前期研究发现灰葡萄孢群体中出现黑色菌系（占99.4%）、黄黑菌系（0.1%）和黄色菌系（0.5%）的分化。前两者产生黑色菌核，含黑色素，最后一类产生黄色菌核，缺黑色素。三类菌系菌丝体和分生孢子均含有黑色素。可见，黄色菌系产生与菌核黑色素合成受阻有关。黄色菌系遗传稳定，致病力较黑色菌系强，存在流行风险。鉴此，我们提出研究黄色菌系产生的分子机制及流行风险。项目拟采用黄色菌系和黑色菌系杂交的方法研究黄色菌核性状的遗传模式，采用转录组和小RNA分析技术及基因敲除技术挖掘与黄色菌核形成相关的基因和小RNA，以揭示黄色菌系产生的分子机制。项目还将比较黄色菌系和黑色菌系的生物学特性、生态适应性、竞争性致病能力、控制条件下的多季流行效率及自然发生频率，以评估黄色菌系的流行风险。项目的完成将加深对灰葡萄孢群体演化及机制的认识，进一步明确菌核在灰葡萄孢生活史中扮演的角色，为发展防治灰霉病新策略提供理论依据。

Our previous studies indicated that the populations of Botrytis cinerea evolved three dinstinct types based on sclerotial color: the black-sclerotial type (accounting for 99.4%), the yellow-and-black-sclerotial type (accounting for 0.1%) and the yellow-sclerotial type (accounting for 0.5%). The former two types formed black-colored sclerotia with accumulation of melanin in the rind tissue, whereas the last type forms yellow-colored sclerotia without accumulation of the melanin in the rind tissue. The strains of the all the three types have melanin accumulation both in hyphae and in conidia. Therefore, the yellow-sclerotial strains (YS) of B. cinerea might be formed by suppression of melanin biosynthyesis during sclerotial development. We also found that formation of the yellow-colored sclerotia by the YS strains is a genetically-stable trait and the YS strains had stronger pathogenicity than the black sclerotial strains (BS) of B. cinerea. Therefore, the YS strains of B. cinerea have a epidemic risk in causing diseases. Based on these results, we proposed to elucidate the molecular mechanisms responsible for formation of the YS strains and to evaluate the epidemic risk of the YS strains. The contents for the former aspect include: (i) use of hybridization between the BS and the YS strains of B. cinerea to elucidate the genetic model for formation of the yelllow-colored sclerotia, and (ii) use of molecular techniques such as transcriptome profiling, small RNA (sRNA)-sequencing and gene disruption to screen the genes or the small RNAs (sRNAs) related to development of yellow-colored sclerotia. The contents for the latter aspect include: (i) comparison of the BS strains and the YS strains in development-related biological characteristics, ecological adaptation-related characteristics, competiability and multiple-season epidemics under controlled conditions, and (ii) detection of the natural occurrence frequencies of both BS strains and the YS strains in different geographical regions. The results from the project will advance our knowledge on the evolution and evolution-related mechanisms in populations of B. cinerea, will help us to further understand the role of the sclerotia formed by B. cinerea in the natual life history of this fungus, and will lay a solid foundation for initiation of some novel strategies (or methods) for control of gray mold diseases caused by B. cinerea.