Abstract
Tobacco curly shoot virus (TbCSV) belongs to the genus Begomovirus of the family Geminiviridae, and causes leaf curling and curly shoot symptoms in tobacco and tomato crops. MicroRNAs (miRNAs) are pivotal modulators of plant development and host-virus interactions. However, the relationship between TbCSV infection and miRNAs accumulation has not been well investigated. The present study was conducted to analyze different expressions of miRNAs in Nicotiana benthamiana in response to the infection of TbCSV via small RNAs sequencing. The results showed that 15 up-regulated miRNAs and 12 down-regulated miRNAs were differentially expressed in TbCSV infected N. benthamiana, and nbe-miR167b-3p was down-regulated. To decipher the relationship between nbe-miR167b-3p expression and the accumulations of TbCSV DNA, pCVA mediation of miRNA overexpression and PVX based short tandem target mimic (STTM) were used in this study. It was found that overexpression of nbe-miR167b-3p attenuated leaf curling symptom of TbCSV and decreased viral DNA accumulation, but suppression of nbe-miR167b-3p expression enhanced the symptoms and accumulation of TbCSV. PRCP, the target gene of nbe-miR167b-3p, was silenced in plants using VIGS and this weakened the viral symptoms and DNA accumulation of TbCSV in the plants. Overall, this study clarified the effect of nbe-miR167b-3p on plant defense during TbCSV infection, and provided a framework to reveal the molecular mechanisms of miRNAs between plants and viruses.
Highlights
MicroRNAs are small RNAs with 20–25 nucleotides that play essential roles in plant biological processes by targeting complementary mRNAs for degradation or translation expression (Bologna and Voinnet, 2014; Cui et al, 2016)
They function in the response of plants to biotic and abiotic stresses (Wang et al, 2014; Tong et al, 2017), such as inducible expression of miR164 in Arabidopsis thaliana led to decreased NAC1 mRNA levels and reduced lateral root emergence (Guo et al, 2005); miRNA guided cleavage of TCP4 mRNA to control the morphogenesis of the leaves (Palatnik et al, 2003); Plants overexpressing osa-miR171b were less susceptible to Rice stripe virus (RSV) and virus symptoms were attenuated (Tong et al, 2017); In rice, osa-miR319b played an important role in plant response to cold stress possibly by targeting OsPCF6 and OsTCP21 (Wang et al, 2014)
RSV enhanced the accumulation of some miRNAs in rice (Du et al, 2011), Cucumber mosaic virus (CMV) FNY2b protein suppressed the function of miR159, inducing disease-like symptoms in host plants (Du et al, 2014); The synergistic infection of Maize chlorotic mottle virus (MCMV) and Sugarcane mosaic virus (SCMV) caused maize lethal necrosis, the down-regulation of miR159, miR393, and miR394 was involved in antiviral defense to synergistic infection (Xia et al, 2019)
Summary
MicroRNAs (miRNAs) are small RNAs with 20–25 nucleotides that play essential roles in plant biological processes by targeting complementary mRNAs for degradation or translation expression (Bologna and Voinnet, 2014; Cui et al, 2016). They function in the response of plants to biotic and abiotic stresses (Wang et al, 2014; Tong et al, 2017), such as inducible expression of miR164 in Arabidopsis thaliana led to decreased NAC1 mRNA levels and reduced lateral root emergence (Guo et al, 2005); miRNA guided cleavage of TCP4 mRNA to control the morphogenesis of the leaves (Palatnik et al, 2003); Plants overexpressing osa-miR171b were less susceptible to Rice stripe virus (RSV) and virus symptoms were attenuated (Tong et al, 2017); In rice, osa-miR319b played an important role in plant response to cold stress possibly by targeting OsPCF6 and OsTCP21 (Wang et al, 2014). It was found by our laboratory that different miRNAs can manipulated infected plants to show varied severity of disease symptoms (Du et al, 2020)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
