Functional Characterization of Arabidopsis Phosphatidylinositol Monophosphate 5-kinase 2 in Lateral Root Development, Gravitropism and Salt Tolerance (Springer Theses Book 417)

Annotation The functional characterization of a key enzyme in the phosphatidylinositol (PI) signaling pathway in the model plant Arabidopsis thaliana is the focus of the research summarised in this thesis. Moreover, a particular focus is the exploration of the biological functions of Arabidopsis phophatidylinositol monophosphate 5-kinase 2 (PIP5K2) which catalyzes the synthesis of phophatidylinositol (4,5) bisphosphate, the precursor of two important second messengers (inositol 1,4,5-trisphosphate and diacylglycerol). Through molecular and genetic approaches, the author isolated and characterized the expression pattern, physiological functions and the underlying mechanism of Arabidopsis PIP5K2. It is found that PIP5K2 is involved in regulating lateral root formation and root gravity response through modulating auxin accumulation and polar auxin transport and also plays a critical role in salt tolerance. These findings shed new light on the crosstalk between PI signaling and auxin response, both of which have crucial regulatory roles in plant development The functional characterization of a key enzyme in the phosphatidylinositol (PI) signaling pathway in the model plant Arabidopsis thaliana is the focus of this thesis. Moreover, a particular focus is the exploration of the biological functions of Arabidopsis phosphatidylinositol monophosphate 5-kinase 2 (PIP5K2), which catalyzes the synthesis of phosphatidylinositol (4,5) bisphosphate, the precursor of two important second messengers (inositol 1,4,5-trisphosphate and diacylglycerol). Employing molecular and genetic approaches, the author isolates and characterizes the expression pattern, physiological functions and underlying mechanism of Arabidopsis PIP5K2. In doing so, he reveals that PIP5K2 is involved in regulating lateral root formation and root gravity response through modulating auxin accumulation and polar auxin transport, and also plays a critical part in salt tolerance. These findings shed new light on the crosstalk between PI signaling and auxin response, both of which fulfill crucial regulatory roles in plant development Supervisor's Foreword; Abstract; Acknowledgments; Contents; About the Author; 1 Review of Phosphatidylinositol Phosphate Kinase in Phosphatidylinositol Signaling Pathway; Abstract; 1.1emspBrief Introduction of Phosphatidylinositol Signaling Pathway; 1.2emspPhosphatidylinositol Phosphate Kinase and Phosphatidylinositol Bisphosphate in Phosphatidylinositol Pathway; 1.2.1 Classification of PIPKs; 1.2.2 Substrates and Products of PIPKs; 1.2.3 Regulation of PIPKs; 1.2.4 Biological Functions of PIPKs; 1.3emspResearch Progresses of PIPKs in Higher Plants; 1.3.1 PIPKs in Oryza Sativa Front Matter....Pages i-xix Review of Phosphatidylinositol Phosphate Kinase in Phosphatidylinositol Signaling Pathway....Pages 1-16 Structure and Expression Pattern Analysis of Arabidopsis PIP5K2 ....Pages 17-28 Arabidopsis PIP5K2 Is Involved in Lateral Root Development Through Regulating Auxin Accumulation....Pages 29-43 Arabidopsis PIP5K2 Is Involved in Root Gravitropism Through Regulation of Polar Auxin Transport....Pages 45-62 Arabidopsis PIP5K2 Is Involved in Salt Tolerance....Pages 63-77