title: RNA-interference in rice against Rice tungro bacilliform virus results in its decreased accumulation in inoculated rice plants.
abstract: Rice tungro is a viral disease seriously affecting rice production in South and Southeast Asia. Tungro is caused by the simultaneous infection in rice of Rice tungro bacilliform virus (RTBV), a double-stranded DNA virus and Rice tungro spherical virus (RTSV), a single-stranded RNA virus. To apply the concept of RNA-interference (RNAi) for the control of RTBV infection, transgenic rice plants expressing DNA encoding ORF IV of RTBV, both in sense as well as in anti-sense orientation, resulting in the formation of double-stranded (ds) RNA, were raised. RNA blot analysis of two representative lines indicated specific degradation of the transgene transcripts and the accumulation of small molecular weight RNA, a hallmark for RNA-interference. In the two transgenic lines expressing ds-RNA, different resistance responses were observed against RTBV. In one of the above lines (RTBV-O-Ds1), there was an initial rapid buildup of RTBV levels following inoculation, comparable to that of untransformed controls, followed by a sharp reduction, resulting in approximately 50-fold lower viral titers, whereas the untransformed controls maintained high levels of the virus till 40 days post-inoculation (dpi). In RTBV-O-Ds2, RTBV DNA levels gradually rose from an initial low to almost 60% levels of the control by 40 dpi. Line RTBV-O-Ds1 showed symptoms of tungro similar to the untransformed control lines, whereas line RTBV-O-Ds2 showed extremely mild symptoms.
authors.affiliation: Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi, 110021, India.
authors.forename: Himani
authors.initials: H
authors.lastname: Tyagi
authors.forename: Shanmugam
authors.initials: S
authors.lastname: Rajasubramaniam
authors.forename: Manchikatla Venkat
authors.initials: MV
authors.lastname: Rajam
authors.forename: Indranil
authors.initials: I
authors.lastname: Dasgupta
mesh_terms: D017343:Genes, Plant; D008970:Molecular Weight; D012275:Oryza / Q000235:genetics* / Q000821:virology; D030821:Plants, Genetically Modified / Q000235:genetics* / Q000821:virology; D034622:RNA Interference; D018749:RNA, Plant / Q000378:metabolism; D052641:Tungrovirus / Q000302:isolation & purification / Q000472:pathogenicity*
chemical_list: D018749:RNA, Plant