AUTHOR=Umar Aisha , Elshikh Mohamed S. , Aljowaie Reem M. , Hussein Juma Mahmud , Dufossé Laurent , Wu Chenghong , Lu Junxing 

TITLE=Competitive antagonistic action of laccase between Trichoderma species and the newly identified wood pathogenic Ganoderma camelum

JOURNAL=Frontiers in Microbiology

VOLUME=15

YEAR=2024

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2024.1408521

DOI=10.3389/fmicb.2024.1408521

ISSN=1664-302X

ABSTRACT=<p><italic>Ganoderma</italic>, a well-known genus in the Ganodermataceae family, has caused the extinction of several tree species due to its pathogenicity. This study explored the pathogenic effect of a newly identified <italic>Ganoderma</italic> species on trees and its competitive efficiency against <italic>Trichoderma</italic> species. <italic>Ganoderma camelum</italic> sp. nov. is characterized by small sessile basidiomata and a velvety, soft, camel-brown pileus. Phylogenetic analysis and ITS rDNA sequences indicated that the species were <italic>Trichoderma</italic> and <italic>Ganoderma camelum</italic>. Both fungal species competed antagonistically by secreting laccase. The laccase activity of <italic>G. camelum</italic>, with a value of 8.3 ± 4.0 U/mL, demonstrated the highest competitive activity against <italic>Trichoderma</italic> species. The laccase produced by <italic>T. atroviride</italic> (2.62 U/mL) was most effective in countering the pathogenic action of the novel <italic>G. camelum</italic>. The molecular weights of laccase were determined using SDS-PAGE (62.0 kDa for <italic>G. camelum</italic> and 57.0 kDa for <italic>T. atroviride</italic>). Due to the white rot induced by this <italic>Ganoderma</italic> species in the host tree, <italic>G. camelum</italic> showed the highest percentage inhibition of radial growth (76.3%) compared to <italic>T. atroviride</italic> (28.7%). This study aimed to evaluate the competitive antagonistic activity of <italic>Ganoderma</italic> and <italic>Trichoderma</italic> on malt extract agar media in the context of white rot disease in the host tree. This study concluded that the laccase from <italic>G. camelum</italic> caused weight loss in rubber wood blocks through laccase action, indicating tissue injury in the host species. Therefore, it was also concluded that <italic>G. camelum</italic> was more effective in pathogenic action of the host and resisted the biological action of <italic>T. atroviride</italic>. In principal components analysis (PCA), all the species associated with laccase exhibited a very strong influence on the variability of the system. The PIRG rate (percentage inhibition of radial growth) was strongly and positively correlated with laccase activity.</p>