Genetic Analysis And Gene Identification Of A Glabrous Rice Mutant Gl6

Glabrous leaf refers to the loss of epidermis on the surfaces of leaves and seed hulls.Epidermal trichomes form a natural physical barrier on the surface of plants that helps plant to resist the invasion of pests and diseases,prevent radiation damage,reduce water loss,and help plant to respond to various biological and abiotic stresses.In rice two genes OsWOX3B and HL6 are reported that controls the epidermal trichome growth.In rice epidermal trichome growth and development of mechanisms are not yet clear.In this study a Yixiang 1B?indica maintainer line?was used as parent material for EMS mutagenesis and obtained a glabrous leaf mutant glabrous leaf 6?gl6?.We primarily mapped target gene and then SNP locus was found by whole genome resequencing.Cloning of gl6 that controls rice trichome development provide new clues.Our main findings are as follows:1.The leaf blade surface of the mutant gl6 has no trichome epidermal trichome growth.There was no significant difference in agronomic traits between the mutant gl6 and the wild type,but the thousand grain weight of the mutant gl6 was significantly reduced,leaves were yellow and premature,and the tips of the leaves were found dried and ultimately lead to death after salt stress.2.Genetic analysis showed that mutant gl6 phenotype was controlled by a single recessive nuclear gene.The F₂?gl6/Nipponbare?mapping population revealed that gl6 was primarily mapped in region of 701kb between InDel marker 2-8 and 2-9.BC₁F₂?gl6/Yixiang?population MutMap analysis revealed a SNP?397th bp was changed from C to T?in CDS of LOC_Os06g45630 gene that results in change of amino acid from proline to serine.3.Analysis of ABA hormone content of gl6 mutant had significantly higher than that of the wild type.The POD and CAT enzyme activities were analyzed that showed gl6mutants was lower than the wild type,but the SOD enzyme activity of the mutant gl6 was significantly higher than that of the wild type.Chlorophyll contents were higher in gl6mutant than the wild type.4.Scanning electron microscopy of wild type grain hull surface has anmacrohairs and sharp protruding structure of microhairson its leaf blade.While,gl6 mutant surface of grain hull showed no trichome and protruding structure was absent on leaf blade.5.We observed trichomes on epidermis by paraffin analysis in wild type while mutant showed absence of trichomes.The gl6 mutant has reduced number of mesophyll cells and reduced leaf thickness than wild type.6.qRT-PCR analysis showed gl6,OsWOX3B,and HL6 gene expression in gl6 mutant is significantly lower than wild type.ABA synthesis and metabolic pathway related genes OsNCED5 and OsABA8ox1 was high in mutant gl6 than that of wild type.7.Complementary transgenic seedlings have been obtained by constructing complementary vectors.Since at seedling stage phenotype cannot be effectively identified,as gl6 growth and development expression can be identified after the seedlings mature.