Two duplicate CYP704B1-homologous genes BnMs1 and BnMs2 are required for pollen exine formation and tapetal development in Brassica napus
Two duplicate CYP704B1-homologous genes BnMs1 and BnMs2 are required for pollen exine formation and tapetal development in Brassica napus
复制标题
甘蓝型油菜花粉外壁形成和绒毡层发育需要两个重复的 CYP704B1 同源基因 BnMs1 和 BnMs2
DOI：
10.1111/j.1365-313x.2010.04289.x
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发表时间：
2010-09-01
期刊：
影响因子：
7.2
通讯作者：
Fu, Tingdong
中科院分区：
文献类型：
--
作者：
Yi, Bin;Zeng, Fangqin;Fu, Tingdong
S45A 是甘蓝型油菜 BnMs1 和 BnMs2 基因座的双隐性突变体，在成熟花药中不产生花粉，并且通过自花受精不产生种子。 BnMs1和BnMs2基因在控制雄性育性方面具有冗余功能，分别位于连锁群N7和N16上，基于拟南芥和芸苔属之间的共线性，它们位于拟南芥1号染色体上的同一位点。互补测试表明，一个候选基因 BnCYP704B1（细胞色素 P450 家族的成员）可以挽救雄性不育。对发育中的花药的扫描电子显微镜（SEM）和透射电子显微镜（TEM）显示，突变体的花粉壁形成严重受损，缺乏孢粉质或外壁。该表型首先在花药发育的四分体阶段（第7阶段）出现，与在第7-8阶段（单倍体阶段）绒毡层细胞中观察到的最大BnCYP704B1 mRNA积累一致。 TEM 还表明，由于 S45A 突变体中脂质代谢紊乱，绒毡层的发育存在严重缺陷。 TUNEL 测定表明 S45A 突变体绒毡层中的程序性细胞死亡模式有缺陷。脂质分析显示，S45A突变体中总脂肪酸含量降低，表明BnCYP704B1参与脂质代谢。这些数据表明，BnCYP704B1 参与重要的绒毡层特异性代谢途径，该途径不仅涉及外壁形成，而且也是基本绒毡层细胞发育和功能所必需的。
S45A, a double recessive mutant at both the BnMs1 and BnMs2 loci in Brassica napus, produces no pollen in mature anthers and no seeds by self-fertilization. The BnMs1 and BnMs2 genes, which have redundant functions in the control of male fertility, are positioned on linkage groups N7 and N16, respectively, and are located at the same locus on Arabidopsis chromosome 1 based on collinearity between Arabidopsis and Brassica. Complementation tests indicated that one candidate gene, BnCYP704B1, a member of the cytochrome P450 family, can rescue male sterility. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) of the developing anther showed that pollen-wall formation in the mutant was severely compromised, with a lack of sporopollenin or exine. The phenotype was first evident at the tetrad stage (stage 7) of anther development, coinciding with the maximum BnCYP704B1 mRNA accumulation observed in tapetal cells at stages 7-8 (haploid stage). TEM also suggested that development of the tapetum was seriously defective due to the disturbed lipid metabolism in the S45A mutant. A TUNEL assay indicated that the pattern of programmed cell death in the tapetum of the S45A mutant was defective. Lipid analysis showed that the total fatty acid content was reduced in the S45A mutant, indicating that BnCYP704B1 is involved in lipid metabolism. These data suggest that BnCYP704B1 participates in a vital tapetum-specific metabolic pathway that is not only involved in exine formation but is also required for basic tapetal cell development and function.