全长和缺失信号肽类似序列的HpaXm转基因烟草及其抗病性比较

he full-length HpaXm and the signal peptide like segment-deleted mutant HpaXm△LP from Xanthomonas citri subsp.malvacearum, were transferred into tobaccos (Nicotiana tobacum cv.Xanthi nc). with the method of Agrobacterium-mediated transformation. The resulting transgenic tobaccos were obtained by molecular identification and protein activity assay, to study the effect of the signal peptide like segment for the expression of HpaXm in transgenic tobaccos. Detection of the target gene and the 35S promoter sequences by PCR and the target genes sequences by PCR-Southern blot hybridization in genome from the T1 line positive transgenic plants, showed that the HpaXm gene and HpaXm△LP gene had already integrated into the recipient genomes respectively; reverse transcriptase PCR indicated that the transferred genes expressed normally. Soluble proteins extracted from plants transformed with HapXm and HpaXm△LP could stimulate hypersensitive response on tobacco leaves respectively, indicating that HapXm or HpaXm△LP expressed in transgenic tobacco plants are bioactive. Disease resistance bioassays showed that, the tobacco plants transformed with HpaXm gene enhanced resistance to TMV similarly as those transformed with HpaXm△LP gene. It suggests that the signal peptide like segment is no necessary for the endogenous expression and activity of hpaXm, and ability of hpaXm inducing tobacco resistance against TMV.?????