Ya-Zhou Zhang1, Zhen-Zhen Wei1, Cai-Hong Liu1, Qing Chen1, Bin-Jie Xu1, Zhen-Ru Guo1, Yong-Li Cao1, Yan Wang1, Ya-Nan Han1, Chen Chen1, Xiang Feng1, Yuan-Yuan Qiao1, Lu-Juan Zong1, Ting Zheng1, Mei Deng1, Qian-Tao Jiang1, Wei Li 2, You-Liang Zheng1, Yu-Ming Wei1,*& Peng-Fei Qi1,*
1.Triticeae Research Institute, Sichuan Agricultural University, Chengdu, Sichuan 611130, China
2.Agronomy College, Sichuan Agricultural University, Chengdu, Sichuan 611130, China
* Corresponding author
These author contributed equally to this work.
Ya-Zhou Zhang, Zhen-Zhen Wei, Cai-Hong Liu, Qing Chen & Bin-Jie Xu
Scientific Reports 7, Article number: 46129 (2017)
doi:10.1038/srep46129
Abstract
Fusarium graminearum is the major causal agent of fusarium head blight in wheat, a serious disease worldwide. Linoleic acid isomerase (LAI) catalyses the transformation of linoleic acid (LA) to conjugated linoleic acid (CLA), which is beneficial for human health. We characterised a cis-12 LAI gene of F. graminearum (FGSG_02668; FgLAI12), which was downregulated by salicylic acid (SA), a plant defence hormone. Disruption of FgLAI12 in F. graminearum resulted in decreased accumulation of cis-9,trans-11 CLA, enhanced sensitivity to SA, and increased accumulation of LA and SA in wheat spikes during infection. In addition, mycelial growth, accumulation of deoxynivalenol, and pathogenicity in wheat spikes were reduced. Re-introduction of a functional FgLAI12 gene into ΔFgLAI12 recovered the wild-type phenotype. Fluorescent microscopic analysis showed that FgLAI12 protein was usually expressed in the septa zone of conidia and the vacuole of hyphae, but was expressed in the cell membrane of hyphae in response to exogenous LA, which may be an element of LA metabolism during infection by F. graminearum. The cis-12 LAI enzyme encoded by FgLAI12 is critical for fungal response to SA, mycelial growth and virulence in wheat. The gene FgLAI12 is potentially valuable for biotechnological synthesis of cis-9,trans-11 CLA.
