Generation of transgenic papaya with double resistance to Papaya ringspot virus and Papaya leaf-distortion mosaic virus.
During the field tests of coat protein (CP)-transgenic papaya lines resistant to Papaya ringspot virus (PRSV), another Potyvirus sp., Papaya leaf-distortion mosaic virus (PLDMV), appeared as an emerging threat to the transgenic papaya. In this investigation, an untranslatable chimeric construct containing the truncated CP coding region of the PLDMV P-TW-WF isolate and the truncated CP coding region with the complete 3' untranslated region of PRSV YK isolate was transferred into papaya (Carica papaya cv. Thailand) via Agrobacterium-mediated transformation to generate transgenic plants with resistance to PLDMV and PRSV. Seventy-five transgenic lines were obtained and challenged with PRSV YK or PLDMV P-TW-WF by mechanical inoculation under greenhouse conditions. Thirty-eight transgenic lines showing no symptoms 1 month after inoculation were regarded as highly resistant lines. Southern and Northern analyses revealed that four weakly resistant lines have one or two inserts of the construct and accumulate detectable amounts of transgene transcript, whereas nine resistant lines contain two or three inserts without significant accumulation of transgene transcript. The results indicated that double virus resistance in transgenic lines resulted from double or more copies of the insert through the mechanism of RNA-mediated posttranscriptional gene silencing. Furthermore, three of nine resistant lines showed high levels of resistance to heterologous PRSV strains originating from Hawaii, Thailand, and Mexico. Our transgenic lines have great potential for controlling a number of PRSV strains and PLDMV in Taiwan and elsewhere.
Kung
Yi-Jung
YJ
Department of Plant Pathology, National Chung Hsing University, Taichung, Taiwan, R.O.C.
Bau
Huey-Jiunn
HJ
Wu
Yi-Ling
YL
Huang
Chiung-Huei
CH
Chen
Tsui-Miao
TM
Yeh
Shyi-Dong
SD
D015152:Blotting, Northern; D015139:Blotting, Southern; D036022:Capsid Proteins / Q000235:genetics*; D029441:Carica / Q000235:genetics / Q000276:immunology* / Q000821:virology; D024861:Genetic Enhancement; D005822:Genetic Vectors; D054884:Host-Pathogen Interactions; D007113:Immunity, Innate; D030821:Plants, Genetically Modified / Q000235:genetics / Q000276:immunology / Q000821:virology; D017800:Potyvirus / Q000502:physiology*; D012231:Rhizobium
D036022:Capsid Proteins; C073700:coat protein, Papaya ringspot virus