Research On Branch Angle Genes PopTAC And PopLAXY In Narrow Crown Poplar

Trees are capable of tremendous architectural plasticity, allowing them to maximize their light exposure under highly competitive environments. One key component of tree architecture is the branch angle, yet little is known about the molecular basis for the spatial patterning of branches in trees. Here, ‘Populus leucopyramidalis 1’ and‘Populus×zhaiguanheiyang 11’ were used as experimental materials, The Pop TAC and Pop LAXY were cloned. We cloned Pro TAC and Pro LAXY promoters from‘Populus×zhaiguanheiyang 11’, 35S::Pop TAC,35S::Pop LAXY,Pro TAC::GUS and Pro LAXY::GUS expression vectors were constructed, The four expression vectors were transformed into Populus × euramiricana ‘Neva’ for further research and analysis. The major findings are described as followings:1.Two full-length c DNAs designated as Pop TAC and Pop LAXY gene were cloned from leaf of‘Populus leucopyramidalis 1’and xylem of ‘Narrow-crown poplar Aigeiros 11’.The open reading frame of Pop TAC was 807 bp and encoding 269 amino acids.The open reading frame of Pop LAXY was 1173 bp and encoding 391 amino acids.2.The ‘Populus×zhaiguanheiyang 11 ’and ‘Populus deltoides zhonglin 2025’ were studied in this paper. Gene expression profiles of Pop TAC and Pop LAXY genes in leaves、stem、axillary bud and roots of ‘Populus×zhaiguanheiyang 11 ‘and‘ Populus deltoides ‘zhonglin’2025’were monitored by q RT- PCR. q RT-PCR expression analysis showed that the expressions of Pop TAC gene in ‘Populus×zhaiguanheiyang 11 ‘ was Leaf> stem> axillary bud, there no expression in the root;The expressions of Pop TAC in ‘ Populus deltoides‘zhonglin’ 2025’ was stem >leaf > root >axillary bud. q RT-PCR expression analysis showed that the expressions of Pop LAXY gene in ‘Populus×zhaiguanheiyang 11 ‘ was stem> axillary bud >, Almost no expression in the leaf and root;The expressions of Pop LAXY in ‘Populus deltoides ‘zhonglin’ 2025’ was stem > axillary bud, Almost no expression in the Leaf and root.3. 35S::Pop TAC and 35S::Pop LAXY expression vectors were constructed, The two expression vectors were transformed into Populus × euramiricana ‘Neva’ via the Agrobactria-mediated leaf-disc transformation method.Three transgenic poplar plants of Pop TAC were screened out by genomic PCR and q RT-PCR. The expression of positive transgenic plants were 1960-fold higher、209-fold higher、19-fold higher respectively than in ck. One positive transgenic plant of Pop LAXY was found, and the expression of Pop LAXY was 31-fold higher than in ck.4..In the present study, we cloned Pro TAC and Pro LAXY promoters from ‘Narrow-crown poplar Aigeiros 11’ genomic DNA with the length at 1245 bp and 1214 bp respectively.5.Constructed plant transformation vectors using the β-glucuronidase(GUS) reporter gene system and detected the expression patterns of Pop TAC and Pop LAXY promoter in transgenic poplars Popu Lus × euramiricana ‘Neva’. Histochemical GUS assay showed GUS activity driven by Pop LAXY promoter in leaves vein and Pop TAC expression in leaf margin. The expression of Pro TAC and Pro LAXY in different tissues,such as, xylem of stems, petioles and veins of leaves needs further testing.