Genomics of host and habitat adaption in an entomopathogenic fungus

以昆虫病原真菌为基础的生物农药在世界范围内广泛应用于多种害虫的生物防治。在之前的一项研究（DST-DAAD合作项目2003-2006）中，我们检测了球孢白僵菌在各种昆虫表皮感染过程中的差异表达基因，并确定了一组可能在毒力和致病性中起作用的基因。对这些基因进行详细的分子和功能表征，可以为提高球孢白杆菌类生物农药的药效靶点提供有希望的途径。作为我们之前工作的续集，鉴定基因的基因表达模式将通过定量Real-Time-PCR进一步表征。此外，将对各自的全长基因进行序列分析。最近的研究（Bidochka et al. 2002）进一步揭示了球孢白僵菌不同的遗传群与不同的生境类型有关，这对这种真菌作为生物防治剂的效用有明显的影响。这种适应栖息地的遗传基础尚未被确定。通过将相同的球孢白僵菌分离物应用于温带（德国）和热带（印度）土壤，并监测其在根际定殖过程中的任何遗传变化，我们的目标是确定与生境适应过程相关的候选基因，这是这种真菌普遍存在的潜在特征。

Biopesticides based on entomopathogenic fungi are used worldwide for biological control of many insect pests. In a previous study (DST–DAAD collaboration project 2003–2006) we examined differentially expressed genes in the fungus Beauveria bassiana during the infection process of various insect cuticles and identified a subset of genes having a putative role in virulence and pathogenicity. Detailed molecular and functional characterization of these genes could be a promising approach to get hold of targets for improving the efficiency of B. bassiana based biopesticides. As a sequel to our previous work, gene expression patterns of the identified genes will be further characterized through quantitative Real-Time-PCR. In addition, sequence analysis of the respective full-length genes will be carried out. Recent studies (Bidochka et al. 2002) have further revealed that distinct genetic groups of B. bassiana are associated with different habitat types having obvious implications in the utility of this fungus as a biocontrol agent. The genetic basis of this habitat adaptation has not been identified yet. By applying the same B. bassiana isolate to temperate (German) and tropical (Indian) soils and monitoring any genetic changes during the course of colonization of the rhizophere, we aim to identify candidate genes relevant for the habitat adaptation process which is the underlying feature for the ubiquitous nature of this fungus.