世界首个地衣真菌全基因组测序完成

记者日前从中科院微生物所获悉，该所真菌学国家重点实验室魏江春课题组与南开大学王磊课题组合作，完成了世界首个地衣真菌全基因组测序。相关成果发表于英国医学委员会下属《基因组学》杂志。

据了解，该地衣真菌为石果衣，具有连续抵抗7个月干旱的抗旱功能。科研人员从3750万个碱基的基因组中注释出9285个基因。通过对其干旱胁迫与正常培养的转录组比较分析，他们发现了1781个在诱导干旱胁迫条件下差异表达的基因。针对这些差异基因的研究表明，石果衣真菌与其他抗旱生物相比，除具有整套的抗氧化机制和有效的转录后修复能力外，在渗透压调节机制方面也与其他抗旱生物有所不同。此外，石果衣真菌具有一系列重要的干旱适应机制，包括损伤修复、能量供应和碳氮代谢的变化。

相关专家表示，该成果为进一步探明抗旱力极强的石果衣真菌的抗旱基因及其分子机制，利用其抗旱基因构建抗旱转基因植物以实现干旱沙漠生物“地毯工程”和提高旱区农业产量奠定了基础，同时为开发利用具有丰富抗逆境基因资源的地衣真菌提供了研究平台。（来源：中国科学报 郭爽）

Genome characteristics reveal the impact of lichenization on lichen-forming fungus Endocarpon pusillum Hedwig (Verrucariales, Ascomycota)

Abstract Background Lichen is a classic mutualistic organism and the lichenization is one of the fungal symbioses. The lichen-forming fungus Endocarpon pusillum is living in symbiosis with the green alga Diplosphaera chodatii Bialsuknia as a lichen in the arid regions. Results 454 and Illumina technologies were used to sequence the genome of E. pusillum. A total of 9,285 genes were annotated in the 37.5 Mb genome of E. pusillum. Analyses of the genes provided direct molecular evidence for certain natural characteristics, such as homothallic reproduction and drought-tolerance. Comparative genomics analysis indicated that the expansion and contraction of some protein families in the E. pusillum genome reflect the specific relationship with its photosynthetic partner (D. chodatii). Co-culture experiments using the lichen-forming fungus E. pusillum and its algal partner allowed the functional identification of genes involved in the nitrogen and carbon transfer between both symbionts, and three lectins without signal peptide domains were found to be essential for the symbiotic recognition in the lichen; interestingly, the ratio of the biomass of both lichen-forming fungus and its photosynthetic partner and their contact time were found to be important for the interaction between these two symbionts. Conclusions The present study lays a genomic analysis of the lichen-forming fungus E. pusillum for demonstrating its general biological features and the traits of the interaction between this fungus and its photosynthetic partner D. chodatii, and will provide research basis for investigating the nature of its drought resistance and symbiosis.

原文链接：http://www.biomedcentral.com/content/pdf/1471-2164-15-34.pdf