微管骨架在北方杂草稻中胚轴伸长过程中的作用及其机制

发布时间：2019-01-29 19:17

【摘要】：水稻中胚轴长度是影响水稻出苗的重要因素之一。栽培稻中胚轴伸长存在一定的亚种间差别,多数籼稻中胚轴伸长能力较强,而粳稻中胚轴伸长能力比较弱。前期研究发现具有粳稻遗传背景的杂草稻(Oryza sativa f. spontanea L.)——WR04-6和WR04-43具有较长的中胚轴,但其中胚轴伸长的作用机制还不清楚。水稻中胚轴生长由细胞生长、分裂和形态建成等过程决定。微管骨架是细胞骨架的主要组成部分,在细胞的生长、分裂和形态建成中起到重要作用。然而,水稻中胚轴伸长过程中微管的作用尚不明确。本研究以2种杂草稻WR04-6和WR04-43为研究试材,栽培稻日本晴为对照,阐明通过微管解聚介导赤霉素(GA)含量使杂草稻中胚轴伸长的作用机制。主要的研究结果如下：1.在微管特异性解聚药剂oryzalin (25 nM)处理下,3种水稻中胚轴和中胚轴细胞的长度均显著增加。相反,在微管稳定药剂taxol(1μM)的处理下,中胚轴长度和中胚轴细胞的长度均显著下降。2.与日本晴相比,杂草稻在中胚轴伸长前期,其中胚轴细胞表现更明显的微管解聚,以及随后微管的横向排列。3.杂草稻中胚轴伸长前期,微管解聚刺激了内源GA含量的增加,并且诱导了GA合成基因GA3ox2、GA20ox2和GID1基因表达量的升高。4.通过分析15个微管结合蛋白基因,3个OsKatanin(微管切割蛋白)亚基基因在杂草稻中胚轴伸长前期表达量显著升高。5.将OsKatanin p60s基因分别在栽培稻日本晴中过表达,发现过表达植株中胚轴和中胚轴细胞均显著伸长。微管的动态变化、GA含量和GA合成基因的变化与杂草稻类似。综上所述,微管的动态变化对北方杂草稻中胚轴伸长起了重要的调节作用,其中微管解聚介导OsKatanin可能通过调节GA的合成和信号转导刺激内源GA含量的增加,从而促进中胚轴的伸长。
[Abstract]:The length of rice mesocotyls is one of the important factors affecting rice seedling emergence. There were some subspecies differences in the elongation of mesocotyl of cultivated rice. Most indica rice had strong elongation ability of mesocotyls, while japonica rice had weak elongation ability of mesocotyls. Genetic background of Weed Rice (Oryza sativa f. in Japonica Rice Spontanea L.)-WR04-6 and WR04-43 have long mesocotyls, but the mechanism of elongation is unclear. The growth of rice mesocotyls is determined by cell growth, division and morphogenesis. Microtubule cytoskeleton is the main component of cytoskeleton and plays an important role in cell growth, division and morphogenesis. However, the role of microtubules in the elongation of rice mesocotyls is unclear. In this study, two kinds of weedy rice (WR04-6 and WR04-43) were used as the experimental materials and the cultivated rice (Nippon) as control. The mechanism of microtubule-mediated gibberellin (GA) content in the mesocotyls of weedy rice was discussed. The main results are as follows: 1. Under the treatment of microtubule-specific depolymerization agent oryzalin (25 nM), the length of mesocotyls and mesocotyl cells of three rice varieties increased significantly. On the contrary, the length of mesocotyls and the length of mesocotyl cells decreased significantly under the treatment of microtubule stabilizer taxol (1 渭 M). The microtubule depolymerization of Hypocotyl cells and the transversal arrangement of microtubules were more obvious in the early stage of elongation of Hypocotyl than in Nippon clear. The microtubule depolymerization stimulated the increase of endogenous GA content and induced the expression of GA synthase genes GA3ox2,GA20ox2 and GID1 in the early stage of elongation of mesocotyl of weedy rice. 4. Through the analysis of 15 microtubule-binding protein genes, 3 OsKatanin subunits were expressed significantly in the early stage of elongation of the mesocotyls of weedy rice. The OsKatanin p60s gene was overexpressed in Japanese rice, and it was found that both the mesocotyls and the mesocotyl cells were significantly elongated. The dynamic changes of microtubules, the changes of GA content and GA synthesis genes were similar to those of weedy rice. In conclusion, the dynamic changes of microtubules play an important role in regulating the elongation of mesocotyl of weedy rice in North China, in which microtubule depolymerization mediated OsKatanin may stimulate the increase of endogenous GA content by regulating the synthesis of GA and signal transduction. Thus promoting the elongation of the mesocotyls.
【学位授予单位】：沈阳农业大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：S451

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