Studies On Three Stages Of Lateral Buds Of Plus Tree Clones In Populus Yunnanensis By CDNA-AFLP Markers

The plus trees of Populus yunnanensis collected from Sichuan and Yunnanprovince were used as experimental material, and cDNA-AFLP molecular technique wasconducted to examine expressing genes diversity at defoliation stage of lateral buds of54three-year seedlings, and at dormancy and sprouting stages of lateral buds of59three-yearseedlings of plus trees clones in P. yunnanensis. Furthermore, the transcript-derived fragmentswere cloned and the sequences were blasted in GeneBank. The main results were as followed:1. The results of research on lateral buds at defoliation stage of54three-year seedlings of plustree clones in P. yunnanensis by cDNA-AFLP marker(1) Using selected7primer combinations, a total of595bands were amplified, of which363(61.01%) were differential fragments, which indicated that the expressing genes in lateralbuds were plentiful among the individuals of plus trees at defoliation stage.(2) Overall genetic diversity HT=0.1053, average genetic diversity among differentpopulations HS=0.1025, coefficient of gene differentiation GST=0.0265, gene flow Nm=18.40meant that differences among individuals within same population were the main source of theexpressing genes.(3) The percentage of polymorphism (P), the Nei’s index (H), effective alleles (Ne) andShannon’s informative index (I) of Sichuan population was higher than these index in Yunnanpopulstion, which meant that the the expressing genes diversity of Sichuan population wasmore abundant than Yunnan population.(4) The average genetic similarity coefficient was0.8273, the highest genetic similaritycoefficient was between LBB001and LBB002(0.8824), which shared the closest geneticrelationship. The similarity coefficient between QXB006and LMM001was0.7529, they helda farthest genetic relationship.(5) The result of UPGMA cluster analysis showed that52individuals of P. yunnanensiswere clustered into the same group, so they had the closest genetic relationship.2. The results of research on lateral buds at dormancy stage of59three-year seedlings of plustree clones in P. yunnanensis by cDNA-AFLP marker(1) Using selected7primer combinations, a total of608bands were amplified, of which353(58.06%) were differential fragments, which indicated that lateral buds were rich inexpressing genes at dormancy stage.(2) Overall genetic diversity HT=0.1062, average genetic diversity among differentpopulations HS=0.1048, coefficient of gene differentiation GST=0.0123, gene flow Nm=40.28indicated that more expressing genes differences existed in different individuals within population than among different populations.(3) The Nei’s index (H) and Shannon’s informative index (I) of Yunnan population wasslightly higher than the index of Sichuan population, which meant that the expressing genesdifferences of Yunnan population was more abundant than that of Sichuan population.(4) The average genetic similarity coefficient was0.8263, and the highest geneticsimilarity coefficient was between QXJ031and LBB002, which two plus trees shared theclosest genetic relationship. The lowest similarity coefficient was between QXJ018andLMB034, which two plus trees had the farthest genetic relationship.(5) The result of UPGMA cluster analysis showed that52P. yunnanensis individuals ofwhole were clustered into the same group, so they had the closest relationship.3. The results of research on lateral buds at sprouting stage of59three-year seedlings of plustree clones in P. yunnanensis by cDNA-AFLP marker(1) Using selected7primer combinations, a total of577bands were amplified, of which318(55.11%) were differential fragments, which indicated that the expressing genes in lateralbuds were abundant at sprouting stage.(2) Overall genetic diversity HT=0.0954, average genetic diversity among differentpopulations HS=0.0938, coefficient of gene differentiation GST=0.0167, gene flow Nm=29.42.(3) The percentage of polymorphism (P), the Nei’s index (H), effective alleles (Ne) andShannon’s informative index (I) of Sichuan population was higher than Yunnan population.(4) The average genetic similarity coefficient was0.840, the highest genetic similaritycoefficient was between QXJ016and QXJ018, which shared the closest genetic relationship.The lowest similarity coefficient was between LMB029and LMB033, and between LMB028and LMB034, they held the farthest genetic relationships.(5) The clustering results showed that the mostly clones held the same branchingcharacteristics fell into subcluster unit or single cluster unit, which indicated thatcDNA-AFLP technique used to map, isolate and identify the candidate genes being related tobranching was feasible at sprouting stage.4. Analysis of transcript-derived fragments14transcript-derived fragments (TDFs) were obtained from three stages of lateral buds.Bioinformatics analysis showed that all14TDFs were homologous to the genes in P.trichocarpa, but only2TDFs were homologous to the transcription factors of AP2/ERF.