Rispail N, Rubiales D
CSIC, Institute for Sustainable Agriculture, Alameda del Obispo s/n, Apdo. 4084, 14080 Córdoba, Spain.
Plant Dis. 2014 May;98(5):667-673. doi: 10.1094/PDIS-03-13-0217-RE.
The resistance of 267 Medicago truncatula accessions was determined against the soilborne pathogen Fusarium oxysporum, one of the major constraints of forage and grain legumes worldwide. The initial screening of the collection revealed a wide range of disease response from completely resistant to highly susceptible to one strain of F. oxysporum f. sp. medicaginis. As a result, 26 accessions were identified as resistant, 9 as susceptible, and all other accessions as partially resistant. The phenotype of 12 resistant accessions was confirmed in two independent experiments on a subset of 23 accessions. Quantification of F. oxysporum f. sp. medicaginis within plant tissue indicated that the resistance level of the accessions is correlated with the amount of F. oxysporum f. sp. medicaginis within its shoot. Inoculation with a different F. oxysporum f. sp. medicaginis isolate indicated that the resistance phenotype was stable because accession response to both F. oxysporum f. sp. medicaginis strains followed similar trends. However, grouping accessions according to their geographic origin did not reveal foci of resistance, which supports the idea that resistance arose from independent events. The identification of 12 resistant accessions will be useful for further cellular and molecular studies to unravel the basis of resistance to F. oxysporum in this model species and to transfer resistance to legume crop.
测定了267份蒺藜苜蓿种质对土传病原菌尖孢镰刀菌的抗性，尖孢镰刀菌是全球范围内饲草和豆类作物的主要限制因素之一。对该种质资源的初步筛选显示，对尖孢镰刀菌苜蓿专化型的一个菌株，其病害反应范围很广，从完全抗性到高度感病。结果，鉴定出26份种质为抗性，9份为感病，所有其他种质为部分抗性。在对23份种质的一个子集进行的两个独立实验中，证实了12份抗性种质的表型。对植物组织内尖孢镰刀菌苜蓿专化型的定量分析表明，种质的抗性水平与其地上部尖孢镰刀菌苜蓿专化型的数量相关。用不同的尖孢镰刀菌苜蓿专化型分离株接种表明，抗性表型是稳定的，因为种质对两种尖孢镰刀菌苜蓿专化型菌株的反应遵循相似的趋势。然而，根据地理起源对种质进行分组并没有揭示出抗性集中区域，这支持了抗性是由独立事件产生的观点。鉴定出的12份抗性种质将有助于进一步开展细胞和分子研究，以阐明该模式物种对尖孢镰刀菌的抗性基础，并将抗性转移到豆类作物中。
