Schachterle Jeffrey K, Onsay Daphne M, Sundin George W
Genetics Graduate Program, Michigan State University, East Lansing, MI, United States.
Department of Plant, Soil, and Microbial Sciences, Michigan State University, East Lansing, MI, United States.
Front Microbiol. 2019 Nov 29;10:2775. doi: 10.3389/fmicb.2019.02775. eCollection 2019.
, causative agent of fire blight disease of apple and pear trees, has evolved to use small RNAs for post-transcriptional regulation of virulence traits important for disease development. The sRNA ArcZ regulates several virulence traits, and to better understand its roles, we conducted a transcriptomic comparison of wild-type and Δ mutant . We found that ArcZ regulates multiple cellular processes including genes encoding enzymes involved in mitigating the threat of reactive oxygen species (, , ), and that the Δ mutant has reduced catalase activity and is more susceptible to exogenous hydrogen peroxide. We quantified hydrogen peroxide production by apple leaves inoculated with and found that the while wild-type cells produce enough catalase to cope with defense peroxide, the Δ mutant is likely limited in virulence because of inability to cope with peroxide levels in host leaves. We further found that the ArcZ regulon overlaps significantly with the regulons of transcription factors involved in oxidative sensing including Fnr and ArcA. In addition, we show that ArcZ regulates at the post-transcriptional level suggesting a role for this system in mediating adaptations to oxidative state, especially during disease development.
苹果和梨树火疫病的病原体，已经进化出利用小RNA对疾病发展重要的毒力性状进行转录后调控。小RNA ArcZ调控多种毒力性状，为了更好地理解其作用，我们对野生型和Δ突变体进行了转录组比较。我们发现ArcZ调控多个细胞过程，包括编码参与减轻活性氧（，，）威胁的酶的基因，并且Δ突变体的过氧化氢酶活性降低，对外源过氧化氢更敏感。我们对接种了的苹果叶片的过氧化氢产生量进行了定量，发现野生型细胞产生足够的过氧化氢酶来应对防御性过氧化氢，而Δ突变体可能由于无法应对宿主叶片中的过氧化氢水平而在毒力方面受到限制。我们进一步发现ArcZ调控子与参与氧化感应的转录因子（包括Fnr和ArcA）的调控子有显著重叠。此外，我们表明ArcZ在转录后水平调控，表明该系统在介导对氧化状态的适应中起作用，特别是在疾病发展过程中。
