中国农业科学 ›› 2022, Vol. 55 ›› Issue (22): 4398-4407.doi: 10.3864/j.issn.0578-1752.2022.22.006

• 植物保护 • 上一篇    下一篇

基于柑橘叶斑驳病毒的表达载体构建及应用

张琦(),段玉(),苏越,蒋琪琪,王春庆,宾羽,宋震()   

  1. 西南大学柑桔研究所/国家柑桔工程技术研究中心,重庆 400712
  • 收稿日期:2022-07-04 接受日期:2022-07-16 出版日期:2022-11-16 发布日期:2022-12-14
  • 通讯作者: 宋震
  • 作者简介:张琦,E-mail:18839773525@163.com。|段玉,E-mail:982432080@qq.com
  • 基金资助:
    国家重点研发计划(2021YFD1400800);重庆市自然科学基金(CSTB2022NSCQ-MSX0752)

Construction and Application of Expression Vector Based on Citrus Leaf Blotch Virus

ZHANG Qi(),DUAN Yu(),SU Yue,JIANG QiQi,WANG ChunQing,BIN Yu,SONG Zhen()   

  1. Citrus Research Institute, Southwest University/National Citrus Engineering Research Center, Chongqing 400712
  • Received:2022-07-04 Accepted:2022-07-16 Online:2022-11-16 Published:2022-12-14
  • Contact: Zhen SONG

摘要:

【目的】 构建基于柑橘叶斑驳病毒(citrus leaf blotch virus,CLBV)的表达载体,通过系统表达抗菌肽提高植物抗病性,为柑橘溃疡病、柑橘黄龙病等病害的防控提供新型技术手段。【方法】 基于前期构建的侵染性克隆pCY-CLBV201,在外壳蛋白基因终止子后插入亚基因组启动子序列及多克隆位点,构建病毒表达载体pCLBV202。在多克隆位点插入绿色荧光蛋白(green fluorescent protein)基因(gfp),通过农杆菌介导接种、荧光观察验证pCLBV202-GFP表达GFP的情况。克隆天蚕的抗菌肽(cecropin B,CB)基因并构建重组载体pCLBV202-CB,通过农杆菌介导分别注射接种本氏烟和真空浸润接种柑橘实生苗,筛选阳性植株并分别注射接种和根灌接种烟草青枯病菌及针刺离体叶片接种柑橘溃疡病菌,同时设空载体接种植株为对照,通过症状观察、发病率及病情指数评价接种植株的烟草青枯病抗性;通过柑橘叶片的病斑数量、发病率及菌落浓度评价其溃疡病抗性。【结果】 pCLBV202-GFP接种烟草和尤力克柠檬后,均可以在系统新叶上观察到绿色荧光,在烟草上表现更为明亮,说明基于CLBV的表达载体构建成功。接种青枯病菌后,处理组(pCLBV202-CB)较对照组(pCLBV202)发病时间延迟4 d。在接种后第24天(24 dpi),处理组发病率为14.3%,对照组发病率为100%,差异显著。处理组相对于对照组的抗性指数为-2.66,抗性评价为高抗,表明利用pCLBV202-CB系统表达CB增强了对烟草青枯病的抗性。尤力克柠檬叶片针刺接种柑橘溃疡病菌,7 dpi时,处理组病斑数为47个,发病率为43.5%,对照组病斑个数为73个,发病率为67.6%。菌群数变化检测发现,处理组菌群数小于对照组菌群数,表明利用pCLBV202-CB系统表达CB增强了尤力克柠檬的溃疡病抗性。【结论】 构建了基于CLBV的病毒表达载体pCLBV202。利用pCLBV202在本氏烟和柑橘中系统表达CB可以提高植株对细菌性病害的抗性,这为柑橘细菌性病害的防控提供了新技术。

关键词: 柑橘叶斑驳病毒, 病毒表达载体, 抗菌肽, 抗病性

Abstract:

【Objective】 The objective of this study is to construct an expression vector based on citrus leaf blotch virus (CLBV) and systematically express antimicrobial peptides to improve plant disease resistance, which will provide a new technical means for the prevention and control of citrus canker, citrus Huanglongbing (HLB) and other diseases.【Method】The subgenomic promoter sequence and multiple cloning sites were inserted after the terminator of the coat protein gene of CLBV to construct the viral expression vector pCLBV202 based on the previously constructed infectious clone pCY-CLBV201. Then green fluorescent protein gene (gfp) was inserted into the multiple cloning sites, and the expression of GFP was verified by Agrobacterium-mediated inoculation and fluorescence observation. The cecropin B (CB) gene of Antheraea pernyi was cloned and the recombinant vector pCLBV202-CB was constructed. Nicotiana benthamiana and citrus seedlings were inoculated by pCLBV202-CB using Agrobacterium-mediated injection and vacuum infiltration, respectively. Positive plants were screened and subjected to inoculation of Ralstonia solanacearum by injection and root irrigation or Xanthomonas citri subsp. citri (Xcc) by pricking the detached leaves. At the same time, the plants inoculated with the empty vector were set as the control. The resistance to tobacco bacterial wilt of the inoculated plants was evaluated by symptom observation, incidence rate and disease index. The citrus resistance to canker was evaluated by the detriment, incidence rate and colony concentration on leaves. 【Result】After inoculated by pCLBV202-GFP, green fluorescence could be observed on the systemic leaves of the N. benthamiana and Citrus limon, which was brighter in N. benthamiana, indicating that the expression vector based on CLBV was successfully constructed. After inoculation of R. solanacearum, the onset time of treatment group (pCLBV202-CB) was delayed by 4 days compared with the control group (pCLBV202). On the 24th day past inoculation (24 dpi), the incidence rate of the treatment group was 14.3%, and that of the control group was 100%. Compared with the control group, the resistance index of the treatment group was -2.66, and the resistance evaluation was high, indicating that the expression of CB by pCLBV202-CB enhanced the resistance to tobacco bacterial wilt. When C. limon leaves was inoculated by Xcc, the number of detriment in the treatment group at 7 dpi was 47, and the incidence rate was 43.5%, while that of the control group was 73, and 67.6%. The detection of colony concentration changes of Xcc showed that the number of Xcc in the treatment group was less than that in the control group, indicating that the expression of CB by pCLBV202-CB enhanced the resistance to citrus canker.【Conclusion】 The CLBV-based viral expression vector pCLBV202 was constructed. Using pCLBV202 to systematically express CB in N. benthamiana and citrus can improve the resistance of plants to bacterial diseases, which provided a new technology for the prevention and control of citrus bacterial diseases.

Key words: citrus leaf blotch virus (CLBV), viral expression vector, antimicrobial peptide, disease resistance