基于形态和分子特征的甘肃省煤污病菌分类和系统发育研究

Sooty blotch and flyspeck (SBFS) fungi are epiphytic and highly diverse, with over 90 species in more than 30 genera having been reported from different countries in the world. However, almost half of these species were inferred only based on phylogenetic analyses and have not been described. Seventeen SBFS fungal species have been reported from China. But only one species was known from Gansu Province. Gansu Province is characterized by large areas, complex landform and climate, as well as various plants and crops, providing very good conditions for high diversity of SBFS fungi. Therefore it is very necessary to carry out studies of SBFS fungi in Gansu Province. We will conduct surveys of SBFS in different areas of Gansu Province and collect SBFS samples from different hosts, clarify the taxonomy of SBFS fungi in Gansu Province based on morphological and molecular characteristics, and analyze the relationship between SBFS fungi and their hosts, geographical locations, and climate. This project will be very helpful to understand the diversity of SBFS fungi in Gansu Province, promote the taxonomy work of SBFS fungi, and provide theoretical foundation to other studies of SBFS fungi such as biology and epidemiology.

煤污病菌是一类附生在植物表面的真菌类群，种类具有丰富的多样性，世界范围内已报道的有30多个属的90多个种，但其中近半数是依据核苷酸序列分析得到的系统发育种，尚未进行鉴定描述。我国已报道的有17个种，来自甘肃省的仅有一个种。甘肃省境域辽阔，地形和气候组成复杂，植被多样，林果资源丰富，具有煤污病菌生存的良好条件。但目前国内对甘肃省煤污病菌的研究还几乎是空白。本项目拟对甘肃省不同地区、不同寄主的煤污病进行调查并采集样品，采用形态学特征和核苷酸序列分析相结合的方法对甘肃省的煤污病菌进行分类和系统发育研究，并分析煤污病菌种类组成与寄主、地理范围、气候等因素的关系，以明确甘肃省煤污病菌的多样性，促进该类群真菌的分类研究进展，并为煤污病菌其它方面如生物学特性、流行学等领域开展进一步研究提供理论基础。

目前国内关于甘肃省煤污病菌的研究还很少。本项目对甘肃省煤污病的发生情况进行了调查，调查地区包括平凉市、天水市、庆阳市、陇南市、武威市和酒泉市，并结合形态学特征和核苷酸序列分析对所得煤污病菌进行了分类鉴定。调查结果表明，在甘肃省，苹果和梨果实上煤污病发生最为普遍，且此病的发病程度与当年夏秋季节的降雨呈正相关。采集到苹果煤污病标本3701个，梨煤污病标本326个；分别得到煤污病菌纯菌株1198株和70株。甘肃省苹果和梨煤污病菌的物种多样性极为丰富，苹果煤污病菌包括至少17个属：链丝孢属、月盾霉属、多绺孢属、锥梗孢属、拟维朗那霉属、枝氯霉属、口盾霉属、后稷孢属、小拟褐鞘孢属、接瓶霉属、球腔菌属、小叠孢属、横断孢属、拟座糙孢属、Diatractium、Sarcinomyces、Sphaerulina，梨煤污病菌包括至少8个属：链丝孢属、球腔菌属、小叠孢属、锥梗孢属、拟维朗那霉属、接瓶霉属、后稷孢属、拟座糙孢属。其中，Sarcinomyces和Sphaerulina两个属是首次发现能够引起苹果煤污病，而Diatractium属则是首次在中国发现能够引起煤污病。对9个属的种进行了鉴定，其中小叠孢属有5个种；接瓶霉属和枝氯霉属分别有4个种，拟维朗那霉属有3个种，链丝孢属有2个种，后稷孢属、锥梗孢属、拟座糙孢属和多绺孢属分别有1个种。口盾霉属和球腔菌属是甘肃省苹果煤污病菌的优势属。其他煤污病菌在不同地区的分布存在差异，不同地区苹果煤污病菌的组成也不尽相同。在煤污病菌的分离培养中，交替使用新霉素、链霉素、庆大霉素和卡那霉素可避免细菌污染。改良CTAB法适用于大多数煤污病菌基因组DNA的提取，但链丝孢属煤污病菌用氯化苄法提取DNA的效果最好。