The Study On Function Of Tomato LncRNA39026 In Disease Resistance

Tomato(Solanum lycopersicum),as a kind of nutritious and widely-cultivated Solanaceae,is popular.Late blight,caused by Phytophthora infestans,leads to huge economic loss in tomato production,however,traditional chemical control could result in environmental pollution and so on.Therefore,it's necessary to identify the key factors and study tomato resistance mechanisms against P.infestans to breeding for disease-resistance cultivars.Recently,with the development of sequencing technology,it has been indicated that lncRNAs(long non-coding RNAs)as a new regulator,could participate in many biological processes,including plant defense to pathogens infection.In this study,a resistance-related lncRNA,lncRNA39026 was isolated in tomato plants infected with P.infestans.Then we clarify its function by biotechnology:First,we cloned lncRNA39026 from tomato cDNA and analyzed the endogenous target mimicry(eTM)sites of miRNAs.The results showed that lncRNA39026 sequence contained the eTM site of miR168 a,supposed that lncRNA39026 could function through decoying miR168 a to modulate the expression of SlAGO1.Then we analyzed the expression pattern of lncRNA39026,miR168 a and its targets gene during tomato infected by P.infestans,and the results suggested that all of them responded to P.infestans infection and the expression level of lncRNA39026 displays a negative correlation with the expression level of miR168 a and a positive correlation with the expression levels of SlAGO1 gene,suggested that lncRNA39026 responsed to P.infestans infection through decoying miR168 a to modulate the expression of SlAGO1.Secondly,to further explore the function of lncRNA39026,we overexpressed and silenced lncRNA39026 in tomato by genetic engineering technology and analyzed their resistance against P.infestans.The results showed that tomato plants in which lncRNA39026 was transiently overexpressed displayed enhanced resistance to P.infestans,decreased the level of miR168 a,increased the level of SlAGO1 and induced the level of resistance-related genes,while the resistance was impaired,the level of miR168 a was increased,the level of SlAGO1 was decreased and the level of resistance-related genes was reduced after lncRNA39026 silencing.Finally,we overexpressed lncRNA39026 in tobacco to verify the interaction between lncRNA39026 and miR168 a,and as a result,the expression of miR168 a was down-regulated,the expression of NtAGO1 was up-regulated,and the resistance to Fusarium wilt was enhanced,suggested lncRNA39026 has an effected on tobacco resistance to Fusarium wilt by decoying miR168 a.In conclusion,we proposed that lncRNA39026 participated in plant defense response to pathogens positively via severing as an eTM for miR168 a and inducing the expression of resistance-related genes.