MADS1, a novel MADS-box protein, is involved in the response of Nicotiana benthamiana to bacterial harpinXoo

• Published in: Journal of experimental botany Vol. 67; no. 1; pp. 131 - 141
• Main Authors: Zhang, Huajian, Teng, Wenjun, Liang, Jingang, Liu, Xinyu, Zhang, Haifeng, Zhang, Zhengguang, Zheng, Xiaobo
• Format: Journal Article
• Language: English
• Published: Oxford University Press 01.01.2016
• Subjects: RESEARCH PAPER
• ISSN: 0022-0957; 1460-2431

MADS-box transcription factor genes are well known for their role in floral organ and seed development. In this study, a novel MADS-box-containing gene, designated NbMADS1, was isolated from leaves of Nicotiana benthamiana. The full-length cDNA was 666bp and encoded a putative polypeptide of 221 aa with a mass of 24.3kDa. To assess the role of NbMADS1 in the defence response to bacterial harpinXoo, an elicitor of the hypersensitive response, a loss-of-function experiment was performed in N. benthamiana plants using virus-induced gene silencing. Analyses of electrolyte leakage revealed more extensive cell death in the control plants than in NbMADS1-silenced plants. The NbMADS1-silenced plants showed impaired harpinXoo-induced stomatal closure, decreased harpinXoo-induced production of hydrogen peroxide (H₂O₂) and nitric oxide (NO) in guard cells, and reduced harpinXoo-induced resistance to Phytophthora nicotianae. The compromised stomatal closure observed in the NbMADS1-silenced plants was inhibited by the application of H₂O₂ and sodium nitroprusside (an NO donor). Taken together, these results demonstrate that the NbMADS1–H₂O₂–NO pathway mediates multiple harpinXoo-triggered responses, including stomatal closure, hypersensitive cell death, and defence-related gene expression, suggesting that NbMADS1 plays an important role in regulating the response to harpinXoo in N. benthamiana plants.