Functional Analysis Of Arabidopsis Root Hair Development Related Gene SRH1

Based on candidate genes picked from LCM (Laser Capture Microdissection)-microarray(Affymetrix GENECHIP system) analysis for H cell, N cell and cortex, a T-DNA instertional Arabidopsis mutant with defect in root hair elogation was isolateded and named as srh1 (Short Root Hair 1). In response to phosphate starvation or addition of external hormones, srhl is similar with wide type(WT) except its weakness in root hair elongation. Microarray and q-RT-PCR analysis revealed that a function-loss results in a few genes to shift in expression level. Our result show that SRH1 was located in plasma membrane, and that a microfiber disorder was detected in root hair tip. Expression level of RHD2 encoding NADPH oxydase for root hair initiation was upregulated in srh1 mutant. Then the double mutants srh1/rhd2, srh1/scn1, the triple mutant srh1/rhd2/scn1 were developed for genetic and phenotyping analysis. The results suggest that SRH1 is involved vesicle trafficking or cell wall construction.Gene cloning and bioinformatics analysis indicate that SRH1 is a member of Beach protein. It's the first report that Beach protein affected in root hair development, and also the first gene with a known function in plant Beach family.