Location: Plant, Soil and Nutrition ResearchTitle: The cauliflower Orange gene enhances petiole elongation by suppressing expression of eukaryotic release factor 1) Author
Submitted to: New Phytologist
Publication Type: Peer reviewed journal
Publication Acceptance Date: 11/7/2010
Publication Date: 2/11/2011
Citation: Zhou, X., Lu, S., Ling, H., Li, L. 2011. The cauliflower Orange gene enhances petiole elongation by suppressing expression of eukaryotic release factor 1. New Phytologist. 190:89-100. Interpretive Summary: Carotenoids are indispensable to plants and play a critical role in human nutrition and health. The Or gene is of great interests because it has been demonstrated to confer high level accumulation of beta-carotene, the most potent provitamin A carotenoid, in plants. However, the Or gene appears to have pleiotropic effects on plant growth and development since the Or mutant exhibits other phenotypic changes such as enhanced cell elongation in petioles. In order to better use the Or gene to improve carotenoid content in food crops, fully understanding of OR function is essential. In this studies, we investigated the impact of the OR protein on plant growth and development via searching for its interacting proteins. We found that OR interacted with eukaryotic release factor 1-2. Like the Or mutant, the suppression of expression of the interacting protein caused an increased petiole elongation. Such a long petiole phenotype was found to be due to enhanced cell elongation. Our data collectively demonstrate that the cauliflower Or gene controls petiole cell elongation via suppressing the expression of eRF1 genes, and provides novel information for the molecular mechanisms involved in leaf petiole regulation.
Technical Abstract: The cauliflower Or gene affects plant growth and development in addition to conferring beta-carotene accumulation. This study was undertaken to investigate the molecular basis of the Or gene mutation in controlling plant growth. The OR protein was found to interact with cauliflower and Arabidopsis eukaryotic release factor 1-2 (eRF1-2), a member of eRF1 family, by yeast two-hybrid analysis. Concomitantly, the Or mutant showed a reduced expression of the BoeRF1 family genes. Transgenic cauliflower plants with suppressed expression of BoeRF1-2 and BoeRF1-3 were generated by RNA interference. Like the Or mutant, the BoeRF1 RNAi lines showed an increased elongation of leaf petiole. Such a long petiole phenotype was largely due to enhanced cell elongation, supported by longer cell length and elevated expression of genes involved in cell-wall loosening, such as pectin lyase1(PL1) and xyloglucan endotransglycosylase 8 (XET8). These findings demonstrate that the cauliflower Or gene controls petiole elongation via suppressing the expression of eRF1 genes, and provides new insights into the molecular mechanism of leaf petiole regulation.