The Interactions among DWARF10, Auxin and Cytokinin Underlie Lateral Bud Outgrowth in Rice

• Published in: Journal of integrative plant biology Vol. 52; no. 7; pp. 626 - 638
• Main Authors: Zhang, Shuying, Li, Gang, Fang, Jun, Chen, Weiqi, Jiang, Haipai, Zou, Junhuang, Liu, Xue, Zhao, Xianfeng, Li, Xiaobing, Chu, Chengcai, Xie, Qi, Jiang, Xiangning, Zhu, Lihuang
• Format: Journal Article
• Language: English
• Published: Melbourne, Australia Melbourne, Australia : Blackwell Publishing Asia 01-07-2010; Blackwell Publishing Asia; The State Key Laboratory of Plant Genomics and National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; Graduate University of Chinese Academy of Sciences, Beijing 100049, China%The State Key Laboratory of Plant Genomics and National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China%College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, China%College of Agronomy, Shenyang Agricultural University, Shenyang 110161, China%Department of Ophthalmology, University of Utah, Salt Lake City, UT 84132, USA
• Subjects: Cytokinins - metabolism; Gene Expression Regulation, Plant - genetics; Gene Expression Regulation, Plant - physiology; Indoleacetic Acids - metabolism; Oryza - genetics; Oryza - growth & development; Oryza - metabolism; Plant Proteins - genetics; Plant Proteins - metabolism; Plant Shoots - genetics; Plant Shoots - growth & development; Plant Shoots - metabolism; Plants, Genetically Modified - genetics; Plants, Genetically Modified - growth & development; Plants, Genetically Modified - metabolism; Reverse Transcriptase Polymerase Chain Reaction; RNA干扰; Tandem Mass Spectrometry; 外源生长素; 相互作用; 细胞分裂素; 细胞生长; 转基因植物
• ISSN: 1672-9072; 1744-7909
• DOI: 10.1111/j.1744-7909.2010.00960.x

Previous studies have shown that DWARFIO （D10） is a rice ortholog of MAX41RMS1/DAD1, encoding a carotenoid cleavage dioxygenase and functioning in strigolactones/strigolactone-derivatives （SL） biosynthesis. Here we use DIO. RNA interference （RNAi） transgenic plants similar to dlO mutant in phenotypes to investigate the interactions among DIO, auxin and cytokinin in regulating rice shoot branching. Auxin levels in node 1 of both decapitated DIO.RNAi and wild type plants decreased significantly, showing that decapitation does reduce endogenous auxin concentration, but decapitation has no clear effects on auxin levels in node 2 of the same plants. This implies that node 1 may be the location where a possible interaction between auxin and DIO gene would be detected. DIO expression in node 1 is inhibited by decapitation, and this inhibition can be restored by exogenous auxin application, indicating that DIO may play an important role in auxin regulation of SL. The decreased expression of most OsPINs in shoot nodes of DIO-RNAi plants may cause a reduced auxin transport capacity. Furthermore, effects of auxin treatment of decapitated plants on the expression of cytokinin biosynthetic genes suggest that DIO promotes cytokinin biosynthesis by reducing auxin levels. Besides, in DIO-RNAi plants, decreased storage cytokinin levels in the shoot node may partly account for the increased active cytokinin contents, resulting in more tillering phenotypes.