Crop production and Pest Control Research Unit, ARS, USDA and Botany and Plant Pathology Department, Purdue University, West Lafayette, IN, USA.
School of Integrative Plant Science, Cornell University, Ithaca, NY, USA.
Virus Res. 2019 Oct 2;271:197674. doi: 10.1016/j.virusres.2019.197674. Epub 2019 Jul 23.
Phytophthora infestans is the causal agent of potato and tomato late blight. This pathogen, which caused the Irish potato famine, is of profound historical significance and still poses a major threat in today's agroecosystems. Research on late blight epidemics usually focuses on pathogen virulence, host resistance, environmental factors and fungicide resistance. In this study, we examined the effect of PiRV-2, an RNA virus harbored by some P. infestans isolates, on its host. Comparing isogenic isolates with or without the virus demonstrated that the virus stimulated sporangia production in P. infestans. Transcriptome analysis suggested that it achieved sporulation stimulation likely through down-regulation of ammonium and amino acid intake in P. infestans. Survey of a limited P. infestans collection found PiRV-2 presence in most strains in the US-8 lineage, a very successful clonal lineage of P. infestans in North America. We suggest that PiRV-2 may affect the ecological fitness of P. infestans and thus could contribute to late blight epidemiology.
马铃薯晚疫病菌是马铃薯和番茄晚疫病的致病菌。这种病原体曾引发爱尔兰马铃薯饥荒，具有深远的历史意义，至今仍对当今的农业生态系统构成重大威胁。晚疫病的研究通常集中在病原体的毒性、宿主的抗性、环境因素和杀菌剂抗性上。在这项研究中，我们研究了 RNA 病毒 PiRV-2 对其宿主的影响。比较有无该病毒的同基因分离株表明，该病毒刺激了晚疫病菌的游动孢子产生。转录组分析表明，它通过下调晚疫病菌对铵和氨基酸的摄取来实现孢子刺激。对有限的晚疫病菌分离物的调查发现，在美国 8 谱系中，PiRV-2 存在于大多数菌株中，这是北美的一个非常成功的晚疫病菌无性系。我们认为 PiRV-2 可能会影响晚疫病菌的生态适应性，从而可能影响晚疫病的流行病学。
