Interactions of the mannose-binding rice lectin with sugar chains of ConA-binding glycoproteins secreted by rice blast fungus

甘露糖结合水稻凝集素与稻瘟菌分泌的刀豆蛋白 A 结合糖蛋白糖链的相互作用

基本信息

批准号：
12460021
负责人：
TERAOKA Tohru
金额：
$ 10.3万
依托单位：
Tokyo University of Agriculture and Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

项目摘要

The mannose-binding rice lectin (MRL) is induced by some stresses of drought, disease and wound. MRL has a potential activity to agglutinate spores and protoplasts of Magnaporthe girisea and also intact cells of Xanthomonas oryzae, and also accumulated around the infection sites. MRL is composed of some isolectins ; 2 major ones have pi 4.85 and 4.74, the minor pi 4.66, 4.56, and 4.44, whereas all ones have about MW 15,000 as a single peptide. We have already isolated and identified the major one corresponding to pI4.85, named MRL4.85. Analysis of the MRL4.85 gene and the genome structures suggested that (1) MRL4.85 is almost identical to salt and drought stress-inducible salT gene products in rice plant, (2) MRL4 85 gene is transcribed to at least 5 mRNAs by alternative splicing ; one lacks 8 amino acid residues without flame | shift and the other differ in the length of 3'-UTR, (3) the 5'-UTR regulating the transcripts of MRL4.85 differs in length and lack the part of sequence contai … More ned in one of the salT gene. Further, screening of BAG library and the data of the rice genome project suggested that MRL4.85 gene is located at the first chromosome in rice plant and the similar sequence corresponding to an isolectin exists at about 130kb upstream of MRL4.85.To verify our hypotheses that MRL may function as plant antibodies or receptors in host-parasite interaction, we have tried to obtain the transformants of rice plant to express excessively or suppressively the MRL4.85 product, using the binary vector pC1304E with CaMV 35S promoter in which the positive or negative strands are integrated. And some ten transformants are obtained at callus level.Con A-binding glycoproteinis secreted from germinating conidia of M. grisea, which potentially interact with MRL and have activity to promote appressorium formation and growth of infection hyphae in planta, are purified by Con A affinity chromatography and HPLC. The major glycoprotein is MW 28k and modified by sugar chains at many AA residues, provably not by N-glycosylation but by O-glycosylation. Less

甘露糖结合的水稻凝集素（MRL）是由干旱、疾病和伤口等胁迫诱导的，MRL具有凝集稻瘟病菌孢子和原生质体以及米黄单胞菌完整细胞的潜在活性，并且也在感染部位周围积累。 MRL 由一些同工凝集素组成；两种主要的 pi 为 4.85 和 4.74，次要的 pi 为 4.66， 4.56 和 4.44，而所有肽的分子量均约为 15,000，我们已经分离并鉴定了对应于 pI4.85 的主要肽，命名为 MRL4.85 对 MRL4.85 基因和基因组结构的分析表明： (1) MRL4.85与水稻中盐和干旱胁迫诱导的salT基因产物几乎相同，(2) MRL4 85基因被转录通过选择性剪接至少 5 个 mRNA；其中一个缺少 8 个氨基酸残基，而另一个的 3'-UTR 长度不同，(3) 调节 MRL4.85 转录本的 5'-UTR 长度不同并且缺少salT基因中包含的部分序列。进一步，BAG文库的筛选和水稻基因组计划的数据表明，MRL4.85基因位于第一个染色体上。水稻植物和对应于异凝集素的相似序列存在于MRL4.85上游约130kb处。为了验证我们的抗体MRL可以在宿主-寄生虫相互作用中充当植物或受体，我们尝试获得水稻植物的转化体来表达使用具有CaMV 35S启动子的双元载体pC1304E（其中整合有正链或负链），过度或抑制MRL4.85产物，并产生约十个转化体。 Con A 结合糖蛋白是由稻瘟病菌发芽分生孢子分泌的，它可能与 MRL 相互作用，并具有促进植物中附着胞形成和感染菌丝生长的活性，通过 Con A 亲和层析和 HPLC Major 进行纯化。糖蛋白的分子量为 28k，并在许多 AA 残基上被糖链修饰，可能不是通过 N-糖基化，而是通过 O-糖基化。