水稻阶段性温敏白化转绿突变体stgra254的特征和基因定位

Characterization and Gene Mapping of Stage Thermo-sensitive Green-revertible Albino Mutant stgra254 in Rice

为了挖掘和鉴定更多的水稻白化转绿突变体用于基因功能的研究。从粳稻品种秀水09的EMS突变体库中发现了一个阶段性温敏白化转绿突变体stgra254,该突变体在28℃恒温条件下,第6片完全展开叶出现白斑,至分蘖盛期融合成片,最终叶片枯萎死亡;在32℃条件下,第6片叶白斑数目及白化程度明显弱于28℃,且3d后逐渐转绿;而24℃下的叶片表现正常。组织化学分析结果表明,白斑的形成和发展是一个程序性细胞死亡的过程,伴随着H_2O_2的积累。荧光仪分析显示,光系统Ⅱ的最大光能转化效率显著下降。遗传分析表明,该突变体叶色性状受1对隐性核基因控制。利用stgra254与珍汕97杂交得到F_2群体,借助集团分离分析法和SSR分子标记连锁分析,将其定位在4号染色体上的RM17206与RM17277标记之间,遗传距离分别为0.48,5.22cM。

In order to explore and identify more albino mutants for studying gene functions,a stage thermos-sensitive green-revertible albino mutant in rice,designated as stgra254,was isolated by treating the seeds of japonica variety Xiushui 09 using EMS.The phenotype of gra254 is thermos-sensitive.Under a constant temperature of 28℃,the white spots appeared on the fully expanded sixth leaves,and gradually enlarged and merged into one at maximum tillering stage.Then the leaves withered to death.The sixth leaf blades showed milder expression of the mutant phenotype under 32℃ condition than that under 28℃ condition,and gradually turned green from the third day onward.Under 24℃ condition,however,the gra254 plants produced normal green leaves.Histochemical staining analysis indicated that the albino trait of stgra254 was caused by the programmed cell death,which probably caused by oxidative burst accompanying by the accumulation of H2O2.Analysis by fluorescence analyzer presented that the maximal photochemical efficiency of PS Ⅱ decreased significantly.Genetic analysis indicated that the thermos-sensitive green-revertible albino trait was controlled by a single recessive nucleic gene.Based on the F2 population derived from a cross between stgra254 and Zhenshan 97,the stgra254 was located between the SSR markers of RM17206 and RM17277 on chromosome 4 by bulked segregant analysis and linkage analysis.The genetic distance was 0.48,5.22 cM, respectively.