Endophytic Trichoderma species from rubber trees native to the Brazilian Amazon, including four new species

Abstract

Fungi belonging to the genus <i>Trichoderma</i> have been widely recognized as efficient controllers of plant diseases. Although the majority of isolates currently deployed, thus far, have been isolated from soil, endophytic <i>Trichoderma</i> spp. is considered to be a promising option for application in biocontrol. In this study, 30 endophytic <i>Trichoderma</i> isolates-obtained from the leaves, stems, and roots of wild <i>Hevea</i> spp. in the Brazilian Amazon-were analyzed using specific DNA barcodes: sequences of internal transcribed spacers 1 and 2 of rDNA (ITS region), genes encoding translation elongation factor 1-α (TEF1<i>-α</i>), and the second largest subunit of RNA polymerase II (<i>RPB</i>2). The genealogical concordance phylogenetic species recognition (GCPSR) concept was used for species delimitation. A phylogenetic analysis showed the occurrence of <i>Trichoderma</i> species, such as <i>T</i>. <i>erinaceum</i>, <i>T</i>. <i>ovalisporum</i>, <i>T</i>. <i>koningiopsis</i>, <i>T</i>. <i>sparsum</i>, <i>T</i>. <i>lentiforme</i>, <i>T</i>. <i>virens</i>, and <i>T</i>. <i>spirale</i>. Molecular and morphological features resulted in the discovery of four new species, such as <i>T</i>. <i>acreanum</i> sp. nov., <i>T</i>. <i>ararianum</i> sp. nov., <i>T</i>. <i>heveae</i> sp. nov., and <i>T</i>. <i>brasiliensis</i> sp. nov. The BI and ML analyses shared a similar topology, providing high support to the final trees. The phylograms show three distinct subclades, namely, <i>T</i>. <i>acreanum</i> and <i>T</i>. <i>ararianum</i> being paraphyletic with <i>T</i>. <i>koningiopsis</i>; <i>T</i>. <i>heveae</i> with <i>T</i>. <i>subviride</i>; and <i>T</i>. <i>brasiliensis</i> with <i>T</i>. <i>brevicompactum</i>. This study adds to our knowledge of the diversity of endophytic <i>Trichoderma</i> species in Neotropical forests and reveals new potential biocontrol agents for the management of plant diseases.