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Article|01 Mar 2021|OPEN
Identification of long noncoding RNAs involved in resistance to downy mildew in Chinese cabbage
Bin Zhang1,2,3, Tongbing Su1,2,3, Peirong Li1,2,3, Xiaoyun Xin1,2,3, Yunyun Cao1,2,3, Weihong Wang1,2,3, Xiuyun Zhao1,2,3, Deshuang Zhang1,2,3, Yangjun Yu1,2,3, Dayong Li1,2,3, Shuancang Yu2,3,1, & Fenglan Zhang2,3,1,
1Beijing Vegetable Research Center (BVRC), Beijing Academy of Agriculture and Forestry Sciences (BAAFS), 100097 Beijing, China
2Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (North China), Ministry of Agriculture, 100097 Beijing, China
3Beijing Key Laboratory of Vegetable Germplasm Improvement, 100097 Beijing, China

Horticulture Research 8,
Article number: 44 (2021)
doi: 10.1038/hortres.2021.44
Views: 279

Received: 12 Oct 2020
Revised: 14 Dec 2020
Accepted: 17 Dec 2020
Published online: 01 Mar 2021

Abstract

Brassica downy mildew, a severe disease caused by Hyaloperonospora brassicae, can cause enormous economic losses in Chinese cabbage (Brassica rapa L. ssp. pekinensis) production. Although some research has been reported recently concerning the underlying resistance to this disease, no studies have identified or characterized long noncoding RNAs involved in this defense response. In this study, using high-throughput RNA sequencing, we analyzed the disease-responding mRNAs and long noncoding RNAs in two resistant lines (T12–19 and 12–85) and one susceptible line (91–112). Clustering and Gene Ontology analysis of differentially expressed genes (DEGs) showed that more DEGs were involved in the defense response in the two resistant lines than in the susceptible line. Different expression patterns and proposed functions of differentially expressed long noncoding RNAs among T12–19, 12–85, and 91–112 indicated that each has a distinct disease response mechanism. There were significantly more cis- and trans-functional long noncoding RNAs in the resistant lines than in the susceptible line, and the genes regulated by these RNAs mostly participated in the disease defense response. Furthermore, we identified a candidate resistance-related long noncoding RNA, MSTRG.19915, which is a long noncoding natural antisense transcript of a MAPK gene, BrMAPK15. Via an agroinfiltration-mediated transient overexpression system and virus-induced gene silencing technology, BrMAPK15 was indicated to have a greater ability to defend against pathogens. MSTRG.19915-silenced seedlings showed enhanced resistance to downy mildew, probably because of the upregulated expression of BrMAPK15. This research identified and characterized long noncoding RNAs involved in resistance to downy mildew, laying a foundation for future in-depth studies of disease resistance mechanisms in Chinese cabbage.