【作者】 张鹏；

【导师】 周永明； 范楚川；

【作者基本信息】 华中农业大学 ， 作物遗传育种， 2012， 硕士

【摘要】 磷脂是生物膜的重要组成成份之一。磷脂不仅是细胞质与外界的屏障,还广泛参与细胞内外的信号转导,在诸如茉莉酸的合成、细胞延伸的调控等方面发挥重要作用。因此,作为水解磷脂的磷脂酶在植株的生长发育方面可能也发挥着重要的作用。拟南芥PLP9(Patatin-like phospholipase9)属于磷脂酶基因家族中的类patatin型PL A (Phospholipase A),目前对其功能还了解不多。在本研究中,我们以PLP9的T-DNA突变体(PLP9-knockout, PLP9-KO)和超量表达植株(PLP9-overexpression,PLP9-OE)为材料,通过植物形态学观察、细胞显微技术和化学成分分析,比较了它们与野生型(Wild type, WT)在形态学和细胞学等方面的差异,旨在为深入了解拟南芥PLP9的功能提供实验依据。主要研究结果如下：1.PLP9参与调控植株形态的建成。与WT相比,PLP9-OE的整个植株明显变得矮小,茎秆和下胚轴增粗,叶片变厚且出现皱缩。对不同器官长度的测量发现,PLP9-OE的叶片、角果、花器官以及下胚轴都显著变短,而在PLP9-KO中相应器官较WT有所增长。2.PLP9参与调控拟南芥细胞延伸。对叶片表皮细胞、茎秆细胞和下胚轴表皮细胞的显微观察发现,PLP9-OE材料中这些组织的细胞长度都明显变短且细胞宽度有所增加,而PLP9-KO中相应细胞的长度则增加。表明PLP9可能参与了细胞延伸的调控。3.PLP9参与调控拟南芥茎秆的机械强度。对成株期的茎秆强度测定结果表明PLP9-OE的抗折力显著低于WT,而PLP9-KO则显著高于WT。进一步测量它们的细胞壁成分,发现PLP9-OE中的木质素含量低于WT,而PLP9-KO中的木质素、纤维素以及半纤维素的含量都显著高于WT。对茎秆的细胞显微观察发现PLP-KO的束间纤维细胞较WT增长、细胞壁加厚；而在PLP9-OE中则存在相反的趋势。这些结果表明PLP9通过改变茎秆中的细胞壁成分和结构来调节茎秆的机械强度。4.PLP9基因的功能验证。将拟南芥PLP9在甘蓝型油菜中过量表达,发现转基因油菜中也表现出叶片肥厚且皱缩、花器官变短等与拟南芥PLP9-OE相似的表型。由此表明该基因在甘蓝型油菜中也可以发挥相似的功能。以上结果表明,拟南芥PLP9基因在植株形态建成、细胞延伸和茎秆机械强度的调控等方面发挥着重要的作用。本研究结果为进一步阐明该基因的作用机理提供了新信息,也丰富了对PLP家族基因的功能的整体认识。更多还原

【Abstract】 Phospholipid is major and vital cellular constituents of cell membrane, which governs the intercharge of information and metarials between intracellular and extracellular environment. Phospholipid-derived products have being reported involving many cellular processes including biosynthesis of jasmonic acid and cell elongation. So, phospholipase plays an important role in those processes.PLP9belong to Patatin-like phospholipase A (PLP) family. Here, we explored phenotypes of the PLP9-related mutants using histological, anatomical and chemical methods and uncover the function of the PLP9in Arabidopsis.The main results are as follows:1. PLP9involves in regulating plant morphology. The plant size of young PLP9-OE is much smaller than WT, and its rosettes are more compact. In adult-plant stage, PLP9-OE shows an extremely dwarf phenotype, and the stalks are wider in PLP9-OE but more norrow in PLP9-KO comparing WT. The leaves of PLP9-OE are much thicker than that of WT. Based on the measurement of different organ length, we found that PLP9-OE had shorter main inflorescence stalks comparing with WT and other organs are also short including leaves, siliques, flowers and hypocotyls, but PLP9-KO has opposite trend in those aspects.2. PLP9involves in regulating cell elongation. The results from microscopic examination show that cells are longer in PLP9-KO and shorter in PLP9-OE compared with WT, respectively. Thus, PLP9involves in regulating cell elongation.3. PLP9involves in regulating mechanical strength. PLP9-OE had fragile stems. Measurement of breaking force showed that it need less force to break stalks of PLP9-OE, and that of PLP9-KO is larger. According to the chemical results, PLP9-OE had less lignin content than WT, whereas in PLP9-KO the content of cell wall materials is higher. Anatomical results showed that, the cells in interfascicular fiber of PLP9-KO are longer that that of WT, and they also have thicker cell wall, while the situation in PLP9-OE is different. 4. Verification of the gene function.When overexpress the PLP9of Arabidopsis in Brassica napus L., some of phonetypes found in PLP9-OE are also exhibited in transgenic plants.Our result provide direct evidences for analyzing the function of PLP9, and help people have a clear view of function of PLP family.更多还原