Strategies for Citrus to Acquire Resistance to Canker Disease
Three strategies have been adopted to obtain resistance to canker disease. The first was screening resistant genotypes from the abundant germplasm in China, and another was stopping the pathogenesis of the pathogen by gene engineering. After a preliminary investigation in field, 7 accessions from Citrus ichangensis Swingle, 5 accessions from C. junos Sieb. ex Tanaka, and citron (C. medica L.)were chosen for screening by inoculating with the pathogen of Xanthomonas axonopodis pv. citri in vitro and in vivo. The in vitro assay indicated that 6 genotypes (3 in Ichang papeda, 2 in C. junos and citron) were resistant, but 2 years successive in vivo investigations indicated that citron was the only completely resistant genotype, without any typical canker symptoms on leaves. Since the pthA gene is essential for the pathogen to cause hyperplastic canker symptoms on citrus, the 2nd and 3rd strategies were focused on stopping the function of nuclear localizing signals (NLSs) in pthA. The sense and antisense NLSs were cloned and then transferred into sweet orange via Agrobacterium-mediated transformation to stop the pathogenicity of the pathogen. As a result, nine transgenic sense NLS were obtained and all of them demonstrated prominent resistance to citrus canker disease by in vitro inoculation test. The 3rd strategy was based on plant antibody technology. NLSs was cloned into PET32a(+)vector and the recombinant fusion protein was expressed in Escherichia coli BL21 (DE3 ). A 48 ku of recombinant fusion protein was purified and used to immunize Balb/c mouse to obtain antisrum. Three cell lines producing monoclonal antibody were then developed. The variable region gene (ScFv) of the monoclonal antibody was constructed and cloned into pBI121 plant expression vector. Agrobacteriummediated transformation was applied to introduce ScFv into sweet orange. Twelve transgenic plants were obtained and some of them were highly resistant by in vitro assay.
Canker disease In vitro inoculation In vivo assay PthA-NLS gene Monoclonal antibody ScFv gene
Z. N. Deng C. H. Hu L. Xu J. Y. Zhang L. Yang D. Z. Li N. Li L. P. Liu
Hunan Provincial Key Laboratory of Crop Germplasm Innovation and Utilization, Hunan Agricultural Uni National Centre for Citrus Improvement, Hunan Agricultural University,Changsha, Hunan 410128, P. R.
国际会议
11th International Citrus Congress(第11届国际柑橘大会)
武汉
英文
1035-1042
2008-10-01（万方平台首次上网日期，不代表论文的发表时间）