Genetic analysis and mapping of resistance to lettuce dieback: a soilborne disease caused by tombusviruses
Genetic analysis and mapping of resistance to lettuce dieback: a soilborne disease caused by tombusviruses
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DOI：
10.1007/s00122-004-1825-3
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发表时间：
2005-01-01
影响因子：
5.4
通讯作者：
Ryder, EJ
中科院分区：
文献类型：
--
作者：
Grube, RC;Wintermantel, WM;Ryder, EJ
现代，传家宝和专业品种，植物引进（PI）的加入，和生菜育种系的多样性收集筛选的敏感性生菜顶枯病，这是一种由土传病毒的家庭Tombusviridae引起的疾病。在以前被证明感染了莱切坏死矮化病毒的田地中，通过视觉症状评估来评价易感性。在多个田间试验中测试的241个基因型中，76个在受侵染的田间保持无虫害，因此被分类为抗顶枯。总体而言，抗性基因型在现代品种中与在传家宝品种或原始种质中一样普遍。然而，在现代种质，所有的脆头（冰山）品种是耐药的，而所有的长叶莴苣品种是易感的。利用酶联免疫吸附试验，在一些植物的抗性基因型，在受感染的领域，这表明，无病毒的植物是不能免疫病毒感染的叶片中检测到tombusviruses。本文研究了现代卷心莴苣品种Salinas和新育成的抗莴苣枯梢病种质PI 491224的抗性遗传。抗性由两种基因型中单一位点的显性等位基因赋予。从'Salinas'，Tvr 1，番茄丛矮病毒抗性基因座，映射在种内莴苣种群的位置，对应于连锁群2的莴苣的共识地图。莴苣抗性基因的最大簇，Dm 1/Dm 3簇，被发现在这个连锁群，然而，Tvr 1相对于这个簇的精确位置尚未确定。据我们所知，Tvr 1是第一个在植物宿主中发现的番茄丛矮病毒抗性基因。
A diverse collection of modern, heirloom and specialty cultivars, plant introduction (PI) accessions, and breeding lines of lettuce were screened for susceptibility to lettuce dieback, which is a disease caused by soilborne viruses of the family Tombusviridae. Susceptibility was evaluated by visual symptom assessment in fields that had been previously shown to be infested with Lettuce necrotic stunt virus. Of the 241 genotypes tested in multiple field experiments, 76 remained symptom-free in infested fields and were therefore classified as resistant to dieback. Overall, resistant genotypes were as prevalent among modern cultivars as in heirloom cultivars or primitive germplasm. Within modern germplasm, however, all crisphead (iceberg) cultivars were resistant, while all romaine cultivars were susceptible. Using enzyme-linked immunosorbent assay, tombusviruses were detected in leaves of some plants of resistant genotypes that were grown in infested fields, suggesting that symptom-free plants are not immune to viral infection. The inheritance of resistance was studied for 'Salinas', a modern iceberg cultivar, and PI 491224, the progenitor of recently released romaine germplasm with resistance to lettuce dieback. Resistance was conferred by a dominant allele at a single locus in both genotypes. The tombusvirus resistance locus from 'Salinas', Tvr1, was mapped in an intraspecific Lactuca sativa population to a location that corresponds to linkage group 2 on the consensus map of Lactuca. The largest cluster of resistance genes in lettuce, the Dm1/Dm3 cluster, is found on this linkage group; however, the precise position of Tvr1 relative to this cluster has not yet been determined. To our knowledge, Tvr1 is the first tombusvirus resistance gene identified for any plant host.