Phenotypic Identification Of Arabidopsis Phospholipase PLP9-related Mutants

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.