Metatranscriptomic comparison of grape berry microbiome during noble and grey rot

Botrytis cinerea is well-known for causing gray rot (GR) of grapevine (Vitis vinifera). Under certain environmental conditions, however, B. cinerea can cause noble rot (NR) of berries, the basis for producing the sweet aszu wines. Little is known about the fungal and plant metabolic genes involved in NR and how they differ from GR.We analyze metatranscriptomic data generated from healthy (H), NR and GR grape berries collected from the Tokaj wine region in Hungary. Functional gene expression profiles of V. vinifera,, B. cinerea and other fungi are compared among rot types, sampling months, and physical characteristics of berries using multivariate analyses of variance, differential gene expressions, gene ontology and functional pathway enrichment.Our results show that harvest time influences functional gene profiles in NR and GR berries and that many differently expressed genes correspond to processes linked to sensory differences between NR and GR berries, with implications for wine makers.

灰葡萄孢（Botrytis cinerea）因引发葡萄（Vitis vinifera）灰霉病（gray rot, GR）而广为人知。但在特定环境条件下，灰葡萄孢可引发浆果贵腐病（noble rot, NR），而这正是酿制甜阿苏葡萄酒的核心基础。目前学界对贵腐病相关的真菌与植物代谢基因，以及其与灰霉病相关基因的差异机制仍知之甚少。本研究对采自匈牙利托卡伊葡萄酒产区的健康（healthy, H）、贵腐病与灰霉病葡萄浆果的宏转录组（metatranscriptomic）数据进行分析。研究采用多变量方差分析、差异基因表达分析、基因本体（gene ontology, GO）注释与功能通路富集分析等方法，对比了葡萄、灰葡萄孢及其他真菌的功能基因表达谱在不同病害类型、采样月份以及浆果物理特性间的差异。研究结果表明，采收时间会影响贵腐病与灰霉病浆果的功能基因表达谱；且大量差异表达基因与两类病害浆果的感官特性差异相关，这一发现对葡萄酒酿造产业具有实际指导意义。