Evolution of novel wood decay mechanisms in Agaricales revealed by the genome sequences of Fistulina hepatica and Cylindrobasidium torrendii

Wood decay mechanisms in Agaricomycotina have been traditionally separated in two categories termed white and brown rot. Recently the accuracy of such a dichotomy has been questioned. Here, we present the genome sequences of the white rot fungus Cylindrobasidium torrendii and the brown rot fungus Fistulina hepatica both members of Agaricales, combining comparative genomics and wood decay experiments. Cylindrobasidium torrendii is closely related to the white-rot root pathogen Armillaria mellea, while F. hepatica is related to Schizophyllum commune, which has been reported to cause white rot. Our results suggest that C. torrendii and S. commune are intermediate between white-rot and brown-rot fungi, but at the same time they show characteristics of decay that resembles soft rot. Both species cause weak wood decay and degrade all wood components but leave the middle lamella intact. Their gene content related to lignin degradation is reduced, similar to brown-rot fungi, but both have maint...传统上，伞菌亚门(Agaricomycotina)的木材腐朽机制被划分为白腐与褐腐两大类别。近年来，这种二分法的准确性受到了学界的质疑。本研究报道了白腐真菌(white rot fungus)托伦圆筒柄霉（Cylindrobasidium torrendii）与褐腐真菌(brown rot fungus)肝色牛舌菌（Fistulina hepatica）的基因组序列，二者均隶属于伞菌目(Agaricales)，研究结合比较基因组学(comparative genomics)与木材腐朽实验(wood decay experiments)开展。托伦圆筒柄霉与白腐型根部病原菌(root pathogen)蜜环菌(Armillaria mellea)亲缘关系密切，而肝色牛舌菌则与已被报道可引发白腐的裂褶菌(Schizophyllum commune)亲缘关系相近。研究结果显示，托伦圆筒柄霉与裂褶菌处于白腐真菌与褐腐真菌的过渡类群，但同时表现出类似软腐的腐朽特征。两种真菌均仅引发微弱的木材腐朽，可降解全部木材组分却保持胞间层(middle lamella)完整无损；其与木质素降解(lignin degradation)相关的基因组成本有所减少，这一点与褐腐真菌相似，但二者均维持了