转Cecropin B抗菌肽基因柑橘对溃疡病的离体抗性评价

本文对转Cecropin B抗菌肽基因的锦橙植株进行了表达检测以及柑橘溃疡病病原菌的接菌实验。分别用喷雾法和针刺法进行离体接菌实验，用Real-time PCR和Southern blot进一步检测分析了在转基因植株中Cecropin B基因的表达、整合情况。结果显示与喷雾法相比，针刺接种处理的离体叶片开始显症时间短，且发病率高，便于统计分析。针刺接种6天后，大部分转基因株系发病率与非转基因植株无显著差异，其中，PR8、PR11、AAT8 和AAT14株系的发病率分别为67%、63%、68%和54%，显著低于非转基因植株。Real-time PCR表达分析结果表明,转基因株系中Cecropin B基因表达量明显高于对照株系。Southern blot结果显示PR8和AAT14株系中转基因为单拷贝， PR11和AAT8株系中转基因分别为两个拷贝和三个拷贝。实验结果表明转Cecropin B抗菌肽基因提高了对柑橘溃疡病的抗性。

In vitro resistance of transgenic Jin-cheng orange (Citrus Sinensis Osb.) plants with Cecropin B gene to citrus canker caused by Xanthomonas axonopodis pv. Citri

Resistance of transgenic Jin-cheng plants with Cecropin B to Xanthomonas axonopodis pv. Citri (Xac) has been investigated through in vitro leaf inoculation tests. Pin-puncture and spray inoculations were used to resistance to citrus canker disease. Expression of Cecropin B gene in transgenic plants was analyzed by Real time q-PCR and Southern blotting. Inoculation with Xac suspensions on nontransgenic citrus leaves showed that visible lesions was detected in 80% leaves 3 days of inoculation using needle-puncture inoculation, while it was observed in only 10% leaves after 10 days of infection when using spray inoculation. The needle-puncture inoculation on transgenic leaves showed that four lines (PR8, PR11, AAT8and AAT14) had strong resistance to Xac compared with nontransgenic plants. Real time quantitative PCR indicated that Cecropin B was expressed in these lines. Southern blotting analysis showed that 1-3 copies of transgene were detected in these lines. Transgenic Jin-cheng with Cecropin B gene had gained increased resistance to Xac.