Nucleotide sequence-homology-independent breakdown of transgenic resistance by more virulent virus strains and a potential solution.
Controlling plant viruses by genetic engineering, including the globally important Papaya ringspot virus (PRSV), mainly involves coat protein (CP) gene mediated resistance via post-transcriptional gene silencing (PTGS). However, the breakdown of single- or double-virus resistance in CP-gene-transgenic papaya by more virulent PRSV strains has been noted in repeated field trials. Recombination analysis revealed that the gene silencing suppressor HC-Pro or CP of the virulent PRSV strain 5-19 is responsible for overcoming CP-transgenic resistance in a sequence-homology-independent manner. Transient expression assays using agro-infiltration in Nicotiana benthamiana plants indicated that 5-19 HC-Pro exhibits stronger PTGS suppression than the transgene donor strain. To disarm the suppressor from the virulent strain, transgenic papaya lines were generated carrying untranslatable 5-19 HC-Pro, which conferred complete resistance to 5-19 and other geographic PRSV strains. Our study suggested the potential risk of the emergence of more virulent virus strains, spurred by the deployment of CP-gene-transgenic crops, and provides a strategy to combat such strains.
1] Department of Plant Pathology, National Chung Hsing University, Taichung, Taiwan, R.O.C. [2] NCHU-UCD Plant and Food Biotechnology Center, National Chung Hsing University, Taiwan, R.O.C.
Yi-Jung
YJ
Kung
1] Department of Plant Pathology, National Chung Hsing University, Taichung, Taiwan, R.O.C. [2] Department of Chinese Pharmaceutical Sciences and Chinese Medicine Resources, China Medical University, Taichung, Taiwan, R.O.C.
Bang-Jau
BJ
You
1] Department of Plant Pathology, National Chung Hsing University, Taichung, Taiwan, R.O.C. [2] NCHU-UCD Plant and Food Biotechnology Center, National Chung Hsing University, Taiwan, R.O.C.
Joseph A J
JA
Raja
Department of Plant Pathology, National Chung Hsing University, Taichung, Taiwan, R.O.C.
Kuan-Chun
KC
Chen
Department of Plant Pathology, National Chung Hsing University, Taichung, Taiwan, R.O.C.
Chiung-Huei
CH
Huang
Department of Plant Pathology, National Chung Hsing University, Taichung, Taiwan, R.O.C.
Huey-Jiunn
HJ
Bau
1] Department of Plant Pathology, National Chung Hsing University, Taichung, Taiwan, R.O.C. [2] Agricultural Biotechnology Center, National Chung Hsing University, Taichung, Taiwan, R.O.C.
Ching-Fu
CF
Yang
Department of Plant Pathology, National Chung Hsing University, Taichung, Taiwan, R.O.C.
Chung-Hao
CH
Huang
Department of Plant Pathology, National Chung Hsing University, Taichung, Taiwan, R.O.C.
Chung-Ping
CP
Chang
1] Department of Plant Pathology, National Chung Hsing University, Taichung, Taiwan, R.O.C. [2] NCHU-UCD Plant and Food Biotechnology Center, National Chung Hsing University, Taiwan, R.O.C. [3] Department of Chinese Pharmaceutical Sciences and Chinese Medicine Resources, China Medical University, Taichung, Taiwan, R.O.C.
Shyi-Dong
SD
Yeh
D036022:Capsid Proteins / Q000235:genetics; D029441:Carica / Q000235:genetics* / Q000821:virology*; D010935:Plant Diseases / Q000235:genetics / Q000517:prevention & control / Q000821:virology; D010942:Plant Viruses / Q000472:pathogenicity*; D030821:Plants, Genetically Modified / Q000235:genetics / Q000821:virology*; D012689:Sequence Homology, Nucleic Acid; D019076:Transgenes / Q000235:genetics*; D014774:Virulence / Q000235:genetics*
D036022:Capsid Proteins