Clone And Functional Analysis Of BRs Related Genes In Flax (Linum Usitassimum L.)

Brassinosteroids was an important sterols hormones for plant development.Flax was a textile,industrial,medicinal materials,which had a very high economic value.The yield and quality of fiber was decided by the plant height and fiber length of flax.DWF4 was a key enzyme in BR biosynthetic pathway which participated in the regulation of BR synthesis pathway.BRI1 and BES1 were the receptor proteins and transcription factors in BR signal transduction pathway,which were involved in the regulation of BR signal transduction pathway.The materials were Fanny,Col-0 and bril-301 in this study.The LuDWF4,LuBRI1 and LuBES1 genes were cloned from the flax by homology-based cloning and the function was analysed in Arabidopsis.The expression of genes related to cell wall formation was analysed in the rapid growth stage of flax.The main conclusions were as follows:?1?The full-length sequences of LuDWF4,LuBRI1,cLuBES1 and gLuBES1 genes were 1479 bp,3579 bp,978 bp and 1428 bp.?2?The plant expression vectors were constructed successfully and the transgenic plants meeting the 3:1 segregation ratio of LuDWF4,LuBRI1 and gLuBES1 were 4 lines(D₂,D₉,D₁₀,D₁₆),3 lines(BR₃,BR₄,BR₁₂)and 3 lines(BE₁,BE₄,BE₁₁),respectively.?3?Overexpression the LuDWF4 in Col-0 promoted plant growth including the plant height and pedicels increased and flowering in advance.The dwarf phenotype of bril-301 was restored by over-expressing the LuBRI1 gene or LuBES1 gene.The hypocotyl elongation of Col-0,bril-301 and transgenic lines of LuBRI1 and gLuBES1 were improved by epiBL in the light and dark.?4?The cell walls of bast fiber had not processed secondary thickening in the stem at fast growth stage and the thickness were TOP<MID<BOT.LuBGAL3,LuBGAL5,LuBGAL6,LuBGAL9,LuCESA1,LuCESA3,LuCESA9,LuCESA10 mainly promoted cell elongation of cell wall in flax;LuBGAL1 played an important role in cell wall thickening;LuSuSy and LuXTH4 also took part in the development of cell wall.