Drought-responsive genes, late embryogenesis abundant group3 (LEA3) and vicinal oxygen chelate, function in lipid accumulation in Brassica napus and Arabidopsis mainly via enhancing photosynthetic efficiency and reducing ROS.

Yu Liang,Shaobo Ning,Kai Kang,Yongtai Yin,Lu Gan,Shuyao Song,Jinye Xiong,Shisheng Li,Senying Lai,Baoshan Wang,Maoteng Li,Jun Xiang,Lingzhi Xi,Jianwei Gu

doi:10.1111/pbi.13127

Abstract

SummaryDrought is an abiotic stress that affects plant growth, and lipids are the main economic factor in the agricultural production of oil crops. However, the molecular mechanisms of drought response function in lipid metabolism remain little known. In this study, overexpression (OE) of different copies of the drought response genes LEA3 and VOC enhanced both drought tolerance and oil content in Brassica napus and Arabidopsis. Meanwhile, seed size, membrane stability and seed weight were also improved in OE lines. In contrast, oil content and drought tolerance were decreased in the AtLEA3 mutant (atlea3) and AtVOC‐RNAi of Arabidopsis and in both BnLEA‐RNAi and BnVOC‐RNAi B. napus RNAi lines. Hybrids between two lines with increased or reduced expression (LEA3‐OE with VOC‐OE, atlea3 with AtVOC‐RNAi) showed corresponding stronger trends in drought tolerance and lipid metabolism. Comparative transcriptomic analysis revealed the mechanisms of drought response gene function in lipid accumulation and drought tolerance. Gene networks involved in fatty acid (FA) synthesis and FA degradation were up‐ and down‐regulated in OE lines, respectively. Key genes in the photosynthetic system and reactive oxygen species (ROS) metabolism were up‐regulated in OE lines and down‐regulated in atlea3 and AtVOC‐RNAi lines, including LACS9,LIPASE1,PSAN,LOX2 and SOD1. Further analysis of photosynthetic and ROS enzymatic activities confirmed that the drought response genes LEA3 and VOC altered lipid accumulation mainly via enhancing photosynthetic efficiency and reducing ROS. The present study provides a novel way to improve lipid accumulation in plants, especially in oil production crops.

Highlights

Drought is an important abiotic stress (Zhu, 2002) that can affect the morphological, physiological and biochemical characteristics of plants (Suzuki et al, 2014)
Significant drought stress can induce transcription of dehydration-responsive element-binding proteins (DREBs) in plants and activate genes that are involved in detoxification, water and ion movement and chaperone functions, including LEA (Shinozaki and Yamaguchi-Shinozaki, 2007; Wang et al, 2003; Xiong and Zhu, 2002; Yoshida et al, 2014)
As the LEA and VOC genes were both associated with drought stress, the drought tolerance of the LEA3-OE and VOC-OE transgenic lines was first validated under drought treatment (Figure S1C)

Summary

Introduction

Drought is an important abiotic stress (Zhu, 2002) that can affect the morphological, physiological and biochemical characteristics of plants (Suzuki et al, 2014). Significant drought stress can induce transcription of dehydration-responsive element-binding proteins (DREBs) in plants and activate genes that are involved in detoxification, water and ion movement and chaperone functions, including LEA (Shinozaki and Yamaguchi-Shinozaki, 2007; Wang et al, 2003; Xiong and Zhu, 2002; Yoshida et al, 2014). In this model, LEA genes are part of a category that could function in the protection of membranes and proteins. GLYI can use one molecule of glutathione (GSH) to convert MG to S-D-lactoylglutathione and functions in abiotic stress response (Mustafiz et al, 2014; Singla-Pareek et al, 2003)

Methods

Results

Discussion

Conclusion