中文摘要：

从棉花角斑病菌（Xanthomonas citri subsp.malvacearum）中克隆并鉴定出的hpa Xm是一类新的harpin蛋白。笔者首次将来自棉花角斑病菌的hpa Xm基因采用农杆菌介导法导入模式生物三生烟（Nicotiana tobacum‘Xanthi nc.’）,获得转基因烟草,并通过分子鉴定和蛋白活性测定,研究hpa Xm的内源表达对转基因烟草的影响。结果表明：PCR扩增检测到T1代烟草阳性植株的靶基因序列及35S启动子序列,Southern blot检测结果证明hpa Xm基因已经整合到受体基因组中,RT-PCR结果显示在转录水平上正常表达。从转hpa Xm基因烟草中分别提取可溶性蛋白能激发烟草产生过敏反应,说明目的基因在转基因烟草中能表达出有活性的蛋白。hpa Xm的内源表达虽不能使转基因烟草产生大面积可见的坏死斑,但经台酚蓝染色后能观察到微过敏反应现象,同时hpa Xm能诱导转基因烟草对烟草花叶病毒（TMV）产生抗性。本研究对于探索hpa Xm在转基因作物中所诱导的生物学特性提供科学依据。

英文摘要：

HpaXm, cloned and identified from Xanthomonas citri subsp, malvacearum, is a new class of harpin proteins. Tobacco （ Nicotiana tobacum ＇ Xanthi nc＇ ） was transformed with HpaXm through Agrobacterium-mediation, and the resultant transgenic tobacco plants were subjected to molecular identification and protein activity assay to study the effect of the endogenous expression of hpaXm in the transgenic tobacco. The target gene and the 35S promoter sequences were detected by PCR, and the target genes sequences were detected by Southern Blot hybridization in the genome from the TI line positive transgenic plants, indicating that the hpaXm gene had already been integrated into the recipient genomes. Reverse transcriptase PCR indicated that the transferred genes were expressed normally in the transgenic plants. Soluble proteins extracted from plants which had been transformed with hpaXm could stimulate hypersensitive response on tobacco leaves, indicating that hpaXm ex- pressed in transgenic tobacco plants are bioactive. Although the endogenous expression of hpaXm failed to make a large area visible necrotic spots, but the phenomenon of micro-allergic reactions was observed after trypan blue staining. Constitutive expression of hpaXm in transgenic tobaccos conferred defense responses to TMV. The study would provide a scientific basis to explore the biological characteristics of transgenic plants induced by hpaXm.