Genetic and biochemical analyzes of an accelerated internode overgrowth mutant in rice.

以水稻品种Koshi-Hikari为材料，用伽马射线种子诱变获得了水稻节间超长突变体Au-odori(AO)。由日本赤霉菌引起的Bakanae病引起的苗期苗条表型相似，表现为一个隐性基因ao-1(加速节间过度生长1)。突变苗对赤霉素A_3及其延缓剂配施反应的检测结果。用AO(ao-1)×Kotaka-Tamanishiki(d-18)和AO(ao-1)×Tangin-bozu(d-35)两个杂交组合进行的双突变分析也支持这一观点。对地上部糖组分的分析结果表明，与Koshi-hikar相比，突变体的半纤维素I和纤维素组分的含糖量显著增加。对AO幼苗地上部的可溶性蛋白和细胞壁蛋白进行了双向分析利用Blastn E-mail Server(NCBI)和DNASIS-MAC(Hitachi Software Engineering Co.)的DNA数据库对从油菜伸长节间提取的mRNADNA文库中的205个测序克隆进行同源性分析。有限公司)。结果表明，其中41个克隆与数据库中记录的DNA序列有部分同源性(氨基酸水平为40%)，进一步克隆ao-1基因的实验正在进行中。

A rice internode overgrowth mutant, awa-odori (AO) was induced from a japonica cultivar, Koshi-hikari by gamma-ray seed irradiation. The slender shoot phenotype alike in seedlings infected by "bakanae" disease caused by Gibberella fujikuroi has been expressed by a recessive gene named ao-1(accelerated internode overgrowth 1). The results of examination on responsibility of mutant seedlings to some combined applications of GA_3 and its retardant, Uniconazole suggested that this characteristics of the mutant is not caused by an over product of endogenous gibberellins as shown in "bakanae" disease.Double mutant analysis with two cross combinations of AO (ao-1) x Kotake-tamanishiki (d-18) and AO (ao-1) x Tangin-bozu(d-35) also supported this suggestion.The result of analysis on sugar components of shoot showed that sugar contents of hemicellulose I and cellulose fractions increased significantly in the mutant compared with Koshi-hikari.Two-dimensional analysis of soluble and cell wall proteins extracted from the basal area of seedling shoot of AO mutant and Koshi-hikari was carried out and some specific protein spots in the mutant were detected from both 2D-PAGEs.205 sequenced clones in the cDNA library isolated from mRNAs extracted from elongating internodes of AO shoot were researched on the homology to the other nuclertide sequences using DNA-database of Blastn E-mail Server (NCBI) and DNASIS-MAC (Hitachi Software Engineering Co., Ltd.). The result showed that 41 clones among them encoded a partial homology (>40% in the amino acid sequence level) to DNA sequences recorded in the databases.Further experiment for cloning ao-1 gene is now being continued.