摘要
从番茄（ＬｙｃｏｐｅｒｓｉｃｏｎｅｓｃｕｌｅｎｔｕｍＭｉｌ．）抗病品种“中杂９号”基因组ＤＮＡ中扩增并克隆了番茄抗叶霉病基因Ｃｆ９。序列分析结果表明，该基因全长２７５１ｂｐ，含有一个编码８６３个氨基酸的开放阅读框架。在该基因的３′ＵＴＲ区发现了一段未曾报道的内含子序列，长１１５ｂｐ，它所处的位置与番茄另一个抗叶霉病基因Ｃｆ２内含子的位置相似，其５′和３′边界序列为一重复序列，ＴＣＣＡＧＧ（Ｔ）ＡＴＴＣ，并与Ｃｆ２基因内含子边界序列高度同源。与已报道的Ｃｆ９的ｃＤＮＡ序列相比，它的第３７１位的核苷酸Ｔ突变成了Ｃ，从而使其编码蛋白的ＬＲＲ区第１２１位的亮氨酸突变为脯氨酸。
Tomato leaf mould resistance gene Cf9 was amplified by PCR and cloned from the genomic DNA of a tomato (Lycopersicon esculentum Mill.) cultivar (“Zhongza 9”). Sequence analysis indicates that this Cf9 gene is 2 751 bp long and contains an open reading frame encoding a protein of 863 amino acids. An intron of 115 bp in length is found in the 3′ untranslated region of this gene. The exon/intron borders are replicate sequences, TCCAGG(T)ATTC, which shares high homology with those of the two genes of Cf2 which is another leaf mould resistant gene locus in tomato. Compared with the previously reported cDNA sequence of Cf9, a single change of T to C occurs at the nucleotide position of 371 in this PCR amplified Cf9 gene, which converts Leu 121 to Pro in the LRR region of the encoded protein.
