【作者】 王继荣；

【导师】 吴平；

【作者基本信息】 浙江大学 ， 生物化学与分子生物学， 2008， 硕士

【摘要】 植物生长素调控细胞的分裂与分化,同时在植物向性生长与维持植物的顶端优势中发挥重要作用。生长素极性运输是通过载体蛋白在质膜和内涵体的定位来调控的。植物生长素输出载体(efflux carrier)PIN-FORMED基因组织表达是证明植物生长发育所需生长素浓度梯度的最好工具。本文通过RT-PCR与转基因方法研究水稻PIN(OsPIN)家族基因的表达模式,及其受激素与养分环境的影响。得到以下结果:1.OsPIN家族目前共发现9个成员,OsPIN家族蛋白结构包含两个疏水区和中间一个亲水区,且每个疏水区有五次跨膜折叠,两个跨膜区具有高度保守性,在第二个疏水区有一NPXXY的保守结构,此结构对内吞作用中的膜蛋白与受体蛋白的互作非常重要。2.OsPIN家族基因的表达存在一定的特异性。在茎、叶与颖壳中OsPINs基因主要集中在维管组织表达。在根中,OsPIN1b主要在根冠与中柱中表达,OsPIN4与OsPIN9主要在侧根原基与中柱中表达,其余基因主要在根分生区表达。同时OsPIN1b、OsPIN4与OsPIN9在不定根原基也有表达。3.OsPIN家族基因在根中的表达受到一定浓度的生长素与乙烯的诱导。4.氮、磷等营养对OsPIN家族基因的表达没有普遍的影响,但在缺氮再施加铵态氮短期处理后OsPIN5b的表达明显受到诱导,而缺磷抑制OsPIN4的表达。且此结果不受pH值影响。依据该结果推断铵态氮与磷饥饿信号可能参与生长素信号调控途径。更多还原

【Abstract】 Phytohormone auxin is implicated in regulating the pattern of cell division and differentiation,and also plays an important role in plant tropisms and apical dominance.Polar transport of the auxin is mediated by plasma-membrane and endosome localized carrier proteins.PIN proteins are the well studied auxin efflux components implicated in the establishment of the auxin gradient required for growth and development of plants.In this study,we analyzed the expression patterns of OsPINs and the response to auxin and nutrients using RT-PCR and transgenic plants with GUS report gene.The results are summarized as follows:1.Rice（Oryza sativa L.） genome contains 9 PIN proteins.All OsPINs contain two hydrophobic domains（each with five transmembrane helices） separated by a hydrophilic loop.There is an internalization motif NPXXY in the second hydrophobic domain.This motif represents a conserved part of the sequence, which is important for the interaction of the transmembrane protein with the adaptor proteins during clathrin-dependent endocytosis.2.Our research revealed the overlapping but distinct expression patterns of these OsPIN genes.Histochemical analysis of promoter-driven GUS expression in transgenic rice showed a predominant activity in the vascular tissues of stem,leaf and panicle.There are predominant activity in root cap,stele and adventitious root primodia of OsPIN1b,lateral root primodia,stele and adventitious root primodia of OsPIN4 and OsPIN9,and the zone of cell division of another OsPIN genes.3.The expression of OsPINs in root are significantly induced by exogenous auxin and ethylene.4.There was no overall response of OsPINs to nitrogen and phosphorus,but the expression of OsPIN5b was significantly induced by NH₄⁺ after pretreated with nitrogen starvation,and expression of OsPIN4 was reduced by Pi-starvation.The result indicate that NH₄⁺-N and Pi-starvation signaling is involved in AUX signaling.更多还原