Primary Study Of UDP-L-rhamnose Biosynthesis Gene RHM1 In Arabidopsis Thaliana

L-Rhamnose (Rha) is a component of the plant cell wall pecticpolysaccharidesrha mnogalacturonan I (RG-I) and rhamnogalacturonan II (RG-II). In this paper, we studied the function of RHM1 with molecular biology and physiological approaches.Expression studies with AtRHM1 promoter-GUS fusion gene showed that AtRHM1 was expressed almost ubiquitously, with stronger expression in roots and cotyledon of young seedlings and inflorescences. The GUS staining and GUS enzymatic activity assay showed that the expression of AtRHM1 is induced at transcriptional level by glucose and wounding.To identify the regulatory elements in AtRHM1 promoter, we created a series of deletions of AtRHM1 promoter ranging from -931bp to +427bp. The full length of the promoter and its deletion derivatives fused with GUS reporter gene were introduced into wild-type Arabidopsis by Agrobacterium-mediated transformation, respectively. The GUS staining and GUS enzymatic activity assay showed that the regulatory elements involved in the glucose and wounding response are located in the region of -931bp～-752bp, -752～-308bp respectively.The overexpression and mutation of AtRHM1 in Arabidopsis have no effect on phenotype.