摘要
To investigate whether ethylene is involved in tomato plants in response to the invasion of viroid, tomato cv. Pearson and its ethylene-insensitive mutant Never ripe （Nr） was challenged with Tomato chlorotic dwarf viroid （TCDVd）. Both Pearson and Nr plants developed various symptoms including dwarf, bunch, reduced leaf size, leaf chlorosis, and necrosis at 3-wk-post-inoculation and thereafter even though the stunting in Nr was not as severe as in Pearson plants. The sizes of fruits were also significantly reduced in the viroid-infected plants. Treatments of Pearson with ethephon, an ethylene-releasing compound, mimicked TCDVd in induction of stunting and pathogenesis-related （PR） genes in the plants. Pretreatment of Pearson plants prior to TCDVd-inoculation or ethephon application with silver thiosulfate （STS）, an ethylene action inhibitor, partially suppressed the viroid- or ethephon-induced symptoms as well as PR gene expression. In addition, Nr and STS-treated Pearson exhibited a slightly lower viroid titre in comparison to the control Pearson plants. These results suggest that ethylene is involved but plays a limited role in TCDVd-induced symptom development.
To investigate whether ethylene is involved in tomato plants in response to the invasion of viroid, tomato cv. Pearson and its ethylene-insensitive mutant Never ripe （Nr） was challenged with Tomato chlorotic dwarf viroid （TCDVd）. Both Pearson and Nr plants developed various symptoms including dwarf, bunch, reduced leaf size, leaf chlorosis, and necrosis at 3-wk-post-inoculation and thereafter even though the stunting in Nr was not as severe as in Pearson plants. The sizes of fruits were also significantly reduced in the viroid-infected plants. Treatments of Pearson with ethephon, an ethylene-releasing compound, mimicked TCDVd in induction of stunting and pathogenesis-related （PR） genes in the plants. Pretreatment of Pearson plants prior to TCDVd-inoculation or ethephon application with silver thiosulfate （STS）, an ethylene action inhibitor, partially suppressed the viroid- or ethephon-induced symptoms as well as PR gene expression. In addition, Nr and STS-treated Pearson exhibited a slightly lower viroid titre in comparison to the control Pearson plants. These results suggest that ethylene is involved but plays a limited role in TCDVd-induced symptom development.
基金
Teresa Molen (MSc) fortechnical support, Dr. Nie Bihua for data analysis, andthe greenhouse staff of the Potato Research Centre of Agriculture and Agri-Food Canada for maintenance ofthe plant materials
The research was supported by Agriculture and Agri-Food of Canada under the Peer-Reviewed Project #50 to Dr. Nie Xianzhou
