Screening And Isolation Of Two Trichom Developmental Mutants In Arabidopsis Thaliana

Trichomes,which differentiate from epidermal cells,cover most of the aerial parts of terrestrial plants.Trichome serves as a barrier between plants and the environment,and plays very important roles in protecting plants from environment stress.Trichome also has economic value,for instance,the cotton fiber is the trichome of the cotton ovule.Some secretory trichome can synthesize some metabolites such as alkaloid,aromatic oil and resin,which is widely used in medicine,food and cosmetics industries.Trichome is considered as an elegant model system for studying cell fate specification.Therefore,revealing the key factors,as well as their molecular regulation mechanisms involved in controlling trichome cell initiation and development,have very important values both in theoretical and application levels.Here,two trichome mutants vat-002-07 and M28-12 were isolated through large-scale screening by phenotypic observation,genetic analysis and gene cloning.The main results obtained are as follows:1.vat-002-07 shows no trichomes on the first two rosette leaves,and number of trichomes increases on later leaves compared with wild type(WT).After bolting,there is no trichome on the base of the stem,and trichomes on later internodes of the stem are sparser than in WT.The mutant gene was cloned by TAIL-PCR,and the result of BLAST analysis reveals that the T-DNA was inserted into the promoter region of AT3G27920(GL1).2.Compared with WT,M28-12 single shows clumpy secondary inflorescence,dysplastic flowers and trichomes,lower fertility,curling leaves and dwarf plant size.After bolting,bubble-shaped trichomes cover the surface of some organs such as the the upper stem,pedicles and siliques.Using the map-based cloning approach,M28-12 mutation site was mapped to ainternal spanned 44 kb on chromosome 1.We sequenced the 18 genes in this aregion and found that the 955 th base of AT1G78570 was mutated from G to A,which converted Gly165 to Asp165.Taken together,this work provided new genetic materials for studying the function of the mutant gene and laid the foundation for the future research on the biochemical mechanisms of trichome cell initiation and development.