| Ethylene response factor is a transcription factor that plays an important role in the process of plant growth and development.Previous studies have shown that ERF110 gene can regulate the growth and development of Arabidopsis thaliana,but its related research in woody plants has not been reported.In this study,the biological function and mechanism of PtrERF110 gene in the growth,development and secondary growth of Populus trichocarpa were preliminarily explored by using techniques and methods of molecular biology,genetics and statistics.The results are as follows:(1)The full-length c DNA of PtrERF110 gene is 1374 bp,encoding 457 amino acids.The acidic hydrophilic expressed by it is located in the nucleus and has transcriptional selfactivation activity.The PtrERF110 protein contains a 51 amino acid long AP2 conserved domain consisting of one α-helix and three antiparallel β-sheets.Its transcriptional activation domains are located at both ends of the conserved domains of AP2.(2)The promoter region of the PtrERF110 gene contains secondary growth-related cisacting elements(Secondary wall MYB-responsive element,SMRE)and(Secondary wall NAC binding element,SNBE),growth and development-related cis-acting elements(TATC-box,AAGAA-motif,as-1,G-Box and W box).PtrERF110 gene was expressed in all tissues of Populus trichocarpa,among which the expression level was relatively high in secondary phloem,primary xylem and secondary xylem.The Ptr OBP1 transcription factor involved in regulating the formation of secondary cell wall of Populus trichocarpa can bind to the promoter of PtrERF110 gene,and PtrERF110 can specifically recognize the high-frequency cis-acting elements SMRE and SNBE in the promoter region of secondary growth-related genes.(3)The plant p BI121MCS-PtrERF110-GFP overexpression and p BI121MCS-PtrERF110-SRDX12-GFP inhibition expression vectors were constructed,and the genetic transformation of Populus trichocarpa was carried out by Agrobacterium-mediated method.The obtained transgenic lines were verified by PCR and q RT-PCR technology,and 8 overexpression lines and 7 inhibition expression lines were successfully obtained.The phenotype and characters of transgenic Populus trichocarpa were analyzed,and it was found that the adventitious root length,lateral root length,plant height,stem node diameter,stem node number,leaf length and leaf width of Populus trichocarpa overexpressing PtrERF110 gene were significantly lower than those of wild-type Populus trichocarpa.The growth vigor of the transgenic Populus trichocarpa overexpressing the PtrERF110 gene was weak.However,the phenotype of the transgenic Populus trichocarpa that inhibited the expression of PtrERF110 gene was the opposite,and the growth was more vigorous.Comparing the stem stained sections of transgenic and wild-type Populus trichocarpa,it was found that the xylem stained area of Populus trichocarpa overexpressing PtrERF110 gene was smaller,the xylem cell diameter and vessel diameter were significantly smaller than those of wild-type Populus trichocarpa,and no phloem cells were observed in the sections.The xylem and phloem cells of Populus trichocarpa,which inhibited the expression of PtrERF110 gene,increased significantly,the duct cells became larger,and the xylem staining area was larger.Taking the wild-type Populus trichocarpa as a control,q RT-PCR analysis was performed on some genes related to secondary growth in transgenic Populus trichocarpa.We found that the relative expression levels of lignin,cellulose and hemicellulose synthesis-related genes were significantly reduced in transgenic Populus trichocarpa overexpressing PtrERF110 gene.However,the relative expression levels of lignin,cellulose and hemicellulose synthesis-related genes did not change or were significantly increased in the transgenic Populus trichocarpa inhibiting the expression of PtrERF110 gene.In conclusion,PtrERF110 gene is involved in regulating the secondary growth process of Populus trichocarpa and inhibiting the growth and development of Populus trichocarpa. |
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