AN INTRON SEQUENCE IS PRESENT IN THE 3′ UTR OF TOMATO Cf9 GENE

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.