Development of marker‐free rice with stable and high resistance to rice black‐streaked dwarf virus disease through RNA interference

Abstract

The rice black‐streaked dwarf virus (RBSDV) disease causes severe rice yield losses in Asia. RNA interference (RNAi) has been widely applied to develop antiviral varieties in plants. So far, only a few studies reported the application of RNAi in rice against RBSDV and most of them are lack of enough data to support its breeding potential, which limited the progress on developing RBSDV‐resistant variety. In this study, we generated three RNAi constructs to specifically target three RBSDV genes (S1, S2 and S6), respectively. We confirmed that RNAi targeting RBSDV S6 conferred rice with almost full immunity to RBSDV through phenotyping test in eight consecutive years in both artificial inoculation and field trials, while RNAi of S1 or S2 only leads to partially increased resistance. The S6RNAi was also found conferring strong resistance to southern rice black‐streaked dwarf virus (SRBSDV), a novel species closely related to RBSDV that outbroke recently in Southern China. In particular, no adverse effects on agronomical and developmental traits were found in S6RNAi transgenic lines. The marker‐free transgenic lines with S6RNAi, driven by either maize ubiquitin‐1 promoter or rice rbcS green tissue expression promoter, in elite rice background should have great potential in breeding of resistant varieties to both RBSDV and SRBSDV and provide a basis for further safety evaluation and commercial application.

An aspartic protease 47 causes quantitative recessive resistance to rice black‐streaked dwarf virus disease and southern rice black‐streaked dwarf virus disease

“…Thus, qRBSDV6‐1 was detected in both the field and artificial inoculation tests by using different subpopulations. Interestingly, this QTL also overlaps with the QTL for RBSDVD resistance in previous studies (Zheng et al ., 2012; Zhang et al ., 2016; Feng et al ., 2019, 2020; Xiao et al ., 2019), suggesting that it is stable and is a promising target for functional characterization and molecular breeding.…”

“…Notably, among all the QTLs identified, the QTL on chromosome 6, qRBSDV6‐1 , was detected through consideration of different subpopulations (Table 1). Additionally, this QTL overlapped with previously identified QTLs for RBSDVD resistance using different rice germplasms in other studies (Zheng et al ., 2012; Zhang et al ., 2016; Feng et al ., 2019, 2020; Xiao et al ., 2019), implying that it can be stably expressed in different genetic backgrounds and environmental conditions, and therefore has significant potential in rice breeding.…”

A Review of Vector-Borne Rice Viruses

“…For example, transgenic rice plants expressing artificial miRNA targeting RSV MP are highly resistant to the virus [ 190 ]. Recently, marker-free rice plants with stable and high resistance to RBSDV through RNA interference were also developed [ 191 ]. These marker-free transgenic lines driven by either maize ubiquitin-1 promoter or rice rbcS green tissue expression promoter in elite rice background should have great potential in breeding of resistant varieties to both RBSDV and SRBSDV.…”

RNAi‐based genetically engineered rice resistant to black‐streaked dwarf virus does not show adverse genetic effects: A multi‐omics analysis

“…Existing studies on the unanticipated effects of GE plants have focused on commercially planted or applied crop species, and almost no research has focused on the evaluation of the unintended effects in plants that are still in the process of biosafety evaluation. The research group of Shimin Zuo located at Yangzhou University used the S6 fragment of black-streaked dwarf virus (RBSDV) to construct an RNAi transformation vector to obtain RBSDV-resistant transgenic rice (Feng et al, 2021). These rice lines did produce the expected siRNA and showed very good results under field test conditions at different locations for several years (Feng et al, 2021).…”

“…The research group of Shimin Zuo located at Yangzhou University used the S6 fragment of black-streaked dwarf virus (RBSDV) to construct an RNAi transformation vector to obtain RBSDV-resistant transgenic rice (Feng et al, 2021). These rice lines did produce the expected siRNA and showed very good results under field test conditions at different locations for several years (Feng et al, 2021). As well as good resistance to RBSDV, it is important that the phenotypes and yields of these RNAi-based GE rice lines and traditionally bred rice lines are not different so that the lines resistance to RBSDV have potential for agricultural application (China patent: ZL201310202564.9).…”