秋石斛不同外植体对MSO的敏感性及发根农杆菌转化效率比较OA

Phalaenopsis-type Dendrobium hybrids(Den-Phals)are important tropical ornamental plants,and establish-ing an efficient and stable genetic transformation system is crucial for gene functional research and molecular breeding.This study aimed to optimize selection conditions for genetic transformation and evaluate the transformation efficiency of different Agrobacterium rhizogenes strains.Using D.Noble Woman and D.Sonia Hiasakul as materials,the effects of different concentrations of L-methionine sulfoximine(MSO)on the growth of embryogenic calli(ECs),protocorms,calli and protocorm-like bodies(PLBs)were tested to determine optimal selection concentrations.The transformation efficiencies of three A.rhizogenes strains(K599,ATCC 15834,and MSU440)on four explant types of both cultivars were compared and verified through GUS staining and bar gene PCR detection.Results showed significant differences in MSO sensitivity among different explants.The complete lethal concentration for Noble Woman ECs and protocorms was 20 μmol/L and 15 μmol/L,respectively,and that for Sonia Hiasakul PLBs and callus tissues was 8 μmol/L and 10 μmol/L,respectively.The optimized selection pressure effectively reduced false positive rates.Regarding transfor-mation efficiency,strains ATCC15834 and MSU440 showed significantly higher transformation efficiency than K599 on most explants,with ATCC15834 achieving 7.45%positive rate for Noble Woman ECs and MSU440 reaching 8.42%for Sonia Hiasakul callus tissues.This study clarified applicable MSO concentrations for different explants of two Den-Phals and identified ATCC15834 and MSU440 as suitable A.rhizogenes strains for Den-Phals transformation,pro-viding technical references for further optimization of genetic transformation systems and molecular breeding applica-tions.