Premium
Downregulation of key genes involved in carbon metabolism in Medicago truncatula results in increased lipid accumulation in vegetative tissue
Author(s) -
Wijekoon Champa,
Singer Stacy D.,
Weselake Randall J.,
Petrie James R.,
Chen Guanqun,
Singh Surinder,
Eastmond Peter J.,
Acharya Surya N.
Publication year - 2020
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.1002/csc2.20124
Subject(s) - biology , medicago truncatula , shoot , botany , medicago , lipid metabolism , biochemistry , gene , symbiosis , genetics , bacteria
Abstract Alfalfa ( Medicago sativa L.) is the most widely grown perennial forage crop and is a close relative of the model diploid legume Medicago truncatula Gaertn. However, use of alfalfa leads to substantial greenhouse gas emissions and economic losses related to inefficiencies in rumen fermentation. The provision of supplemental lipids has been used as a strategy to mitigate these issues, but it is a costly approach. The ability to enhance lipid content within the vegetative tissues of alfalfa would therefore be very advantageous. As such, our aim was to assess and select gene candidates to increase total shoot lipid content in M. truncatula using a virus‐induced gene silencing (VIGS) approach. We targeted gene homologs of the SUGAR‐DEPENDANT 1 ( SDP1 ), ADP‐GLUCOSE‐PYROPHOSPHORYLASE SMALL SUBUNIT 1 ( APS1 ), TRIGALACTOSYLDIACYLGLYCEROL 5 ( TGD5 ), and PEROXISOMAL ABC TRANSPORTER 1 ( PXA1) in M. truncatula for silencing. Reduced target transcript levels were confirmed and changes of shoot lipid content and fatty acid composition were measured. Silencing of SDP1, APS1 , and PXA1 each resulted in significant increases in shoot total lipid content. Significantly increased proportions of α‐linolenic acid (18:3Δ 9 cis ,12 cis ,15 cis ) were observed, and stearic acid (18:0) levels significantly decreased in the total acyl lipids extracted from vegetative tissues of each of the M. truncatula silenced plants. In contrast, palmitic acid (16:0) levels were significantly decreased in only SDP1‐ and PXA1 ‐silenced plants. Genes of PXA1 and SDP1 would be ideal targets for mutation as a means of improving the quality of alfalfa to increase feed efficiency and minimize greenhouse gas emissions from livestock production in the future.