水稻白化突变体alb21生理特性和基因定位

高等植物叶绿体的正常发育需要叶绿体基因和核基因相互协调，这些基因的突变将导致叶绿体发育的缺陷．通过同位素诱变，获得了1例水稻的白化突变体alb21，其在幼苗时期就表现出白化性状，生长1个月左右逐渐死亡．遗传学分析表明，该突变属于单基因隐性突变；电镜观察表明，突变体细胞内完全丧失了叶绿体结构，只有一些空泡状的结构．突变体中既没有检测出叶绿素a或b，也没有检测出叶绿素合成的前体——原脱植基叶绿素a，说明此突变体的叶绿素合成途径受阻．因此，推测Alb21基因的突变，导致叶绿体发育受阻，叶绿素a或b以及叶绿素合成的前体——原脱植基叶绿素a不能合成．利用本实验室开发的水稻InDel分子标记，将该突变基因定位在第3条染色体上分子标记R3M51—2与R3M52—5之间约1520kb范围内．这些结果为该基因的克隆及叶绿体发育过程中的功能研究奠定了基础．

The physiological character and molecular mapping in rice albino21 mutant

In higher plants, the chloroplast development requires coordinated expression of genes from the nuclear and plastid genomes. The mutations of these genes would lead to the defective of chloroplast development. An albino rice mutant was isolated using isotope mutagenesis strategy. Genetics analysis indicated that this phenotype was controlled by a single recessive gene called alb21. Electron microscopic examination showed that the mutant plastids contained some empty vesicles without thyla-koids. In addition, our analysis showed that the mutants had no neither chlorophyll a and chlorophyll b, nor monovinyl protochlo-rophyllide a ,chlorophyll precursor, was detected in the' mutant leaves. Alb21 was mapped to a region of about 1520 kb delimited by molecular markers R3M51 -2 and R3M52 -5 on chromosome 3. The molecular cloning and functional analysis of this gene will be further undertaken.