Hans Merensky Chair in Avocado Research, Department of Biochemistry; Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute, University of Pretoria, Pretoria, 0002, South Africa.
BMC Genomics. 2024 May 2;25(1):435. doi: 10.1186/s12864-024-10358-3.
The oomycete Phytophthora cinnamomi is a devastating plant pathogen with a notably broad host range. It is the causal agent of Phytophthora root rot (PRR), arguably the most economically important yield-limiting disease in Persea americana (avocado). Despite this, our understanding of the mechanisms P. cinnamomi employs to infect and successfully colonize avocado remains limited, particularly regarding the pathogen's ability to maintain its biotrophic and necrotrophic lifestyles during infection. The pathogen utilises a large repertoire of effector proteins which function in facilitating and establishing disease in susceptible host plants. Crinkling and necrosis effectors (CRN/Crinklers) are suspected to manipulate cell death to aid in maintenance of the pathogens biotrophic and necrotrophic lifestyles during different stages of infection. The current study identified 25 P. cinnamomi CRN effectors from the GKB4 genome using an HMM profile and assigned putative function to them as either cell death inducers or suppressors. Function was assigned to 10 PcinCRNs by analysing their RNA-seq expression profiles, relatedness to other functionally characterised Phytophthora CRNs and tertiary protein predictions. The full-length coding sequences for these PcinCRNs were confirmed by Sanger sequencing, six of which were found to have two divergent alleles. The presence of alleles indicates that the proteins encoded may perform contradicting functions in cell death manipulation, or function in different host plant species. Overall, this study provides a foundation for future research on P. cinnamomi infection and cell death manipulation mechanisms.
卵菌纲植物致病疫霉是一种具有广泛宿主范围的破坏性植物病原体。它是植物疫霉根腐病（PRR）的病原体，可能是鳄梨（Persea americana）中最重要的经济上限制产量的疾病。尽管如此，我们对疫霉菌感染和成功定殖鳄梨的机制的理解仍然有限，特别是关于病原体在感染过程中维持其生物营养和坏死营养生活方式的能力。病原体利用大量效应蛋白来促进和建立感病宿主植物中的疾病。卷曲和坏死效应物（CRN/Crinklers）被怀疑操纵细胞死亡以帮助维持病原体在感染不同阶段的生物营养和坏死营养生活方式。本研究使用 HMM 分析从 GKB4 基因组中鉴定了 25 个疫霉菌 CRN 效应物，并将它们的功能分配为细胞死亡诱导剂或抑制剂。通过分析其 RNA-seq 表达谱、与其他功能表征的疫霉菌 CRN 的相关性以及三级蛋白预测，为 10 个 PcinCRNs 分配了功能。通过 Sanger 测序证实了这些 PcinCRNs 的全长编码序列，其中 6 个被发现具有两个分歧的等位基因。等位基因的存在表明，编码的蛋白质可能在细胞死亡操纵中具有矛盾的功能，或者在不同的宿主植物物种中发挥作用。总的来说，这项研究为疫霉菌感染和细胞死亡操纵机制的未来研究提供了基础。
