Roles of Arabidopsis Patatin-Related Phospholipases A in Root Development Are Related to Auxin Responses and Phosphate Deficiency  

作　　者：Steffen Rietz Georgi Dermendjiev Esther Oppermann Fikadu Getah Tafesse Yunus Effendi Andre Holk Jane E. Parker Markus Teige Gunther F.E. Scherer 

机构地区：[1]Max Planck Institute for Plant Breeding Research, Department of Plant Microbe Interactions, Carl von Linne Weg 10, D-50829 Cologne, Germany [2]Leibniz University Hannover, Molecular Developmental Physiology, Herrenhauser Str. 2, D-30419 Hannover, Germany [3]University of Vienna, MFPL, Department of Biochemistry, Dr. Bohrgasse 9, A-1030 Wien, Austria [4]Present address: University of Utrecht, Department of Membrane Enzymology, Inst. Biomembranes, Padualaan 8, NL 3584 CH Utrecht. The Netherlands

出　　处：《Molecular Plant》2010年第3期524-538,共15页分子植物（英文版）

摘　　要：Phospholipase A enzymes cleave phospho- and galactolipids to generate free fatty acids and lysolipids that function in animal and plant hormone signaling. Here, we describe three Arabidopsis patatin-related phospholipase A （pPLA） genes AtPLAIVA, AtPLAIVB, and AtPLAIVC and their corresponding proteins. Loss-of-function mutants reveal roles for these pPLAs in roots during normal development and under phosphate deprivation. AtPLAIVA is expressed strongly and exclusively in roots and AtplalVA-null mutants have reduced lateral root development, characteristic of an impaired auxin response. By contrast, AtPLAIVB is expressed weakly in roots, cotyledons, and leaves but is transcriptionally induced by auxin, although AtplalVB mutants develop normally. AtPLAIVC is expressed in the floral gynaecium and is induced by abscisic acid （ABA） or phosphate deficiency in roots. While an AtplalVC-1 loss-of-function mutant displays ABA respon- siveness, it exhibits an impaired response to phosphate deficiency during root development. Recombinant AtPLA proteins hydrolyze preferentially galactolipids and, less efficiently, phospholipids, although these enzymes are not localized in chloroplasts. We find that AtPLAIVA and AtPLAIVB are phosphorylated by calcium-dependent protein kinases in vitro and this enhances their activities on phosphatidylcholine but not on phosphatidylglycerol. Taken together, the data reveal novel functions of pPLAs in root development with individual roles at the interface between phosphate deficiency and auxin signaling.Phospholipase A enzymes cleave phospho- and galactolipids to generate free fatty acids and lysolipids that function in animal and plant hormone signaling. Here, we describe three Arabidopsis patatin-related phospholipase A （pPLA） genes AtPLAIVA, AtPLAIVB, and AtPLAIVC and their corresponding proteins. Loss-of-function mutants reveal roles for these pPLAs in roots during normal development and under phosphate deprivation. AtPLAIVA is expressed strongly and exclusively in roots and AtplalVA-null mutants have reduced lateral root development, characteristic of an impaired auxin response. By contrast, AtPLAIVB is expressed weakly in roots, cotyledons, and leaves but is transcriptionally induced by auxin, although AtplalVB mutants develop normally. AtPLAIVC is expressed in the floral gynaecium and is induced by abscisic acid （ABA） or phosphate deficiency in roots. While an AtplalVC-1 loss-of-function mutant displays ABA respon- siveness, it exhibits an impaired response to phosphate deficiency during root development. Recombinant AtPLA proteins hydrolyze preferentially galactolipids and, less efficiently, phospholipids, although these enzymes are not localized in chloroplasts. We find that AtPLAIVA and AtPLAIVB are phosphorylated by calcium-dependent protein kinases in vitro and this enhances their activities on phosphatidylcholine but not on phosphatidylglycerol. Taken together, the data reveal novel functions of pPLAs in root development with individual roles at the interface between phosphate deficiency and auxin signaling.

关 键 词：Abiotic/environmental stress hormonal regulation protein phosphorylation/dephosphorylation SIGNALTRANSDUCTION gene regulation Arabidopsis. 

分 类 号：Q344.13[生物学—遗传学] S572[农业科学—烟草工业]