油菜素内酯（BR）超敏感嵌合受体的构建和水稻转基因表达

将油菜素内酯（brassinosteroids, BR）超敏感受体激酶基因 Sud1 与水稻抗病受体激酶基因 Xa21 经体外点突变后，构建了含 SUD1LRR-JM 结构域与 XA21 激酶域（kinase）的合成受体（chimera）基因 SNRG1。同时，构建了 SUD1LRR 突变体对照受体基因 SNRGmL 和 XA21 kinase 突变体对照受体基因 SNRGmK。通过基因枪（particle bombardment）转化技术，将 SNRG1、SNRGmL 和 SNRGmK 成功导入粳稻模式品种台北309的胚性愈伤组织中，并获得了再生植株和细胞株。经 PCR、Northern blot 分子检测和表型观察，证实外源基因已成功转入并整合到水稻基因组中。防卫基因表达结果表明，SNRG1 可能在体内微量 BR 的作用下激发了水稻的防卫反应。该结果为进一步研究 XA21 激酶的抗性激发机制奠定了基础。

A chimeric receptor kinase gene, SNRG1, was constructed by combining the Arabidopsis SUD1 (a brassinosteroid (BR) supersensitive receptor kinase) LRR-JM domain with the rice XA21 (a disease resistance receptor kinase) kinase domain, using in vitro point mutagenesis. Additionally, two control constructs were developed: the SUD1 LRR mutant (SNRGmL) and the XA21 kinase mutant (SNRGmK). Using particle bombardment, SNRG1, SNRGmL, and SNRGmK were successfully introduced into rice embryogenic calli of the japonica variety Taipei 309, resulting in the regeneration of transgenic rice plants and cell lines. The integration of the transgenic constructs was confirmed through PCR, Northern blot, and phenotypic analysis of the transformants. Preliminary results indicated that the rice defense pathways in SNRG1 transgenic plants may have been activated by trace amounts of endogenous BR. These findings lay the groundwork for further studies on the activation mechanism of the XA21 kinase upon BR ligand binding.