The Role To Develop Of Transcription Factors GbSPL31/59/16 In Cotton Fibers

Cotton is one of the most important cash crops in the world and plays an important role in the development of the world economy.The growth and development of cotton fiber affect the yield and quality of cotton,but the molecular mechanism of cotton fiber development is still unclear.Transcription factors that regulate fiber development are important genes involved in cotton fiber development.It is an important way to improve fiber quality to mine key genes involved in cotton fiber development.Previous studies have shown that transcription factor SPL is involved in plant skin,flowering regulation,flowering transition and other developmental processes.Based on the analysis of transcriptome data of Gossypium barbadense cotton at different developmental stages in the previous period,we found that transcription factor SPL may be involved in regulating the development of cotton fibers.This study identified and analyzed the SPL family of Gossypium barbadense.The full-length coding regions of the key candidate genes GbSPL59,GbSPL16 and GbSPL31 were cloned,and their gene functions were verified.Specific research results are as follows:1.Analysis of SPL family of Gossypium barbadenseA total of 59 GbSPLs genes were identified from Gossypium barbadense,and they were distributed on 20 chromosomes.These genes belonged to 7 different evolutionary branches,and the exon composition of the members of different evolutionary branches was very different,but the GbSPLs genes with close relatives had similar exon structure composition.There are three conserved motifs in GbSPLs protein.Fragment replication was the main factor of GbSPLs family expansion.Transcriptome data analysis showed that 9 GbSPLs genes(GbSPL31/5/8/11/16/20/46/59/21)showed obvious expression specificity compared with other genes at the same stage of cotton fiber development.The expression patterns of these 9GbSPLs genes and 7 GbSPLs genes from different evolutionary branches with different gene structures were verified by q RT-PCR.The results showed that GbSPL31/5/6/9/11 was highly expressed in the initiation,elongation and maturity stages of cotton fiber development.The expression was low in the secondary wall thickening stage.GbSPL16/46/7/8/10 was highly expressed in the initial stage and maturity stage,but was low expressed in elongation stage and secondary wall thickening stage.GbSPL59 was highly expressed in extensional phase;GbSPL20 was highly expressed at the beginning and end of elongation.GbSPL21 was expressed in late elongation and maturity.GbSPL28/42 was only expressed in the initial stage.GbSPL23 was only expressed at the mature stage.Combined with the results of expression pattern analysis,gene structure characteristics and previous studies,it is speculated that GbSPL31,GbSPL16 and GbSPL59 may be involved in the regulation of cotton fiber development.2.Cloning and subcellular localization pattern analysis of GbSPL31/59/16 in Gossypium barbadenseThe CDS of GbSPL59,GbSPL16 and GbSPL31 genes were successfully cloned with the total length of 549 bp,984 bp and 3246 bp,respectively.Subcellular localization results showed that the proteins encoded by GbSPL59,GbSPL16 and GbSPL31 genes were all localized in the nucleus,cytoplasm and cell membrane.3.Functional analysis of GbSPL31/59/16 genes in Gossypium barbadenseThe phenotypic differences between transgenic plants and wild-type plants were compared and analyzed,and no significant phenotypic changes were found in GbSPL59 and GbSPL16.However,the GbSPL31 transgenic Arabidopsis thaliana showed obvious phenotypic changes,which showed that the surface fur on the leaves,petiole and stem increased significantly,and the surface fur appeared on the inside of the flower stalk,pistil and sepal.Real-time fluorescence quantitation found that the expression trend of GbGA20 ox,a key gene for gibberellin synthesis,was consistent with that of GbSPL31 during fiber development.It was speculated that GbGA20 ox might regulate the expression of GbSPL31 by affecting the content of gibberellin in cotton fibers,and finally realize the regulation of cotton fiber development.Based on the above results,we speculate that GbSPL31 gene may play a role in the initiation and elongation of cotton fibers,which lays a foundation for the analysis of the development regulation mechanism of cotton fibers.