Open AccessAn h-Type Thioredoxin Functions in Tobacco Defense Responses to Two Species of Viruses and an Abiotic Oxidative Stress
Author(s) -
Lijun Sun,
Haiyan Ren,
Ruoxue Liu,
Baoyan Li,
Tianbin Wu,
Feng Sun,
Huimin Liu,
Xiaomeng Wang,
Hansong Dong
Publication year - 2010
Publication title -
molecular plant-microbe interactions
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.565
H-Index - 153
eISSN - 1943-7706
pISSN - 0894-0282
DOI - 10.1094/mpmi-01-10-0029
Subject(s) - tobacco mosaic virus , thioredoxin , biology , nicotiana tabacum , cucumber mosaic virus , oxidative stress , glutathione , chloroplast , abiotic stress , paraquat , gene , nicotiana benthamiana , microbiology and biotechnology , peroxiredoxin , virus , biochemistry , plant virus , virology , enzyme , peroxidase
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.