Aphid resistance in Medicago truncatula involves antixenosis and phloem-specific, inducible antibiosis, and maps to a single locus flanked by NBS-LRR resistance gene analogs
Aphid resistance in Medicago truncatula involves antixenosis and phloem-specific, inducible antibiosis, and maps to a single locus flanked by NBS-LRR resistance gene analogs
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DOI：
10.1104/pp.104.051243
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发表时间：
2005-04-01
期刊：
影响因子：
7.4
通讯作者：
Singh, KB
中科院分区：
文献类型：
--
作者：
Klingler, J;Creasy, R;Singh, KB
蚜虫和相关昆虫以植物中的单一细胞类型为食：韧皮部筛元。摘要在短叶苜蓿中发现了对蓝绿蚜或蓝苜蓿蚜的遗传抗性。（桶状培养基）并回交成易感品种。作为一种模式豆科植物，我们可以在生理、生化和分子水平上深入研究对这种蚜虫的防御。在本研究中，两个密切相关的抗性和敏感基因型被用来表征蚜虫抗性表型。抗性条件是抗虫害，因为在释放后6小时内，迁徙蚜虫不会在抗性植物上定居，而更倾向于在易感植物上定居。摄食行为分析表明，该性状在韧皮部筛元水平上影响小野蓟。蚜虫在切除的嫩枝上繁殖表明，抗性需要完整的植株。先前的侵染增强了对小夜蛾的抗生素作用，表明诱导了这种韧皮部特异性防御。在两个定位群体中，抗性分离为一个单一的显性基因AKR（赤曲斑马鱼抗性），这被用于将位点定位到一个区域，该区域两侧是抗性基因类似物，预计编码抗性蛋白的CC-NBS-LRR亚家族。本研究为今后植物模式系统中韧皮部寄生防御的分子分析提供了基础。
Aphids and related insects feed from a single cell type in plants: the phloem sieve element. Genetic resistance to Acyrthosiphon kondoi Shinji (bluegreen aphid or blue alfalfa aphid) has been identified in Medicago truncatula Gaert. (barrel medic) and backcrossed into susceptible cultivars. The status of M. truncatula as a model legume allows an in-depth study of defense against this aphid at physiological, biochemical, and molecular levels. In this study, two closely related resistant and susceptible genotypes were used to characterize the aphid-resistance phenotype. Resistance conditions antixenosis since migratory aphids were deterred from settling on resistant plants within 6 h of release, preferring to settle on susceptible plants. Analysis of feeding behavior revealed the trait affects A. kondoi at the level of the phloem sieve element. Aphid reproduction on excised shoots demonstrated that resistance requires an intact plant. Antibiosis against A. kondoi is enhanced by prior infestation, indicating induction of this phloem-specific defense. Resistance segregates as a single dominant gene, AKR (Acyrthosiphon kondoi resistance), in two mapping populations, which have been used to map the locus to a region flanked by resistance gene analogs predicted to encode the CC-NBS-LRR subfamily of resistance proteins. This work provides the basis for future molecular analysis of defense against phloem parasitism in a plant model system.