AUTHOR=Sefer Özlem , Özsoy Esma , Yörük Emre , Özkale Evrim 

TITLE=Determining the biocontrol capacities of Trichoderma spp. originating from Turkey on Fusarium culmorum by transcriptional and antagonistic analyses

JOURNAL=Frontiers in Fungal Biology

VOLUME=4

YEAR=2023

URL=https://www.frontiersin.org/journals/fungal-biology/articles/10.3389/ffunb.2023.1278525

DOI=10.3389/ffunb.2023.1278525

ISSN=2673-6128

ABSTRACT=<p>In this study aiming to investigate potential fungal biocontrol agents for <italic>Fusarium culmorum</italic>, several isolates of <italic>Trichoderma</italic> spp. were evaluated for their antagonistic effects by means of transcriptional analyses. At first, 21 monosporic <italic>Trichoderma</italic> spp. isolates were obtained from natural wood debris and wood area soils in Manisa, Turkey. <italic>Trichoderma</italic> spp. Isolates were identified as belonging to four different species (<italic>T. atroviride, T. harzianum, T. koningii</italic>, and <italic>T. brevicompactum</italic>) by <italic>tef1-α</italic> sequencing. Then, the linear growth rate (LGR) of each species was calculated and determined to be in a range between 13.22 ± 0.71 mm/day (<italic>T. atroviride</italic> TR2) and 25.06 ± 1.45 mm/day (<italic>T. harzianum</italic> K30). Inter-simple sequence repeat (ISSR) genotyping validated the <italic>tef1-α</italic> sequencing results by presenting two sub-clusters in the dendrogram. We determined the genetically most similar (TR1 &amp; TR2; 97.77%) and dissimilar (K9 &amp; K17; 40.40%) individuals belonging to the same and different species, respectively. Dual sandwich culture tests (which are useful for antagonism studies) revealed that <italic>T. harzianum</italic> K21 (the least suppressive) and <italic>T. brevicompactum</italic> K26 (the most suppressive) isolates suppressed <italic>F. culmorum</italic> with growth rates of 3% and 46%, respectively. Expressions of genes previously associated with mycoparasitism-plant protection-secondary metabolism (<italic>nag1</italic>, <italic>tgf-1</italic>, and <italic>tmk-1</italic>) were tested by quantitative real-time polymerase chain reaction (qRT-PCR) in both those isolates. While there were no significant differences (p&gt;0.05) in expression that were present in the K21 isolate, those three genes were upregulated with fold change values of 2.69 ± 0.26 (p&lt;0.001), 2.23 ± 0.16 (p&lt;0.001), and 5.38 ± 2.01 (p&lt;0.05) in K26, meaning that the presence of significant alteration in the physiological processes of the fungus. Also, its mycoparasitism potential was tested on <italic>Triticum aestivum</italic> L. cv Basribey <italic>in planta</italic>, which was infected with the <italic>F. culmorum</italic> FcUK99 strain. Results of the trials, including specific plant growth parameters (weight or length of plantlets), confirmed the mycoparasitic potential of the isolate. It can be concluded that (i) <italic>nag1</italic>, <italic>tgf-1</italic>, and <italic>tmk-1</italic> genes could be approved as reliable markers for evaluation of BCA capacities of <italic>Trichoderma</italic> spp. and (ii) the <italic>T. brevicompactum</italic> K26 strain can be suggested as a promising candidate for combating in <italic>F. culmorum</italic> diseases following the necessary procedures to ensure it is non-hazardous and safe.</p>