Department of Horticultural Science, North Carolina State University, Raleigh, NC 27695, USA.
Department of Plant Pathology, University of Florida, Gainesville, FL 32611, USA.
G3 (Bethesda). 2021 Feb 9;11(2). doi: 10.1093/g3journal/jkaa052.
Mummy berry disease, caused by the fungal pathogen Monilinia vaccinii-corymbosi (Mvc), is one of the most economically important diseases of blueberries in North America. Mvc is capable of inducing two separate blighting stages during its life cycle. Infected fruits are rendered mummified and unmarketable. Genomic data for this pathogen is lacking, but could be useful in understanding the reproductive biology of Mvc and the mechanisms it deploys to facilitate host infection. In this study, PacBio sequencing and Hi-C interaction data were utilized to create a chromosome-scale reference genome for Mvc. The genome comprises nine chromosomes with a total length of 30 Mb, an N50 length of 4.06 Mb, and an average 413X sequence coverage. A total of 9399 gene models were predicted and annotated, and BUSCO analysis revealed that 98% of 1,438 searched conserved eukaryotic genes were present in the predicted gene set. Potential effectors were identified, and the mating-type (MAT) locus was characterized. Biotrophic effectors allow the pathogen to avoid recognition by the host plant and evade or mitigate host defense responses during the early stages of fruit infection. Following locule colonization, necrotizing effectors promote the mummification of host tissues. Potential biotrophic effectors utilized by Mvc include chorismate mutase for reducing host salicylate and necrotrophic effectors include necrosis-inducing proteins and hydrolytic enzymes for macerating host tissue. The MAT locus sequences indicate the potential for homothallism in the reference genome, but a deletion allele of the MAT locus, characterized in a second isolate, indicates heterothallism. Further research is needed to verify the roles of individual effectors in virulence and to determine the role of the MAT locus in outcrossing and population genotypic diversity.
蓝莓菌核病，由真菌病原体 Monilinia vaccinii-corymbosi（Mvc）引起，是北美蓝莓最重要的经济疾病之一。Mvc 在其生命周期中能够诱导两个独立的枯萎阶段。受感染的果实会变成木乃伊状，无法销售。该病原体的基因组数据缺乏，但对于了解 Mvc 的生殖生物学以及它用于促进宿主感染的机制可能很有用。在这项研究中，利用 PacBio 测序和 Hi-C 相互作用数据为 Mvc 创建了染色体规模的参考基因组。该基因组由九个染色体组成，总长度为 30Mb，N50 长度为 4.06Mb，平均序列覆盖度为 413X。共预测和注释了 9399 个基因模型，BUSCO 分析表明，在预测的基因集中存在 1438 个搜索的保守真核基因中的 98%。鉴定了潜在的效应子，并对交配型（MAT）基因座进行了表征。生营养效应子使病原体能够避免被宿主植物识别，并在果实感染的早期阶段逃避或减轻宿主防御反应。在室腔定植后，坏死效应子促进宿主组织的木乃伊化。Mvc 可能利用的生营养效应子包括用于降低宿主水杨酸的分支酸变位酶和坏死效应子包括坏死诱导蛋白和水解酶，用于粉碎宿主组织。MAT 基因座序列表明参考基因组中存在同宗配合的潜力，但在第二个分离株中表征的 MAT 基因座缺失等位基因表明异宗配合。需要进一步研究以验证单个效应子在毒力中的作用，并确定 MAT 基因座在异交和群体基因型多样性中的作用。
