STUDIES ON GENETIC REGULATIONS OF RICE INTERNODES FORMATION AND ELONGATION

水稻茎秆是由一些伸长的内节组成的，为了更好地了解这些内节的遗传调控，伸长对水稻抗倒性育种和改良水稻品种的株形具有重要意义。然后，在这个项目中，我们试图检测和分离一些影响茎节间形成和伸长的矮化或相关基因。我们的研究结果如下：(1)筛选和检测了大量影响茎秆伸长和/或伸长节间分布格局的矮秆或相关突变体；(2)对一些突变体进行了表型鉴定，并利用一些分子标记(d50、ssi1、ssi2、d61和d11)将这些突变体基因定位在染色体上；(3)通过分子克隆成功地分离出了一些dwatf(d1、d6、d18、d61和gid1)或细长(Slr1)基因。(4)其中，d6被鉴定为noytted1型Homeobox基因家族成员OSH15(Oryza Sativa Homobox15)的功能缺失突变另一类是与植物激素赤霉素(d1、d18、gid1)或油菜素类固醇(D61)的生物合成或信号转导有关的基因功能缺失突变。

Rice culm is consisting of some elongated intemodes and to dear the genetic regulation of these intemodes elongation is important for breeding of lodging resistance and improvement of plant shape in rice cutivars. Then, in this project, we tried to detect and isolate some dwarf or related genes that affect culm internodes formation and elongation. Our research results are as follows :( 1 ) We screened and detected so many dwarf or related mutants affecting culm elongation and/or elongated internodes distribution patterns.( 2 ) We characterized phenotype of some mutants and mapped these mutant genes on the chromosome by useing some molecular markers (d50, Ssi1, ssi2, d61and d11).( 3 ) We succeeded to isolate some dwatf (d1, d6, d18, d61 and gid1) or slender (slr1) genes by molecular cloning.( 4 ) Among of them, d6 was identified as a loss-of-function mutation in OSH15(Oryza sativa homeobox15), a member of the knotted1-type homeobox gene family, and the others were as loss-of-function mutation in the genes related to biosynthesis or signal transduction of the plant hormones, gibberellin(d1, d18, gid1) or brassinosteroid (d61).Further studies on these genes function and interaction in the culm internodes formation and elongation ate in progress.