Problems Encountered with the Selection of Cucumber Mosaic Virus (CMV) Isolates for Resistance Breeding Programs
Problems Encountered with the Selection of Cucumber Mosaic Virus (CMV) Isolates for Resistance Breeding Programs
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DOI：
10.1111/j.1439-0434.2011.01816.x
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发表时间：
2011-09
影响因子：
1.5
通讯作者：
Deyong Zhang;X. Tan;P. Willingmann;G. Adam;C. Heinze
中科院分区：
文献类型：
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作者：
Deyong Zhang;X. Tan;P. Willingmann;G. Adam;C. Heinze
在亚洲蔬菜研究中心的辣椒育种系中，选择了两个用于筛选主要来自亚洲国家的更大选择的黄瓜花叶病毒（CMV）分离物。辣椒品系（VC 246）表现出对几个CMV分离物的抗性，并与辣椒品系VC 27 a，是敏感的CMV感染进行了比较。在28个CMV分离物中，5个分离物被鉴定为对VC 246系的抗性破坏（AN-样）和非抗性破坏（P3613-样），而所有分离物都可以建立对VC 27 a的系统感染。然而，进一步的测试表明，VC 246的抗性还取决于接种方式和接种物本身。嫁接接种可以克服抗性，用分离的病毒RNA接种抗病辣椒品系，结果是不受病毒分离物的影响。利用假重组的方法，我们鉴定了抗性破坏菌株的RNA 2作为系统感染的原因，并将RNA 2内的区域限制在3′端部分，包括ORF 2b。该区域的序列比对显示，在氨基酸水平上有8个不同的突变，这些突变存在于抗性或非抗性破坏菌株中。这些突变中的两个从P3613样序列到AN样序列的逆转对辣椒属物种没有诱导作用，但在几种烟草物种上诱导的症状与野生型病毒诱导的症状不同。然而，假重组体，每个从两个不同的AN样分离物，这是预期感染VC 246系统，没有表明可能RNA 2必须在一个特定的情况下有效果。在这种情况下，将功能普遍归因于单个氨基酸交换可能是不可能的，或者至少是极其困难的。
Among the Chili breeding lines from the Asian Vegetable Research Center, two were chosen for the screening of a larger selection of Cucumber mosaic virus (CMV) isolates, mainly from Asian countries. The chili line (VC246) showed a resistance against several CMV-isolates and was compared with chili line VC27a that was susceptible to CMV infection. Among the 28 CMV isolates, five were identified as resistance breaking (AN-like) and non-resistance breaking (P3613-like) for the line VC246, whereas all isolates could establish a systemic infection on VC27a. However, further testing revealed that resistance in VC246 was also dependent on the way of inoculation and the inoculums itself. Graft inoculation could overcome the resistance, and the inoculation with isolated viral RNA resulted in no infection at all on the resistant chili line, independent of the virus isolate. Using a pseudo-recombinant approach, we identified RNA2 of resistance breaking isolates as responsible for systemic infection and confined the area within RNA2 to the 3′ terminal part including the ORF 2b. Sequence alignments of that area revealed eight distinct mutations on amino acid level, which was present either in resistance or non-resistance breaking isolates. A reversion from the P3613-like to the AN-like sequence of two of these mutations induced no effect on Capsicum sp., but induced symptoms on several tobacco species distinct from those induced by the wild-type virus. However, pseudorecombinants, each generated from sets of two different AN-like isolates, which were expected to infect VC246 systemically, did not indicating that probably RNA2 must be in a specific context to have the effect. In this case, a generalized attribution of functions to single amino acid exchanges might be impossible or at least extremely difficult.