The long non-coding RNA GhlncRNA149.1 improves cotton defense response to aphid damage as a positive regulator

Abstract

Long non-coding RNAs (lncRNAs) play crucial roles in various plant biological regulatory processes and defense responses to all sorts of biotic and abiotic stresses. However, there are limited studies on the function and mechanism of lncRNAs in plant defense responses to phytophagous insects. In this research, a lncRNA GhlncRNA149.1 was identified from upland cotton (Gossypium hirsutum L.). Depending on the position relationship between lncRNA and mRNA, we identified CC-NBS-LRR family gene GhA01G0129 as the target gene of GhlncRNA149.1. Expression levels of GhlncRNA149.1 and its target gene GhA01G0129 were significantly down-regulated in cotton cotyledons upon cotton aphid infestation. The expression level of GhlncRNA149.1 was significantly down-regulated after the induction of methyl jasmonate and salicylic acid, whereas expression level of its target gene GhA01G0129 was significantly up-regulated. Overexpression of GhlncRNA149.1 in cotton cotyledons enhanced the tolerance of cotton plants to cotton aphid feeding. Expectedly, silencing GhlncRNA149.1 increased susceptibility of cotton plants to cotton aphids. The expression level of GhA01G0129, the target gene of GhlncRNA149.1, was significantly up-regulated in cotton plants overexpressing GhlncRNA149.1, and significantly down-regulated in cotton plants silencing GhlncRNA149.1. The activity and expression levels of antioxidant enzymes superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) were up-regulated in cotton plants transiently overexpressing GhlncRNA149.1, while opposite results were obtained in cotton plants silencing GhlncRNA149.1. In addition, similar results were obtained in the expression levels of phenylalanine ammonia-lyase (PAL), polyphenol oxidase (PPO), enhanced disease susceptibility 1 (EDS1) and non-expression of pathogenesis-related gene 1 (NPR1) in cotton plants transiently overexpressing GhlncRNA149.1 and silencing GhlncRNA149.1. These results collectively suggest that GhlncRNA149.1 improve the plant defense response to aphid attack, and thus has potential for enforcing cotton aphid prevention and control.