Screening And Map-based Cloning Of A Gene Controlling Pavement Cells Development In Arabidopsis

Pavement cells are the most abundant epidermal cell type of leaves.They are important for the research of cell division,polarity maintenance,fate determination and morphogenesis.The pavement cells have been the ideal model for studying fate decision and morphogenesis of plant cells.We screened EMS-mutagenized seeds of Arabidopsis by light microscopy,a mutant with pavement cells development defect was isolated.The morphology of G39 is different from Col.G39 is a semi-dominant mutant by single gene controlled. We studied the phenotype and physiological features of G39 preliminarily,and mapped the mutant gene by map-based cloning.G39 is dwarf,late-flowering,with curly leaves,curly petals and siliques.It's pollen fertility is reduced.Most importantly,G39 displays defection in pavement cell shape,the lobe number and lobe length are reduced.The trichromes become flat and spiral.Stomatal density and stomatal index in abaxial epidermis are also reduced.The application of GA can partially rescued the mutant phenotype of plant and pavement cells in G39.Exogenous GA promoted the elongation of hypocotyls and roots,but PAC(the inhibitor of GA synthesis) can't inhibit the elongation of hypocotyls and roots effectively.By map-based cloning technique,we mapped the mutant gene to a region of 90Kb on the right arm of chromosome 2.Then,we gained three candidate genes by sequencing this region directly.