MicroRNA528 Affects Lodging Resistance of Maize by Regulating Lignin Biosynthesis under Nitrogen-Luxury Conditions

作     者：Qing Sun Xiaogang Liu Juan Yang Wenwen Liu Qingguo Du Hongqiu Wang Chunxiang Fu Wen-Xue Li 

作者机构：National Engineering Laboratory for Crop Molecular Breeding Institute of Crop Science Chinese Academy of Agricultural Sciences Beijing 100081 China Shandong Provincial Key Laboratory of Energy Genetics Qingdae Engineering Research Center of Biomass Resources and Environment and CAS Key Laboratory of Biofuels Qingdao Institute of Bioenergy and Bioprocess Technology Chinese Academy of Sciences Qingdao 266101 China 

出 版 物：《Molecular Plant》 (分子植物（英文版）)

年 卷 期：2018年第11卷第6期

页      面：806-814页

核心收录：

学科分类：0710[理学-生物学] 083002[工学-环境工程] 0830[工学-环境科学与工程（可授工学、理学、农学学位）] 08[工学] 09[农学] 0901[农学-作物学] 0902[农学-园艺学] 

基　　金：supported by the National Key Research and Development Program of China the Ministry of Agriculture of China for Transgenic Research the Agricultural Science and Technology Innovation Program of CAAS to W.-X.L 

主　　题：maize nitrogen ZmmiR528 ZmLACs lodging resistance 

摘      要：Lodging under nitrogen （N）-Iuxury conditions substantially reduces crop yield and seed quality. However, the molecular mechanisms of plant lodging resistance remain largely unclear, especially in maize. We report here that the expression of ZmmiR528, a monocot-specific microRNA, is induced by N luxury but reduced by N deficiency. We show by the thioacidolysis and acetyl bromide analysis that N luxury signifi- cantly reduces the generation of H, G, and S monomers of the lignin as well as its total content in maize shoots. We further demonstrate that ZmLACCASE3 （ZmLAC3） and ZmLACCASE5 （ZmLAC5）, which encode the copper-containing laccases, are the targets of ZmmiR528. In situ hybridization showed that ZmmiR528 is mainly expressed in maize vascular tissues. Knockdown of ZmmiR528 or overexpression of ZmLAC3 significantly increased the lignin content and rind penetrometer resistance of maize stems. In contrast, transgenic maize plants overexpressing ZmmiR528 had reduced lignin content and rind penetrometer resistance and were prone to lodging under N-luxury conditions. RNA-sequencing analysis revealed that ZmPAL7 and ZmPAL8 are upregulated in transgenic maize lines downregulating ZmmiR528. Under N-lux- ury conditions, the expression levels of ZmPALs were much higher in ZmmiR528-knockdown lines than in the wild type and transgenic maize lines overexpressing ZmmiR528. Taken together, these results indicate that, by regulating the expression of ZmLAC3 and ZmLAC5, ZmmiR528 affects maize lodging resistance un- der N-luxury conditions.