Abstract: Root system not only plays an important supporting role to the shoot, but also is a main organ for plants to absorb water and nutrients. In order to study the role of BELL family factors in plant development, and response to environmental cues,  this study identified 4 BELL4 homologous genes in rice  through compassion with Arabidopsis. The elements of ABRE, GARE, ERE, ARE and DRE in their promoters were searched, which were possible responsive to stress and hormones. Real-time quantitative PCR analysis showed that the four BELL4 homologous genes were not only induced by drought, low temperature and salt stress, but also regulated by plant hormones, such as ethylene, gibberellin and abscisic acid, which indicating that these genes may respond to various hormones and stress in rice root. Further analysis with the phenotype of RNAi materials of OsBELL4A showed that inhibiting the expression of OsBELL4A could promote the expression level of WOX family genes, with inhibition of the primary root growth at the seedling stage of rice, but promote the number of crown roots. These results suggested that OsBELL4A might play an important regulatory role in rice root development and stress response.

Key words: OsBELL4A, hormone, stress, crown root, WOX gene family

摘要： 根系不仅对地上部分起着重要的支撑作用，也是植物吸收水分和养分的主要器官。为了研究BELL家族因子在植物生长发育及逆境胁迫应答中的功能，通过与拟南芥序列对比，鉴定到水稻4个BELL4同源基因，它们的启动子含有ABRE、GARE、ERE、ARE和DRE等应答逆境胁迫和激素信号的元件。在水稻根中进行实时定量PCR分析表明，这4个BELL4同源基因不仅受到干旱、低温以及盐等逆境胁迫诱导，而且还受到植物激素乙烯、赤霉素以及脱落酸的调控，表明这些基因可能应答多种激素及逆境胁迫。进一步分析OsBELL4A干扰材料表型发现，抑制OsBELL4A基因能够促进WOX家族基因的表达水平，并抑制水稻苗期初生根生长，但使冠根数量增多。这些结果表明水稻BELL4同源基因OsBELL4A在水稻根系发育及逆境胁迫应答中可能具有重要的调控功能。

关键词: OsBELL4A, 激素, 逆境胁迫, 冠根, WOX基因家族