title: Enhanced virus resistance in transgenic maize expressing a dsRNA-specific endoribonuclease gene from E. coli.
abstract: Maize rough dwarf disease (MRDD), caused by several Fijiviruses in the family Reoviridae, is a global disease that is responsible for substantial yield losses in maize. Although some maize germplasm have low levels of polygenic resistance to MRDD, highly resistant cultivated varieties are not available for agronomic field production in China. In this work, we have generated transgenic maize lines that constitutively express rnc70, a mutant E. coli dsRNA-specific endoribonuclease gene. Transgenic lines were propagated and screened under field conditions for 12 generations. During three years of evaluations, two transgenic lines and their progeny were challenged with Rice black-streaked dwarf virus (RBSDV), the causal agent of MRDD in China, and these plants exhibited reduced levels of disease severity. In two normal years of MRDD abundance, both lines were more resistant than non-transgenic plants. Even in the most serious MRDD year, six out of seven progeny from one line were resistant, whereas non-transgenic plants were highly susceptible. Molecular approaches in the T12 generation revealed that the rnc70 transgene was integrated and expressed stably in transgenic lines. Under artificial conditions permitting heavy virus inoculation, the T12 progeny of two highly resistant lines had a reduced incidence of MRDD and accumulation of RBSDV in infected plants. In addition, we confirmed that the RNC70 protein could bind directly to RBSDV dsRNA in vitro. Overall, our data show that RNC70-mediated resistance in transgenic maize can provide efficient protection against dsRNA virus infection.
authors.affiliation: State Key Laboratory of Agro-Biotechnology and MOA Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, P. R. China.
authors.forename: Xiuling
authors.initials: X
authors.lastname: Cao
authors.forename: Yingui
authors.initials: Y
authors.lastname: Lu
authors.forename: Dianping
authors.initials: D
authors.lastname: Di
authors.forename: Zhiyan
authors.initials: Z
authors.lastname: Zhang
authors.forename: He
authors.initials: H
authors.lastname: Liu
authors.forename: Lanzhi
authors.initials: L
authors.lastname: Tian
authors.forename: Aihong
authors.initials: A
authors.lastname: Zhang
authors.forename: Yanjing
authors.initials: Y
authors.lastname: Zhang
authors.forename: Lindan
authors.initials: L
authors.lastname: Shi
authors.forename: Bihong
authors.initials: B
authors.lastname: Guo
authors.forename: Jin
authors.initials: J
authors.lastname: Xu
authors.forename: Xifei
authors.initials: X
authors.lastname: Duan
authors.forename: Xianbing
authors.initials: X
authors.lastname: Wang
authors.forename: Chenggui
authors.initials: C
authors.lastname: Han
authors.forename: Hongqin
authors.initials: H
authors.lastname: Miao
authors.forename: Jialin
authors.initials: J
authors.lastname: Yu
authors.forename: Dawei
authors.initials: D
authors.lastname: Li
mesh_terms: D004722:Endoribonucleases / Q000235:genetics* / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism; D023061:Gene Order; D016679:Genome, Viral; D010641:Phenotype; D010935:Plant Diseases / Q000235:genetics* / Q000276:immunology* / Q000821:virology; D030821:Plants, Genetically Modified; D011485:Protein Binding; D012330:RNA, Double-Stranded / Q000378:metabolism*; D003313:Zea mays / Q000235:genetics* / Q000821:virology*
chemical_list: D029968:Escherichia coli Proteins; D012330:RNA, Double-Stranded; D004722:Endoribonucleases