Analysis Of Biology Function Of PtrGATA12 During Secondary Growth Populus Trichocarpa

GATA transcription factor is a kind of transcription factor widely existing in eukaryotes,which plays an important role in plant light response regulation,cytokinin response,carbon and nitrogen metabolism and other biological processes,which are closely related to secondary growth.GATA12 is a member of GATA family,which has a direct or indirect influence on the regulation of plant secondary growth.At present,the gene of GATA family is only limited to the bioinformatics analysis of the GATA family,and the research on the biological function and regulation of GATA 12 gene in GATA family has not been carried out yet.Therefore,the biological function and regulation of secondary growth of GATA12 gene were systematically studied in this paper.The main conclusions are as follows:1.In this paper,the full-length cDNA sequence of Arabidopsis GATA12 ortholog gene PtrGATA12 was cloned from Populus trichocarpa,which is similar to PtrGATA18.1 and PtrGATAT.1 in the GATA family of Populus trichocarpa and named it as 86%.PtrGATA12 encodes 373 amino acids,has a molecular weight of 41397.57,an isoelectric point(PI)of 6.04,and has a typical domain of GATA family transcription factors at 260-310 amino acids:the presence of CX2CX18CX2C.2.Agrobacterium-mediated Seven overexpression.PtrGATA12 transgenic Populus trichocarpa strains were obtained.The phenotypes of the three lines with the highest GATA12 expression were continuously observed.The results showed that the transgenic lines had normal growth,but at 90 days of growth,the average plant height of PtrGATA12 transgenic papaya was 44.75 cm,and the base stem was 6.17 mm thick,which was 29.6%and 19.8%more than the wild type.During the whole phenotypic observation period,there was no significant difference in leaf size at each developmental stage compared with the control.3.Histochemical staining of PtrGATA12 overexpressing Populus trichocarpa secondary stems grown for 90 days showed that the stained area of lignin and hemicellulose became significantly wider;but,the stained area of cellulose did not change significantly.The content of the main components of the secondary cell wall was determined.Compared with WT,PtrGATA12-OE increased the lignin content by 8.4%and the hemicellulose content by 11.5%,and there was no significant change in cellulose content.At the same time,the measurement of fiber properties showed that the average length of PtrGATA12-OE fiber increased by 5.3%,the average fiber width decreased by 20.4%,and the thickness of SCW in stem tissue increased by 31.83%.4.Analysis of the expression levels of PtrGATA12 overexpressing Populus trichocarpa secondary growth-related genes showed that the lignin synthesis-related genes PtrCCOAOMT,PtrCOMT,PtrCCR1,PtrPAL1,PtrF5H,PtrCAD4,PtrCAD6,PtrHCT,PtrCCR2,and PtrPAL2 expression were significantly increased;the cellulose synthesis-related genes PtrCesA4 were significantly increased,PtrCesA 7,PtrCesA8,and PtrCOBL4 did not change significantly;the expression of PtrFRA8,PtrIRX8,PtrIRX9,PtrIRX14,and PtrIRX15 genes related to hemicellulose synthesis all increased;the expressions of fiber length and width related genes PtrSCPL49 increased,and the relative expressions of PtrEXPANSIN and PtrSCPL45 decreased;The programmed death genes PtrXCP1 and PtrXCP2 were down-regulated,and PtrRNS3 and PtrASP1 were up-regulated.5.The phenotype and secondary traits of the gata12 mutant of Arabidopsis thaliana showed that the average plant height of the gata12 mutant was 30.19 cm,and the base stem thickness was 1.38 mm,which was 24.67%and 11.76%lower than that of the wild type,respectively.Lignin deposition was significantly reduced,but There was no significant difference between cellulose and hemicellulose.There was no significant change in fiber length,but fiber width decreased by 22.96%;SCW thickness decreased by 28.62%.Simultaneously,fluorescent quantitative PCR results showed that lignin-related genes COMT,CCR1,CAD4,CAD6,C3H1,HCT,CCR2 and PAL2 expression in mutants were significantly reduced;the expression of CesA4 and CesA7 related to cellulose synthesis increased,the expression of CesA8 decreased;the expression of FRA8 and IRX8 related to hemicellulose synthesis increased.The expression of IRX9 decreased;the expression of genes related to cell swelling XTH5,SCPL45 and SCPL49 decreased;the expression of programmed death-related genes XND1 and XCP1 decreased,and the expression of LBD30 and XCP2 increased.The above results indicate that the GATA12 gene can regulate the growth of the stem of the plant to a certain extent,and can positively regulate the thickening of SCW.