Abstract: A G protein β-subunit gene in Rhizoctonia solani AG-1IA of rice which causes rice sheath blight disease was isolated. A 1958-bp PCR fragment was obtained by using the specific primers designed from the conserved region in G protein β-subunit homologues from Thanatephorus cucumeris. Amino acid sequence analysis showed that the sequence involved 366 deduced amino acid,encoded a putative peptide which shared significant identity (57.34%-88.14%) with G protein β-subunit homologues from other species. The full-length of the PCR fragment was 1.9 kb with a 1.7-kb open reading frame of the G protein β-subunit gene in R.solani AG-1IA. The results of RT-PCR showed that the G protein β-subunit gene transcript was greatly expressed in all growth period especially at the exponential phase,which indicated that the expression of the G protein β-subunit gene in R.solani AG-1IA might be regulated temporally and spatially.

Key words: rice, Rhizoctonia solani, G protein β-subunit gene, cloning, gene expression

摘要： 根据Thanatephorus cucumeris G蛋白β亚基序列（AY884129）设计引物，对水稻立枯丝核菌AG1IA的 G蛋白β亚基基因进行了克隆。PCR结果得到1条约为1.9 kb的扩增片段，包含1个约1.7 kb的完整开放阅读框，编码366个氨基酸。同源性检索发现该序列与大量Ｇ蛋白β亚基基因明显同源，一致性介于57.34%~88.14%。根据其推导cDNA序列设计引物进行RTPCR分析，发现该基因在对数生长期表达量最高，提示水稻立枯丝核菌AG1IA G蛋白β亚基基因可能具有时空表达特性。

关键词: 水稻, 立枯丝核菌, G蛋白β亚基基因