A phylogeny for the plant pathogen Piptoporellus baudonii using a multigene data set

Piptoporellus baudonii is proposed as a new combination for Laetiporus baudonii in the Polyporales (Basidiomycota) based on morphological and molecular features. This parasitic macrofungus attacks cashew trees, Eucalyptus, cassava, Tectona, and some indigenous trees in southern regions of Tanzania and poses a serious threat to agroforestry and livelihood conditions in the area. Phylogenetic trees were produced from partial sequences of three rDNA gene regions and a portion of translation elongation factor 1-alpha (TEF1) gene of Laetiporus baudonii for comparisons with samples from the antrodia clade. Our results reveal a strongly supported group of L. baudonii with Piptoporellus in Fomitopsidaceae. Piptoporellus baudonii shares many morphological features with other members of Piptoporellus but differs from them in having broadly ellipsoid or rarely ovoid basidiospores. Both morphological and phylogenetic evidence justify the placement of L. baudonii in Piptoporellus together with the three other known species in the genus.

本研究基于形态学与分子特征，将原隶属于硫色孔菌属（Laetiporus）的Laetiporus baudonii重新组合为褶孔栓菌属（Piptoporellus）的Piptoporellus baudonii新组合，该类群隶属于担子菌门（Basidiomycota）多孔菌目（Polyporales）。该寄生大型真菌可侵染坦桑尼亚南部地区的腰果树、桉树、木薯、柚木属（Tectona）植物以及部分本土树种，对当地农林业生产与民众生计造成严重威胁。研究基于Laetiporus baudonii的3个核糖体DNA（rDNA）基因区域的部分序列，以及翻译延伸因子1-α（translation elongation factor 1-alpha, TEF1）基因的部分片段构建系统发育树，用以与安东孔菌支系（antrodia clade）的样本进行比对分析。系统发育分析结果显示，L. baudonii与褶孔栓菌属（Piptoporellus）物种聚为一个高支持率的单系群，该类群隶属于白肉迷孔菌科（Fomitopsidaceae）。鲍氏褶孔栓菌（Piptoporellus baudonii）与该属的其他物种具有诸多共同形态特征，但本种的担孢子（basidiospores）呈宽椭圆形，少数为卵圆形，以此与同属其他类群相区分。综合形态学与系统发育证据，足以支持将L. baudonii归入褶孔栓菌属（Piptoporellus），该属目前已知另有3个物种。