Evolution and Ecophysiology of the Industrial Producer Hypocrea jecorina (Anamorph Trichoderma reesei) and a New Sympatric Agamospecies Related to It.
Druzhinina, I.S., Komoń-Zelazowska, M., Atanasova, L., Seidl, V., Kubicek, C.P., 2010
PLoS ONE 5(2)
a mitosporic green mould, was recognized during the WW II based on a
single isolate from the Solomon Islands and since then used in industry
for production of cellulases. It is believed to be an anamorph (asexual
stage) of the common pantropical ascomycete Hypocrea jecorina.
combined molecular evolutionary analysis and multiple methods of
phenotype profiling in order to reveal the genetic relationship of T. reesei to H. jecorina. The resulting data show that the isolates which were previously identified as H. jecorina by means of morphophysiology and ITS1 and 2 (rRNA gene cluster) barcode in fact comprise several species: i) H. jecorina/T. reesei sensu stricto which contains most of the teleomorphs (sexual stages) found on dead wood and the wild-type strain of T. reesei QM 6a; ii) T. parareesei
nom. prov., which contains all strains isolated as anamorphs from soil;
iii) and two other hypothetical new species for which only one or two
isolates are available. In silico tests for recombination and in vitro mating experiments revealed a history of sexual reproduction for H. jecorina and confirmed clonality for T. parareesei
nom. prov. Isolates of both species were consistently found worldwide
in pantropical climatic zone. Ecophysiological comparison of H. jecorina and T. parareesei
nom. prov. revealed striking differences in carbon source utilization,
conidiation intensity, photosensitivity and mycoparasitism, thus
suggesting adaptation to different ecological niches with the high
opportunistic potential for T. parareesei nom. prov.
Our data prove that T. reesei belongs to a holomorph H. jecorina and displays a history of worldwide gene flow. We also show that its nearest genetic neighbour - T. parareesei
nom. prov., is a cryptic phylogenetic agamospecies which inhabits the
same biogeographic zone. These two species thus provide a so far rare
example of sympatric speciation within saprotrophic fungi, with
divergent ecophysiological adaptations and reproductive strategies.