水稻白条纹新基因st9(t)的初步定位

Mapping a novel rice white stripe gene,st9(t)

为了明确水稻白条纹自发突变体6001的表型特征和遗传特性,对突变体6001与野生型6028不同时期叶片中色素含量进行检测,同时,利用6001/9311 F2分离群体,对目的基因进行了微卫星(SSR)标记的初步定位。结果表明,2叶期时突变体6001叶绿素a、叶绿素b及胡萝卜素含量分别为野生型6028的12.4%、24.3%和14.7%,6叶期时分别为野生型6028的64.9%、65.3%和61.1%。对6001/6028、6001/9311 F2分离群体的调查分析表明,突变株与正常株分离比符合1∶3,突变性状呈隐性单基因遗传。以6001/9311 F2为定位群体,将突变基因定位于水稻第6染色体SSR标记RM136与RM19715之间,距离2个标记的遗传距离分别为0.8 cM和1.8 cM。由于该区段包含已报道的白条纹st1基因,因此以st1为目标片段设计特征引物,以突变体6001,野生型6028和9311的全基因组总DNA为模板扩增并测序,结果表明,该基因与st1不等位,为一个新基因,暂名为st9(t)。

To study the genetic and phenotypic characters of a rice white stripe mutant,6001,leaf pigment contents in mutant rice（6001） and wild type rice（6028） at different development stages were measured.A F2 population from 6001/ 9311,was used to locate the objective gene with rice SSR markers.The contents of chlorophyll a,chlorophyll b and carotenoid in 6001 at 2nd leaf stage was 12.4%,24.3% and 14.7% of those in 6028,respectively,and went up to 64.9%,65.3% and 61.1% of those in 6028 at 6th leaf stage,respectively.The segregation ratio of mutant（6001） to wild type（6028 or 9311） based on two F2 populations was 1∶3,indicating that the mutant trait was controlled by a recessive nucleus gene.The gene was mapped on rice chromosome 6 between SSR makers RM136 and RM19715 based on a F2 population from 6001/9311,and the genetic distances were 0.8 cM and 1.8 cM to the two markers,respectively.The region contains st1 gene which has been cloned,therefore a primer based on the st1 gene was designed afterwards,and the genome DNA of 6001,6028 and 9311 were amplified and sequenced.Result indicated that the gene is a new one non-allelic to st1 and related with rice stripe,which was named st9（t）.