以籼稻93-11为背景的水稻突变体中发现一个黄绿叶突变体(yellow-green leaf,ygl10)。形态分析表明,与野生型93-11相比,ygl10突变体株高、穗长降低,结实率下降。叶绿素含量测定表明,ygl10突变体中叶绿素a、叶绿素b和类胡萝卜素含量均极显著降低,其中叶绿素b降幅最大,只有野生型的2%。叶绿体超微结构观察表明,突变体中类囊体和基粒片层数量明显减少。遗传分析结果表明,该黄绿叶突变体由一隐性核基因控制。进一步利用分子标记将ygl10定位在水稻第10染色体约380kb的区段内。对该区段内存在的ORF进行序列分析,发现编码叶绿素a氧化酶(chlorophyll a oxygenase)基因(OsCAO1)的第9个外显子存在5个碱基缺失,从而导致提前出现终止密码子,推测CAO1即为ygl10的候选基因。
Two mutants with rolled leaves, temporally designated as rl3（t）-I and rl3（t）-2, were served for exploring the mechanism underlying the rolled leaf characteristic. Except for having typical rolled leaves, the plant heights and panicle lengths of rl3（t）-1 and rl3（t）-2 significantly decreased, and the seed-setting rate also decreased when compared with wild type 93-11. Cytological analysis suggested that the rolled leaf phenotype might be caused by the changes of number and size of bulliform cells. Genetic analysis indicated rl3（t）-1 is allelic to rl3（t）-2, and controlled by a recessive gene. Gene mapping result indicated that RL3（t） gene resided in a 46-kb long region governed by the sequence tag site markers S3-39 and S3-36 on rice chromosome 3. The result provides an important clue for further cloning the RL3（t） and understanding the mechanism of rice leaf development.
Rice(Oryza sativa L.)inflorescence(panicle)architecture is an important agronomic trait,serving as one of the determinants of rice yield.A number of genes related to panicle development have been cloned and functionally characterized so far.However,more information is needed for fully understanding of the mechanism underlying the panicle development.In the present study,we identified a clustered spikelets 4(cl4)mutant in the 93-11 genetic background.Compared to its wild-type 93-11,cl4 mutant has a typical clustered spikelets phenotype with all primary branches clustered on the base of the main rachis and 2–3abnormal spikelets clustered on the primary branches.Moreover,cl4 mutant also shows shorter plant height than that of the wild type.Map-based cloning strategy is performed to clone the CL4 gene.As a result,CL4 is demonstrated to encode a putative cytochrome P450 protein CYP724B1,which is involved in brassinosteroid biosynthesis.To confirm our mapping result,the CL4 RNAi transgenic plants are generated.And the transgenic plants also show similar phenotype as the cl4 mutant.These results provide strong evidence that CL4 plays an important role in rice panicle development as well as plant height regulation.
Min GuoYi-Hao YangMin LiuQing-Cai MengXiu-Hong ZengLing-Xia DongShu-Zhu TangMing-Hong GuChang-Jie Yan
