Peptaibol profiles of Iranian Trichoderma isolates

Abstract

Five Iranian Trichoderma isolates from species T. viride, T. viridescens, T. asperellum, T. longibrachiatumand T. citrinoviride -selected from the Fungal Collection of the Bu Ali Sina University, Hamedan, Iran -were investigated for their peptaibol production. All examined isolates showed remarkable antibacterial activities during the screening of their extracts for peptaibol content with a Micrococcus luteus test culture. HPLC-ESI-IT MS was used for identification and elucidation of the amino acid sequences of peptaibols. The detected peptaibol compounds contain 20 or 18 amino acid residues and belong to the trichobrachin and trichotoxin groups of peptaibols, respectively. T. longibrachiatum and T. citrinoviride produced trichobrachins, while trichotoxins could be detected in T. viride, T. viridescens and T. asperellum. Out of 37 sequences detetermined, 26 proved to be new, yet undescribed compounds, while others were identified as previously reported trichotoxins (trichotoxin A-50s and T5D2) and trichobrachins (longibrachins AI, AII, AIII, BII and BIII). Compounds within the two groups of detected peptaibols differed from each other only by a single or just a few amino acid changes.

Changes in Peptaibol Production of Trichoderma Species during In Vitro Antagonistic Interactions with Fungal Plant Pathogens

“…Longibrachin BII and BIII could be identified in peaks 1 and 2, respectively [26,49]. Pept-1951-c and Pept-1952-d [46] could also be observed in the same merged extracted [M + Na] + ion peak, similarly to longibrachin AIII and BIII, and Pept-1965-c-1 and Pept-1965-d. Pept-1966-d [46] and Pept-1965-c-1 [46] were found in peak 3 while Pept-1965-c-2 [46] could be observed in peak 4 (Figure 8).…”

“…Analysing the mass spectrum of peak 1 revealed the presence of Pept-1705-a-1 [46] ( Figure 6A). In peak 2, the peptaibols named Pept-1689-a-1 and a-2 [46] were different from the previously reported trichotoxins such as T5F [23] in the Aib residue at position 10. These two compounds were shown on the chromatograms (extracted to their [M + Na] + ions) in one merged peak and their relative amounts have not significantly changed in any of the interactions.…”

“…This peak also contains Pept-1691-a-1. In peak 3, signals related to five peptaibols, Pept-1719-a-1, Pept-1719-b-1, Pept-1705-a-3, Pept-1703-a-1 and Pept-17049-b-1 [46] were detected. These peptaibols were different from other detected trichotoxins with the presence of Ser in position 10.…”

“…Biomolecules 2020, 10, x; doi: FOR PEER REVIEW www.mdpi.com/journal/biomolecules related to trichotoxin A-50 F (Pept-1689-b-2), trichotoxin sequence 05 (Pept-1703-a-2) [25], Pept-1733b-3, Pept-1703-b-1 and Pept-33-b-4 [46] were detected. Trichotoxin sequence 05 and Pept-1703-b-1 were also seen together in the same extracted [M + Na] + peaks.…”

“…Trichotoxin sequence 05 and Pept-1703-b-1 were also seen together in the same extracted [M + Na] + peaks. In peak 6, five peptaibols were observed: Pept-1703-b-2, Pept-1747-b-1, Pept-1703-b-3, Pept-1733-b-5 [46] and trichotoxin A-50I (Pept-1717-b-1) [25]. Pept-1731-b-1 was found in peak 7, while peak 8 contained trichotoxin A50J (Pept-1731-b-2) [46] (Figure 7).…”