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Front. Plant Sci. | doi: 10.3389/fpls.2018.01869

Overexpression of ß-Ketoacyl Co-A synthase1 gene Improves Tolerance of Drought Susceptible Groundnut (Arachis hypogaea L.) Cultivar K-6 by Increased Leaf Epicuticular Wax Accumulation

  • 1Sri Krishnadevaraya University, India

Drought is one of the major environmental constraints affecting the crop productivity worldwide. One of the agricultural challenges today is to develop plants with minimized water utilization and reduced water loss in adverse environmental conditions. Epicuticular waxes play a major role in minimizing water loss. Epicuticular wax covers aerial plant parts and also prevent non-stomatal water loss by forming the outermost barrier from the surfaces. Epicuticular wax content variation was found to be affiliated with the drought tolerance of groundnut cultivars. In the current study, a fatty acid elongase gene, KCS1, which catalyzes a rate-limiting step in the epicuticular wax biosynthesis was isolated from drought tolerant cultivar K-9 and overexpressed in drought-sensitive groundnut cultivar (K6) under the control of a CaMV35S constitutive promoter. Transgenic groundnut plants overexpressing AhKCS1 exhibited normal growth and displaying greenish dark shiny appearance. Environmental scanning electron microscopy (ESEM) revealed the excess of epicuticular wax crystal depositions on the transgenic plant leaves compared to non-transgenic wild type plants. The findings were further supported by Gas Chromatography – Mass Spectroscopic analysis (GC-MS) that revealed enhanced levels of fatty acids, secondary alcohols, primary alcohols, aldehydes, alkanes, and ketones in transgenics compared to wild types. The AhKCS1 overexpressing transgenic groundnut plants exhibited an increase in the cuticular wax content, reduction of water loss, lower membrane damage, decreased MDA content and high proline content compared to that of non-transgenic groundnut plants. Our findings suggest that the AhKCS1 gene plays a major role in combating drought stress by preventing non-stomatal water loss in drought-sensitive groundnut cultivar (K-6).

Keywords: Groundnut, Drought stress, AhKCS1, Epicuticular wax, non-stomatal water loss, transgenic plants

Received: 28 Jul 2018; Accepted: 04 Dec 2018.

Edited by:

James Lloyd, Stellenbosch University, South Africa

Reviewed by:

John C. Cushman, University of Nevada, Reno, United States
Zhanguo Xin, Agricultural Research Service, United States Department of Agriculture, United States  

Copyright: © 2018 Lokesh, Venkatesh, kiranmai, KUMAR, Reddy, Anthony Johnson, Pandurangaiah and Sudhakar. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Prof. Chinta Sudhakar, Sri Krishnadevaraya University, Anantapur, Andhra Pradesh, 124001, Andhra Pradesh, India, chintasudhakar@yahoo.com