Deletion of the Nonribosomal Peptide Synthetase Gene nps1 in the Fungus Clonostachys rosea Attenuates Antagonism and Biocontrol of Plant Pathogenic Fusarium and Nematodes

Abstract

Secondary metabolites produced by biological control agents may influence the outcome of their interactions with plant pathogenic microorganisms and plants. In the present study, we investigated the role of the nonribosomal peptide synthetase gene nps1 expressed by the biocontrol fungus Clonostachys rosea. A gene expression analysis showed that nps1 was induced during confrontations with the plant pathogenic fungus Botrytis cinerea. Gene deletion strains of nps1 displayed increased growth rates and conidiation. However, the nematicidal activity of culture filtrates from C. rosea Δnps1 strains was significantly weaker than that from wild-type filtrates (P ≤ 0.001); after 24 h of incubation with culture filtrates from nps1 deletion strains, only 13 to 33% of a mixed community of nematodes were dead compared with 42% of nematodes incubated with wild-type culture filtrates. The Δnps1 strains also showed reduced biocontrol efficacy during pot experiments, thus failing to protect wheat seedlings from foot rot disease caused by the plant pathogenic fungus Fusarium graminearum. Furthermore, C. rosea Δnps1 strains were not able to reduce populations of plant-parasitic nematodes in soil or in roots of wheat as efficiently as the wild-type strain. Both C. rosea wild-type and Δnps1 strains increased the dry shoot weight and shoot length of wheat by 20 and 13%, respectively. We showed that NPS1, a putative nonribosomal peptide synthetase encoded by nps1, is a biocontrol factor, presumably by producing a hitherto unknown nonribosomal peptide compound with antifungal and nematicidal properties that contributes to the biocontrol properties of C. rosea.

Biology and applications of Clonostachys rosea

“…Therefore, plenty of biocontrol-related genes in C. rosea were obtained (Kosawang et al 2014;Sun et al 2015aSun et al , 2015bLysøe et al 2017;Demissie et al 2018;Nygren et al 2018). Genes encoding nonribosomal peptide synthetase, transcription factor, transaldolase, ABC transporter, zearalenone lactonohydrolase and hydrophobin were verified to be involved in C. rosea against fungal plant pathogens through gene deletion (Dubey et al 2014;Kosawang et al 2014;Dubey et al 2016;Liu et al 2016;Sun et al 2018;Iqbal et al 2019). As the number of identified biological control-related genes available increases, the likelihood of improving the biological control ability of C. rosea through gene transformation and overexpression increases.…”

Isolation, Characterization and Targeted Metabolic Evaluation of Endophytic Fungi Harbored in 14 Seed-Derived Hypericum Species

“…and the lack of C. rosea was reported [23,25]. It should be pointed out that C. rosea attenuates antagonism to Fusarium probably by a yet unknown peptide encoded by the non-ribosomal peptide synthetase gene nps1 [30].…”

Cell Wall Biogenesis Protein Phosphatase CrSsd1 Is Required for Conidiation, Cell Wall Integrity, and Mycoparasitism in Clonostachys rosea

“…In our current study, ΔCrSsd1 deletion mutants exhibited reduced hyphal growth, suggesting diverse functions for CrSsd1 in different fungal pathogens. The ΔCrSsd1 strain also showed a significant reduction in conidiation, which plays important roles in the completion of the fungal life cycle, and the ability to produce conidia is essential for successful colonization and mycoparasitism (Iqbal et al, 2019;Kong et al, 2019;Sun et al, 2019b). These phenotypes indicate that CrSsd1 is required for vegetative growth and asexual reproduction.…”