Research Area Molecular Biotechnology and Microbiology, Institute of Chemical Engineering, Vienna University of Technology, Gumpendorferstrasse 1a, Wien, Austria.
BMC Microbiol. 2013 May 16;13:108. doi: 10.1186/1471-2180-13-108.
Eukaryotic organisms employ cell surface receptors such as the seven-transmembrane G protein-coupled receptors (GPCRs) as sensors to connect to the environment. GPCRs react to a variety of extracellular cues and are considered to play central roles in the signal transduction in fungi. Several species of the filamentous ascomycete Trichoderma are potent mycoparasites, i.e. can attack and parasitize other fungi, which turns them into successful bio-fungicides for the protection of plants against fungal phytopathogens. The identification and characterization of GPCRs will provide insights into how Trichoderma communicates with its environment and senses the presence of host fungi.
We mined the recently published genomes of the two mycoparasitic biocontrol agents Trichoderma atroviride and Trichoderma virens and compared the identified GPCR-like proteins to those of the saprophyte Trichoderma reesei. Phylogenetic analyses resulted in 14 classes and revealed differences not only among the three Trichoderma species but also between Trichoderma and other fungi. The class comprising proteins of the PAQR family was significantly expanded both in Trichoderma compared to other fungi as well as in the two mycoparasites compared to T. reesei. Expression analysis of the PAQR-encoding genes of the three Trichoderma species revealed that all except one were actually transcribed. Furthermore, the class of receptors with a DUF300 domain was expanded in T. atroviride, and T. virens showed an expansion of PTH11-like receptors compared to T. atroviride and T. reesei.
Comparative genome analyses of three Trichoderma species revealed a great diversity of putative GPCRs with genus- and species- specific differences. The expansion of certain classes in the mycoparasites T. atroviride and T. virens is likely to reflect the capability of these fungi to establish various ecological niches and interactions with other organisms such as fungi and plants. These GPCRs consequently represent interesting candidates for future research on the mechanisms underlying mycoparasitism and biocontrol.
真核生物利用细胞表面受体（如七跨膜 G 蛋白偶联受体（GPCRs））作为传感器与环境连接。GPCR 对各种细胞外信号作出反应，被认为在真菌中的信号转导中发挥核心作用。几种丝状子囊菌木霉属是有效的真菌捕食者，即可以攻击和寄生其他真菌，使它们成为保护植物免受真菌病原体侵害的成功生物杀菌剂。GPCR 的鉴定和表征将深入了解木霉属如何与环境进行交流以及感知宿主真菌的存在。
我们挖掘了最近发表的两种生防剂木霉属拟青霉和木霉绿僵菌的基因组，并将鉴定出的 GPCR 样蛋白与腐生菌里氏木霉进行了比较。系统发育分析产生了 14 个类群，不仅揭示了这三个木霉属种之间的差异，也揭示了木霉属与其他真菌之间的差异。PAQR 家族蛋白组成的类群在木霉属中与其他真菌相比显著扩张，在两种真菌捕食者中与里氏木霉相比也显著扩张。对三个木霉属种的 PAQR 编码基因进行表达分析表明，除一个外，所有基因实际上都有转录。此外，在木霉属拟青霉中，具有 DUF300 结构域的受体类群扩张，与木霉属拟青霉和里氏木霉相比，木霉绿僵菌表现出 PTH11 样受体的扩张。
对三个木霉属种的比较基因组分析揭示了具有属和种特异性差异的大量假定 GPCR。真菌捕食者木霉属拟青霉和木霉绿僵菌中某些类群的扩张可能反映了这些真菌建立各种生态位以及与真菌和植物等其他生物体相互作用的能力。这些 GPCR 因此成为未来研究真菌捕食和生物防治机制的有趣候选物。
