Open AccessRNA‐dependent RNA polymerase 1 delays the accumulation of viroids in infected plants
Author(s) -
Li Shuai,
Zhang Zhixiang,
Zhou Changyong,
Li Shifang
Publication year - 2021
Publication title -
molecular plant pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.945
H-Index - 103
eISSN - 1364-3703
pISSN - 1464-6722
DOI - 10.1111/mpp.13104
Subject(s) - viroid , potato spindle tuber viroid , biology , nicotiana benthamiana , virology , rna silencing , rna , plant virus , rna interference , gene , virus , genetics
RNA‐dependent RNA polymerase 1 (RDR1) is essential for plant antiviral defence, but its role in plant defence against viroid infection remains unknown. The present study aimed to identify the function and mechanism of RDR1 in plant resistance to viroid infection. Overexpression of Nicotiana tabacum RDR1 ( NtRDR1 ) delayed the accumulation of potato spindle tuber viroid (PSTVd) genomic RNA and PSTVd‐derived small RNA (sRNA) in Nicotiana benthamiana plants at the early invasion stage, but not in the late stage of infection. Conversely, virus‐induced gene silencing of tomato RDR1 ( SlRDR1a ) increased the susceptibility to PSTVd infection (increased viroid accumulation). Salicylic acid (SA) pretreatment induced SlRDR1a expression and enhanced the defence against PSTVd infection in tomato plants. Our study demonstrated that RDR1 is involved in SA‐mediated defence and restricts the early systemic invasion by PSTVd in plants. The decreased PSTVd accumulation in N . benthamiana was not caused by efficient accumulation of PSTVd sRNAs. These results deepen our understanding of the mechanism of RDR1 in plant defence responses to viroid attack.