Gene Screening And Functional Verification Relate To The Branching Development In Narrow Crown Poplar

Branching development is a complex biological process influenced by various factors,including genetic factors, hormone regulation, environment, and nutrition. It has an important significance in plant morphology.In grasses such as rice and maize, tillering number and crop yield has a direct relationship.Branching development in wood plants affects their ecological benefits and impacts wood formation. This study focused on Populus×zhaiguanheibaiyang, it had the character of little branch and narrow crown. One hormone regulation network was constructed, which provides clues for understanding the mechanism of hormones regulations.We analysed the different expression genes from the NC and BC. We analysed the expression pattern of the different expression genes and hormone regulation network form activated buds.We also cloned D14 α, β-hydrolase-the key gene of Strigolactones signaling and PIN1 gene-the key gene of auxin polar transport stream. Our research provide the foundation for the further study of woody plant branching development gene function and its mechanism in hormone regulation. The main results are as follows:1. A total of 198.2 million high-quality reads were generated from the four cDNA libraries, constituting 24.99 Gb of cDNA sequences.The reads in each library were mapped to the P. trichocarpa reference genome using BLAST, and 112.9 million reads(56.96%) were found to match locations in the 480-Mb reference genome; 105.7 million reads(53.3%)matched only one location.2. To assign biological functions and identify genes related to branching development,we used all the DEG sequences in BLASTX searches against the NCBI non-redundant(Nr)protein sequence database, Kyoto Encyclopedia of Genes and Genomes(KEGG), Clusters of Orthologous Groups(COG), Gene Ontology(GO), and Swiss-Prot. 3353 DEGs were annotated with Nr. 2805 DEGs were annotated withGo. 1389 DEGs were annotated with COG. 520 DEGs were associated with 101 KEGG pathways and were annotated with the corresponding Enzyme Commission(EC) numbers. The KEGG pathways related to hormoneregulation were plant hormone signal transduction(ko04075)(26, 5.00%), followed by tryptophan metabolism(ko00500)(8, 1.54%), and ABC transport(ko02010)(1, 0.19%).3. We found the gene involved in response to auxin, hormone-mediated signaling pathway, response to hormone, auxin-activated signaling pathway, auxin polar transport, and auxin biosynthetic process. One hormone regulation network was constructed, which provides clues for understanding the mechanism of hormones regulations. Many key differentially expressed genes were annotated, which promotes our understanding of the mechanism of hormones regulation in poplar branching development.4. 11 genes participant in branching development have been tested by real-time quantitative PCR and the result shows that 10 of the 11 genes have same trend with the expressing profile.5. We have cloned the gene D14 α, β-hydrolase-the key gene of Strigolactones signaling and PIN1 gene- the key gene of auxin polar transport stream. The gene PopD14 is 1169 bp,ORF is 1122 bp long, encoding 374 amino acids, it is homologous with Jatropha curcas,Ricinus communis;PopPIN1 is 1920 bp long, and ORF is 1860 bp long, encoding 620 amino acids, it is homologous with Jatropha curcas, Ricinus communis.