November
2010
, Volume
23
, Number
11
Pages
1,470
-
1,485
Authors
Lijun Sun,1,2
Haiying Ren,1,3
Ruoxue Liu,1
Baoyan Li,1
Tingquan Wu,1
Feng Sun,1
Huimin Liu,1
Xiaomeng Wang,1 and
Hansong Dong1
Affiliations
1Ministry of Agriculture of R. P. China Key Laboratory of Monitoring and Management of Crop Pathogens and Insect Pests, Nanjing Agricultural University, Nanjing, 210095, China; 2Nanjing Institute for Comprehensive Utilization of Wild Plants, Nanjing, 210042, China; and 3Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China
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Accepted 7 July 2010.
Abstract
Various thioredoxin (Trx) proteins have been identified in plants. However, many of the physiological roles played by these proteins remain to be elucidated. We cloned a TRXh-like gene predicted to encode an h-type Trx in tobacco (Nicotiana tabacum) and designated it NtTRXh3, based on the biochemical activity of the NtTRXh3 protein. Overexpression of NtTRXh3 conferred resistance to Tobacco mosaic virus and Cucumber mosaic virus, both of which showed reduced multiplication and pathogenicity in NtTRXh3-overexpressing plants compared with controls. NtTRXh3 overexpression also enhanced tobacco resistance to oxidative stress induced by paraquat, an herbicide that inhibits the production of reducing equivalents by chloroplasts. The NtTRXh3 protein localized exclusively to chloroplasts in coordination with the maintenance of cellular reducing conditions, which accompanied an elevation in the glutathione/glutathione disulfide couple ratio. NtTRXh3 gene expression and NtTRXh3 protein production were necessary for these defensive responses, because they were all arrested when NtTRXh3 was silenced and the production of NtTRXh3 protein was abrogated. These results suggest that NtTRXh3 is involved in the resistance of tobacco to virus infection and abiotic oxidative stress.
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© 2010 The American Phytopathological Society