链格孢菌是一种机会性人类真菌病原体,是一种普遍存在的植物病原体,能够对>100种农作物和观赏植物引起疾病。为了控制由A引起的植物病害,三唑类杀真菌剂已广泛用于露地作物和蔬菜地以及室内生长设施如温室。目前,杀菌剂的使用对交替草种群中三唑抗性发展的影响尚不清楚。这里,我们从云南昆明大都市周围的9个温室中分离出237个交替菌株,中国西南,使用10个短串联重复标记确定它们的基因型,并量化了它们对四种三唑(苯醚甲环唑,戊唑醇,伊曲康唑,和伏立康唑)。在这些A.alternata菌株中检测到丰富的等位基因和基因型多样性。重要的是,超过17%的菌株对苯醚甲环唑耐药,在三唑靶基因cyp51中发现了已知和新的耐药突变。我们对温室中A.alternata的高水平遗传变异以及高频杀菌剂抗性的发现要求人们更加关注温室中的持续监测和开发替代植物真菌病管理策略。IMPORTANCEAlternariaalternata是我们环境中最常见的真菌之一,如室内设施,土壤,和室外空气。它可以在>100种作物和观赏植物中引起疾病。此外,它会导致人类感染。然而,我们对其遗传多样性和抗真菌易感性的理解非常有限。的确,对于该物种中的大多数抗真菌药物,耐药性的临界阈值尚未确定。已知温室具有农业杀真菌剂的大量应用。在这项研究中,我们分析了来自中国西南部昆明大都市附近9个温室的A.alternata菌株。我们的研究揭示了非常高的遗传多样性,并在9个温室中的每个温室中鉴定出对两种农业和两种医用三唑抗真菌剂具有高MIC值的菌株。我们的研究呼吁更加关注这种对粮食安全和人类健康的新威胁。
Alternaria alternata is an opportunistic human fungal pathogen and a ubiquitous phytopathogen capable of causing diseases to >100 agricultural crops and ornamental plants. To control plant diseases caused by A. alternata, triazole fungicides have been widely used both in open crop and vegetable fields and in indoor growth facilities such as greenhouses. At present, the effect of fungicide use on triazole resistance development in A. alternata populations is not known. Here, we isolated 237 A. alternata strains from nine greenhouses around metropolitan Kunming in Yunnan, southwest China, determined their genotypes using 10 short tandem repeat markers, and quantified their susceptibility to four triazoles (difenoconazole, tebuconazole, itraconazole, and voriconazole). Abundant allelic and genotypic diversities were detected among these A. alternata strains. Significantly, over 17% of the strains were resistant to difenoconazole, and both known and new drug-resistance mutations were found in the triazole target gene cyp51. Our findings of high-level genetic variation of A. alternata in greenhouses coupled with high-frequency fungicide resistance call for greater attention to continued monitoring and to developing alternative plant fungal disease management strategies in greenhouses. IMPORTANCE Alternaria alternata is among the most common fungi in our environments, such as indoor facilities, the soil, and outdoor air. It can cause diseases in >100 crop and ornamental plants. Furthermore, it can cause human infections. However, our understanding of its genetic diversity and antifungal susceptibility is very limited. Indeed, the critical threshold values for resistance have not been defined for most antifungal drugs in this species. Greenhouses are known to have heavy applications of agricultural fungicides. In this study, we analyzed strains of A. alternata from nine greenhouses near metropolitan Kunming in southwestern China. Our study revealed very high genetic diversity and identified strains with high MIC values against two agricultural and two medical triazole antifungals within each of the nine greenhouses. Our study calls for greater attention to this emerging threat to food security and human health.