Phylogeny Analysis Of PMEs Gene Family And Function Of GhJAZ In Cotton

Cotton(Gossypium spp.) is the most important nat?ral ?ber plant in the world, is a primary source of raw materials of textile industry. The improvement of cotton fiber quality is becoming increasingly important, especially for higher intensity fiber. Improve the quality of cotton fiber is becoming increasingly important and is now a main focal point of cotton research. Cotton fiber development is delineated into four distinct and overlapping developmental stages: fiber initiation, elongation, secondary wall biosynthesis and maturation. Fiber initiation and elongation influence the number and length of the fiber while the secondary wall thickening impact of fiber strength, and a series of fiber quality traits. Previous studies showed that pectin methylesterase(PME, EC 3.1.1.11) play an important role in the process of fiber development.Pectin is an important component of the plant cell wall, which forms the main structural component of cotton fiber and pectin metabolism may influence fiber quality. In this study, cotton genome information was used to identify PMEs. The PMEs belong to a relatively conserved family in plant evolution. This study systematicly analysed the PMEs gene family memebers in cotton for the first time. Gossypium arboreum L.(Shixiya 1) and Gossypium hirsutum L.(69307) were selected as the material for the PMEs gene family fluorescence quantitative detection. According to the differential expression levels of PMEs family members at different developmental stages of cotton fiber, we analysed the function of PME gene.The main research results are as follows:PMEs gene family members were systematicly analysed in cotton genome A?D and AD. Based on cotton genome database of A genome ?D genome and AD genome, 293 PMEs family genes, incl?ding 135 in genome AD?80 in genome A and 78 in genome D, were identified with the bioinformatics method.The evolution of PMEs gene family was analysed. We identified 80(Ga PME01-Ga PME80) PMEs from diploid G. arboreum L.(A genome), 78(Gr PME01-Gr PME78) PMEs from G. raimondii(D genome),and 135(Gh PME001-Gh PME135) PMEs from tetraploid cotton G. hirsutum L.(AD genome), then divided them into 4 subfamilies, 4 subfamilies and 8 subfamilies according to gather relationship, respectivelye, we further analyzed their gene structures, conserved domains, gene expression patterns, three-dimensional structure and systematic evolution to lay the foundation for further research on the function of PMEs.Phylogenetic analysis indicated that genes from the same species showed high sequence similarities andrelatively close genetic relationships. Gene structural analysis indicated that most of the PMEs had 2-3exons, with a few having a variable number(4-6) of exons. There are nearly no differences among the three(two diploid cotton and a tetraploid cotton) cotton species. Conserved domain analysis shows that PMEs members have a relatively conserved C-terminal domain of Pectinesterase(PME) while the N-terminus is less stringent in the evolutionary process. Moreover, some of the family members contain pectin methylesterase inhibitor(PMEI) domain, which can provide an vital bases for the further study of PME gene family in cotton.qRT-PCR results showed that the subgroup I of Ga PMEs gene family members presented differential expression during different fiber development periods(10d, 15 d, 20 d, 25 d, 30d) The expression level of 16 genes was significantly upregulated in fiber secondary wall thickening stage, presence of tissue specificity.Transcriptome analysis of PME gene family demonstrated that among them, four genes assumed quite different expressed patternsbetween upland cotton and Asia in cotton fiber secondary wall thickening. To determine the mechanism underlying the differences, expression levels, gene structure, protein domain conservation, and sequence motifs were analyzed. The results explained that orthologous gene pairs show no significant different on their gene structure, conserved domain and motif. However, the promoter regions are changed.Selective pressure analysis showed that the Ka/Ks value for each of the three cotton species PME families was less than one. The Ka/Ks ratios suggest that the duplicated PMEs underwent purifying selection after the duplication events.Phenotype analysis of transantic Gh PME36 Arabidopsis plant. In this study, gene Gh PME36 was cloned, p BI121-Gh PME36 over-expression vector was constructed and was transformed into Arabidopsis thaliana col-0 by the pollen-tube pathway. The leaves of all transgenic plants were with different degrees of longer and wider than those of the wild type; Compared with wild type plants, the flowering period in the transgenic lines was postponed about 7 days. The average root length of the transgenic lines was longer than that of the wild type at the same time period.Phenotype analysis of transantic Gh JAZ Arabidopsis plant. Compared with wild type plants, the flowering period in the transgenic lines was advanced about 7 days. The average root length of the transgenic lines was longer than that of the wild type at the same time period. The capsule of all transgenic plants were with different degrees of shorter and thicker than those of the wild type. The trichomes ofArabidopsis appear relatively late, but the final number of the trichomes is consistent with the WT in the mature leaves.The study analysed the PMEs gene family members, the differential expression of PMEs in cotton and tested the phenotype of transgenetic Arabidopsis, laying foundation for further research about how does PME impact cotton fiber development and additional functions they may possess.