BcMF9, a novel polygalacturonase gene, is required for both Brassica campestris intine and exine formation
BcMF9, a novel polygalacturonase gene, is required for both Brassica campestris intine and exine formation
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BcMF9 是一种新型多聚半乳糖醛酸酶基因，是甘蓝内壁和外壁形成所必需的
DOI：
10.1093/aob/mcp244
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发表时间：
2009-12-01
期刊：
影响因子：
4.2
通讯作者：
Cao, Jiashu
中科院分区：
文献类型：
--
作者：
Huang, Li;Ye, Yiqun;Cao, Jiashu
多聚半乳糖醛酸酶(PG)基因家族在几个物种的花粉中含量丰富，但目前对PG基因在花粉发育中的作用知之甚少。为了研究PG基因在花粉发育中的确切作用以及该家族的一般情况，从大白菜(Brassica Campestris SSP)中分离到一个可能的PG基因--白菜雄性育性9号(BcMF9)。Chinensis，syn.白菜型油菜B.Rapa Ssp.RT-PCR、Northern印迹和原位杂交分析BcMF9基因的表达模式，并利用反义RNA技术研究该基因的功能。BcMF9在花粉发育后期的绒毡层和小孢子中表达。BcMF9表达降低的反义RNA转基因植株表现出花粉形态缺陷，导致花粉萌发效率降低。透射电子显微镜观察表明，转基因花粉向外的均一果胶外壁层发育过度，主要占据内壁，颠倒了转基因花粉内壁和外壁的正常比例分布。抑制BcMF9还导致先前形成的顶盖和杆状突起从双核阶段开始分裂，这是绒毛过早降解的结果。包括BcMF9的表达模式和表型缺陷在内的一系列证据表明，BcMF9在外壁模式中具有孢子体作用，在内壁形成中具有配子体作用模式。BcMF9可能在绒毡层退化的晚期阶段起到协调器的作用，随后调控壁物质的分泌，进而调节外壁的形成。BcMF9也可能通过调节果胶的动态新陈代谢在内脏形成中发挥作用。
The polygalacturonase (PG) gene family has been found to be enriched in pollen of several species; however, little is currently known about the function of the PG gene in pollen development. To investigate the exact role that the PG gene has played in pollen development and about this family in general, one putative PG gene, Brassica campestris Male Fertility 9 (BcMF9), was isolated from Chinese cabbage (Brassica campestris ssp. chinensis, syn. B. rapa ssp. chinensis) and characterized.RT-PCR, northern blotting and in situ hybridization were used to analyse the expression pattern of BcMF9, and antisense RNA technology was applied to study the function of this gene.BcMF9 is expressed in particular in the tapetum and microspore during the late stages of pollen development. Antisense RNA transgenic plants that displayed decreased expression of BcMF9 showed pollen morphological defects that resulted in reduced pollen germination efficiency. Transmission electron microscopy revealed that the homogeneous pectic exintine layer of pollen facing the exterior was over-developed and predominantly occupied the intine, reversing the normal proportional distribution of the internal endintine layer and the external exintine in transgenic pollen. Inhibition of BcMF9 also resulted in break-up of the previously formed tectum and baculae from the beginning of the binucleate stage, as a result of premature degradation of tapetum.Several lines of evidence, including patterns of BcMF9 expression and phenotypic defects, suggest a sporophytic role in exine patterning, and a gametophytic mode of action of BcMF9 in intine formation. BcMF9 might act as a co-ordinator in the late stages of tapetum degeneration, and subsequently in the regulation of wall material secretion and, in turn, exine formation. BcMF9 might also play a role in intine formation, possibly via regulation of the dynamic metabolism of pectin.