杨树PagABP1介导生长素信号影响植株生长OA

[Objective]Through genome-wide identification and bioinformatics analysis of PagABP gene family of Populus alba×P.glandulosa,the gene PagABP1 that is highly expressed in young stems,cambium,xylem and phloem was selected to explore its effect on radial and height growth of this poplar.This study aims to provide a theoretical basis for elucidating how the auxin signaling pathway regulates secondary growth of stems by studying the regulatory role of this gene in the radial and height growth of poplars.[Method]Bioinformatics and related software were used to identify the members of the PagABP gene family in 84K poplar.The real-time fluorescence quantitative PCR was used to analyze the expression of PagABP1 gene in terminal buds,young leaves,young stems,young roots,mature stems,old roots,root tips,phloem,vascular cambium and xylem.Plant PPagABP1::GUS promoter vector and overexpressing 35S::PagABP1 vector were constructed by using the PagABP1 promoter and coding region sequences,respectively.Agrobacterium-mediated method was used to create 84K poplar transgenic materials that were used to identify the effects of PagABP1 gene on poplar radial and height growth.[Result]Two ABP homologous genes were identified in 84K poplar genome,and the PagABP1 gene showed relatively higher expression levels in the apical bud,young stems,phloem,cambium,and xylem.The expression locations of PPagABP1::GUS in transgenic poplar were overlapped with those of PpagDR5::GUS(auxin response reporter gene),mainly in the terminal bud,young stem,cambium,phloem,and primary xylem,suggesting that PagABP1 is involved in auxin-mediated regulation of radial and height growth.The germination number and growth rate of PagABP1-OE lines were significantly higher than those of the control when the truncated seedlings were planted in soil.Analysis of transgenic lines(#17、#26)that overexpressed PagABP1 gene at 60 days showed that the width of the cambium,primary xylem,and phloem of 12th internode,plant height and basal diameter increased by 50.2%,43.3%,1.58%,19.14%and 19.29%,respectively,compared to the control.[Conclusion]PagABP1 gene is associated with auxin expression site,mainly expressed in terminal buds,young stem,phloem,cambium,and primary xylem,affecting radial and height growth.This study can lay a foundation for further revealing the molecular mechanism of PagABP1 gene involved in stem growth of 84K poplar.