Trichoderma pseudokoningii identified based on morphology was re-identified as T. longibrachiatum through molecular characterization

Abstract

Trichoderma pseudokoningii and T. longibrachiatum have many morphological similarities viz,diffusion of yellow pigment through the agar, sparsely branched conidiophores having a high proportion of solitary phialides; size and shape of phialides, shape and colour of conidia and presence of chlamydospores with minute differences in conidiation and size of conidia. Due to the overlapping characters, the morphology alone is not sufficient in differentiating these two species, therefore Internal Transcribed Spacer (ITS) region and Translation Elongation Factor 1 alpha (tef1) gene were used to confirm identification of T. pseudokoningii and T. longibrachiatum. Thirty two isolates of Trichoderma species were collected from different parts of India and identified as T. pseudokoningii (17 isolates) and T. longibrachiatum (15 isolates) based on morphology. But all the 17 T. pseudokoningii isolates have been proved as T. longibrachiatum through ITS region and tef1 gene sequence analysis. Apart from the NCBI-BLAST, these Indian T. pseudokoningii isolates were confirmed as T. longibrachiatum also through Trichokey and TrichoBLAST. There is only one Indian accession (ITS sequence) available in NCBI database in the name of T. pseudokoningii (JX500737) from Mizoram state, but it is also not proved to be T. pseudokoningii, when it was analysed through Trichokey (showed as T.effusum) and TrichoBLAST (T. citrinoviride). The present analysis confirmed that Trichoderma isolates identified as T. pseudokoningii in India are truly T. longibrachiatum.