Naito Takahito, Yamashino Takafumi, Kiba Takatoshi, Koizumi Nobuya, Kojima Mikiko, Sakakibara Hitoshi, Mizuno Takeshi
Laboratory of Molecular Microbiology, School of Agriculture, Nagoya University, Nagoya, Japan.
Biosci Biotechnol Biochem. 2007 May;71(5):1269-78. doi: 10.1271/bbb.60681. Epub 2007 May 7.
In Arabidopsis thaliana, each member of a large family of AS2/LOB (ASYMMETRIC LEAVES 2/LATERAL ORGAN BOUNDARIES) genes encodes a plant specific protein. They are highly homologous to one other. A mutational lesion in the representative AS2 gene results in the development of anomalous asymmetric leaves, implying that these family members commonly play some roles in plant development. In this study, we found that ectopic overexpression of ASL9 (ASYMMETRIC LEAVES 2 LIKE 9) in transgenic plants displayed a markedly anomalous architecture during the development of adult plants. Then we found that among AS2/LOB family members, ASL9 is distinct from the others in that it is exclusively regulated by the plant hormone cytokinin in a manner dependent on His-Asp phosphorelay signal transduction. We further found that when supplied externally in a medium, cytokinin specifically affected the growth properties of ASL9-ox seedlings. Taken together, the results of this study suggest that the cytokinin-induced ASL9 gene is implicated in regulation of the development of Arabidopsis thaliana.
在拟南芥中，AS2/LOB（不对称叶片2/侧生器官边界）基因大家族的每个成员都编码一种植物特有的蛋白质。它们彼此高度同源。代表性的AS2基因中的一个突变损伤会导致异常不对称叶片的发育，这意味着这些家族成员通常在植物发育中发挥某些作用。在本研究中，我们发现转基因植物中ASL9（类不对称叶片2 9）的异位过表达在成年植物发育过程中表现出明显异常的结构。然后我们发现，在AS2/LOB家族成员中，ASL9与其他成员不同，因为它仅由植物激素细胞分裂素以依赖于组氨酸-天冬氨酸磷酸化信号转导的方式调控。我们进一步发现，当在培养基中外部提供时，细胞分裂素特异性地影响ASL9过表达幼苗的生长特性。综上所述，本研究结果表明，细胞分裂素诱导的ASL9基因参与了拟南芥发育的调控。
