Screening and characterization of resistance to succinate dehydrogenase inhibitors in Alternaria solani
Screening and characterization of resistance to succinate dehydrogenase inhibitors in Alternaria solani
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DOI：
10.1111/ppa.12077
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发表时间：
2014-02-01
期刊：
影响因子：
2.7
通讯作者：
Wharton, P. S.
中科院分区：
文献类型：
--
作者：
Miles, T. D.;Miles, L. A.;Wharton, P. S.
在离体条件下测定了引起美国爱达荷州马铃薯早疫病的早疫病链格孢菌（Alternaria solani）对3种杀菌剂啶酰菌胺、氟吡菌酰胺和吡噻菌胺的敏感性。2009年从叶片感染组织中收集了20个菌株，2010年收集了26个菌株，2011年收集了49个菌株。采用螺旋梯度终点稀释法测定杀菌剂敏感性。在本研究期间，啶酰菌胺耐药菌株的频率（当使用从507 mgL（-1）开始的螺旋稀释梯度时，相对生长>50%）急剧增加（2009年为15%，2010年为62%，2011年为80%）。观察到对氟吡菌酰胺和吡噻菌胺的抗性增加。然而，仅观察到啶酰菌胺和吡噻菌胺之间的交叉抗性。这类杀真菌剂的目标位点是琥珀酸脱氢酶（SDH）酶复合物，这对真菌呼吸至关重要。SDH复合物的序列分析揭示了亚基B和D的突变，这些突变与爱达荷州马铃薯田出现啶酰菌胺抗性相关。特别地，分别在SDH亚基B和D中鉴定出H277 R和H133 R。基因序列中限制性位点的存在允许开发快速PCR-RFLP方法来评估立枯丝核菌种群中啶酰菌胺的敏感性。
Field isolates of Alternaria solani, which causes early blight of potato in Idaho, USA were evaluated in vitro for their sensitivity towards the succinate dehydrogenase inhibitor (SDHI) fungicides boscalid, fluopyram and penthiopyrad. A total of 20 isolates were collected from foliar-infected tissue in 2009, 26 in 2010 and 49 in 2011. Fungicide sensitivity was tested using the spiral-gradient end point dilution method. The frequency of boscalid-resistant isolates (>50% relative growth when using a spiral dilution gradient starting at 507mgL(-1)) drastically increased over the duration of this study (15% in 2009, 62% in 2010 and 80% in 2011). Increasing resistance to fluopyram and penthiopyrad was observed. However, cross-resistance was only observed between boscalid and penthiopyrad. The target site of this fungicide class is the succinate dehydrogenase (SDH) enzyme complex, which is vital for fungal respiration. Sequence analysis of the SDH complex revealed mutations in the subunits B and D that were correlated with the emergence of boscalid resistance in potato fields in Idaho. In particular, H277R and H133R were identified in SDH subunits B and D, respectively. The presence of restriction sites in the gene sequences allowed the development of a rapid PCR-RFLP method to assess boscalid sensitivity in A.solani populations.