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利用mRNA差异显示技术(DDRT-PCR),从非亲和性稻瘟菌生理小种131侵染的水稻品种爱知旭(Oryza smti-va L.cv Aichi-asahi)叶片中分离了8个诱导差异表达的cDNA片段。对这8个差示片段进行了回收、重扩增和克隆,以其中一个长度为321碱基并与甘露糖结合水稻凝集素和水稻盐诱导蛋白基因高度同源的差示片段为探针,筛选水稻非亲和性cDNA文库,获得12个阳性克隆。序列测定和数据库查询表明该基因的cDNA与水稻凝集素基因的cDNA及盐诱导蛋白基因的cDNA核苷酸同源性高达96％,推定的氨基酸序列与甘露糖结合水稻凝集素的氨基酸序列一致,与水稻盐诱导蛋白仅相差2个氨基酸。Southem杂交显示该基因在水稻基因组中有两个同源拷贝数,North杂交表明非亲和性稻瘟菌侵染可强烈诱导该基因表达。因此推测该基因参与了水稻对稻瘟菌侵染的防御反应。
Eight Inducers were isolated from the leaves of Oryza smti-va L.cv Aichi-asahi infected with non-inoculum-resistant Magnaporthern ruminalis 131 using mRNA differential display (DDRT-PCR) Differentially expressed cDNA fragments. The eight fragments were recovered, re-amplified and cloned. One of them was 321 bp in length and was detected by a differential fragment with high homology to mannose-binding rice lectin and rice salt-inducible protein gene. Screening of rice non-affinity cDNA library, 12 positive clones were obtained. Sequence analysis and database search showed that the cDNA homology between cDNA of this gene and rice lectin gene and salt-induced protein gene was as high as 96%. The putative amino acid sequence was consistent with the amino acid sequence of mannose-binding rice lectin, Only two amino acids differ from rice salt-inducible protein. Southem hybridization showed that the gene has two homologous copies in the rice genome. North hybridization indicates that non-inducible Magnaporthe griseus infection can strongly induce the gene expression. Therefore, we speculated that the gene involved in rice defense against Magnaporthe grisea.