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Article|01 Aug 2019|OPEN
A novel miRNA negatively regulates resistance to Glomerella leaf spot by suppressing expression of an NBS gene in apple
Yi Zhang1 , Qiulei Zhang1 , Li Hao1 , Shengnan Wang1 , Shengyuan Wang1 , Wenna Zhang1 , Chaoran Xu1 , Yunfei Yu1 and Tianzhong Li,1 ,
1Laboratory of Fruit Cell and Molecular Breeding, China Agricultural University, Beijing 100193, China
*Corresponding author. E-mail: litianzhong1535@163.com

Horticulture Research 6,
Article number: 93 (2019)
doi: https://doi.org/10.1038/s41438-019-0175-x
Views: 1062

Received: 07 Feb 2019
Revised: 13 May 2019
Accepted: 15 Jun 2019
Published online: 01 Aug 2019

Abstract

Glomerella leaf spot (GLS) of apple (Malus×domestica Borkh.), caused by Glomerella cingulata, is an emerging fungal epidemic threatening the apple industry. Little is known about the molecular mechanism underlying resistance to this devastating fungus. In this study, high-throughput sequencing technology was used to identify microRNAs (miRNAs) involved in GLS resistance in apple. We focused on miRNAs that target genes related to disease and found that expression of a novel miRNA, Md-miRln20, was higher in susceptible apple varieties than in resistant ones. Furthermore, its target gene Md-TN1-GLS exhibited the opposite expression pattern, which suggested that the expression levels of Md-miRln20 and its target gene are closely related to apple resistance to GLS. Furthermore, downregulation of Md-miRln20 in susceptible apple leaves resulted in upregulation of Md-TN1-GLS and reduced the disease incidence. Conversely, overexpression of Md-miRln20 in resistant apple leaves suppressed Md-TN1-GLS expression, with increased disease incidence. We demonstrated that Md-miRln20 negatively regulates resistance to GLS by suppressing Md-TN1-GLS expression and showed, for the first time, a crucial role for miRNA in response to GLS in apple.