Three new species of soil-inhabiting Trichoderma from southwest China.

Min Qiao,Zenfen Yu,Zhe Zhang,Jianping Xu,Xing Du

doi:10.3897/mycokeys.44.30295

Abstract

Fungi in the genus Trichoderma are widely distributed in China, including in Yunnan province. In this study, we report three new soil-inhabiting species in Trichoderma, named as T.kunmingense, T.speciosum and T.zeloharzianum. Their colony and mycelial morphology, including features of asexual states, were described. For each species, their DNA sequences were obtained from three loci, the internal transcribed spacer (ITS) regions of the ribosomal DNA, the translation elongation factor 1-α encoding gene (tef1) and the gene encoding the second largest nuclear RNA polymerase subunit (rpb2). Our analyses indicated that the three new species showed consistent divergence amongst each other and from other known and closely related species. Amongst the three, T.speciosum and T.kunmingense belong to the Viride Clade. Specifically, T.speciosum is related to three species – T.hispanicum, T.samuelsii and T.junci and is characterised by tree-like conidiophores, generally paired branches, curved terminal branches, spindly to fusiform phialides and subglobose to globose conidia. In contrast, T.kunmingense morphologically resembles T.asperellum and T.yunnanense and is distinguished by its pyramidal conidiophores, ampulliform to tapered phialides, discrete branches and ovoidal, occasionally ellipsoid, smooth-walled conidia. The third new species, T.zeloharzianum, is a new member of the Harzianum Clade and is closely associated with T.harzianum, T.lixii and T.simmonsii but distinguished from them by having smaller, subglobose to globose, thin-walled conidia.

Highlights

The genus Trichoderma Pers. (Ascomycota, Sordariomycete, Hypocreales, teleomorph Hypocrea Fr.) is cosmopolitan, often existing as saprophytes in a diversity of ecosystems, such as agricultural fields, prairies, forests and salt marshes (Gond et al 2007, Verma et al 2007, Gazis and Chaverri 2010)
Phylogenetic positions of the new species were ascertained by analyses of the combined tef1, rpb2 and internal transcribed spacer (ITS) dataset containing 2831 characters, of which 487 characters were constant, 2344 were variable
Of the three new species, T. speciosum and T. kunmingense belonged to the Viride Clade, whereas T. zeloharzianum were located in the Harzianum Clade

Summary

Introduction

The genus Trichoderma Pers. (Ascomycota, Sordariomycete, Hypocreales, teleomorph Hypocrea Fr.) is cosmopolitan, often existing as saprophytes in a diversity of ecosystems, such as agricultural fields, prairies, forests and salt marshes (Gond et al 2007, Verma et al 2007, Gazis and Chaverri 2010). (Ascomycota, Sordariomycete, Hypocreales, teleomorph Hypocrea Fr.) is cosmopolitan, often existing as saprophytes in a diversity of ecosystems, such as agricultural fields, prairies, forests and salt marshes (Gond et al 2007, Verma et al 2007, Gazis and Chaverri 2010). A few species of Trichoderma are effective in attacking or inhibiting other fungi through their secondary metabolites and these fungi have been exploited as potential biocontrol agents against plant pathogens (Degenkolb et al 2008, Cheng et al 2012, Lopes et al 2012, Mukherjee et al 2013). A few Trichoderma species are crop pathogens and can produce toxins to spoil food. T. aggressivum can cause significant crop loss to mushroom production (Oda et al 2009, Schuster and Schmoll 2010, Kim et al 2012, 2013)

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Conclusion