein homolog of Vigna aconitifolia (VaDJI) confers ABA insensitivity and multiple stress tolerance in transgenic tobacco plants

Front Plant Sci. 2023 Apr 19:14:1135552. doi: 10.3389/fpls.2023.1135552. eCollection 2023.

Authors

Ranjana Gautam^{1

2}, Rajesh Kumar Meena¹, Sakshi Rampuria¹, Pawan Shukla³, P B Kirti¹

Affiliations

¹ Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Hyderabad, Telangana, India.
² Department of Life Sciences and Biotechnology, Chhatrapati Shahu Ji Maharaj University, Kanpur, Uttar Pradesh, India.
³ Seri-Biotech Research Laboratory, Central Silk Board, Bangalore, India.

Abstract

Reduced crop productivity results from altered plant physiological processes caused by dysfunctional proteins due to environmental stressors. In this study, a novel DnaJ Type-I encoding gene, VaDJI having a zinc finger motif in its C-terminal domain was found to be induced early upon treatment with heat stress (within 5 min) in a heat tolerant genotype of Vigna aconitifolia RMO-40. VaDJI is induced by multiple stresses. In tobacco, ectopic expression of VaDJI reduced ABA sensitivity during seed germination and the early stages of seedling growth of transgenic tobacco plants. Concomitantly, it also improved the ability of transgenic tobacco plants to withstand drought stress by modulating the photosynthetic efficiency, with the transgenic plants having higher F_v/F_m ratios and reduced growth inhibition. Additionally, transgenic plants showed a reduced build-up of H₂O₂ and lower MDA levels and higher chlorophyll content during drought stress, which attenuated cell damage and reduced oxidative damage. An analysis using the qRT-PCR study demonstrated that VaDJI overexpression is associated with the expression of some ROS-detoxification-related genes and stress-marker genes that are often induced during drought stress responses. These findings suggest a hypothesis whereby VaDJI positively influences drought stress tolerance and ABA signalling in transgenic tobacco, and suggests that it is a potential gene for genetic improvement of drought and heat stress tolerance in crop plants.

Keywords: DnaJ; VaDJI; drought stress; gene expression; heat stress; photosynthetic efficiency; tobacco.

Grants and funding

This work was conducted without any grant. The work was carried out by the candidates UGC-RGNF fellowship contingency recieved for doing Ph.D. work which was around 12000/- per annum for initial two years and 25000/- per annum for next three years.