Fungal chitinases are hydrolytic enzymes responsible for degradation of chitin. Chitinases are involved in several aspects of fungal biology, including cell wall remodelling during hyphal growth, conidial germination, autolysis, mycoparasitism and nutrient acquisition. They are divided into three distinct phylogenetic groups; A, B and C. Chitinases from the C group show structural similarities with the killer toxin zymocin produced by the yeast Kluyveromyces lactis and it is speculated that they have a similar function in filamentous ascomycetes, by facilitating penetration of toxins into cells of competing individuals. Genome analyses show that certain fungal species with a mycoparasitic lifestyle contain high numbers of killer toxin-like chitinases, compared with specialized saprotrophs and plant pathogens. Recent developments within this research field have revealed considerable variation in the modular structure and regulation of killer toxin-like chitinases, suggesting more diverse roles than merely fungal-fungal interactions. In this review, we summarize the current knowledge about this intriguing class of chitinases, including their modular structure, evolution, gene regulation, and functional analyses in mycoparasitic as well as in saprotrophic species. We also propose important questions for future research.

真菌几丁质酶是负责降解几丁质的水解酶。几丁质酶与真菌生物学有关，包括菌丝生长过程中的细胞壁重塑，分生孢子萌发，自溶，支原体寄生和营养获取。它们分为三个不同的系统发育组。A，B和C.C组的几丁质酶与乳酸克鲁维酵母产生的杀伤毒素zymocin具有结构相似性并且推测它们通过促进毒素渗透到竞争个体的细胞中而在丝状子囊菌中具有相似的功能。基因组分析表明，与专门的腐生菌和植物病原体相比，某些具有霉菌寄生性生活方式的真菌物种含有大量的杀伤毒素样几丁质酶。该研究领域内的最新进展表明，杀伤性毒素样几丁质酶的模块化结构和调控存在很大差异，这表明其作用不仅是真菌-真菌相互作用，而且还多种多样。在这篇综述中，我们总结了关于这种有趣的几丁质酶的当前知识，包括它们的模块结构，进化，基因调控以及在真菌寄生和腐养物种中的功能分析。