Natural variation of root lesion nematode antagonism in the biocontrol fungus Clonostachys rosea and identification of biocontrol factors through genome-wide association mapping

Mudassir Iqbal, Martin Broberg, Deepak Haarith, Anders Broberg, Kathryn E. Bushley, Mikael Brandström Durling, Maria Viketoft, Dan Funck Jensen, Mukesh Dubey, Magnus Karlsson

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Biological control is a promising approach to reduce plant diseases caused by nematodes to ensure high productivity in agricultural production. Large-scale analyses of genetic variation in fungal species used for biocontrol can generate knowledge regarding interaction mechanisms that can improve efficacy of biocontrol applications. In this study, we performed a genome-wide association study (GWAS) for in vitro antagonism against the root lesion nematode Pratylenchus penetrans in 53 previously genome re-sequenced strains of the biocontrol fungus Clonostachys rosea. Nematode mortality in C. rosea potato dextrose broth (PDB) culture filtrates was highly variable and showed continuous variation (p '.001) between strains, indicating a polygenic inheritance. Twenty-one strains produced culture filtrates with higher (p ≤.05) nematode mortality compared with the PDB control treatment, while ten strains lowered (p ≤.05) the mortality. The difference in in vitro antagonism against P. penetrans correlated with antagonism against the soybean cyst nematode Heterodera glycines, indicating lack of host specificity in C. rosea. An empirical Bayesian multiple hypothesis testing approach identified 279 single nucleotide polymorphism markers significantly (local false sign rate ' 10–10) associated with the trait. Genes present in the genomic regions associated with nematicidal activity included several membrane transporters, a chitinase and genes encoding proteins predicted to biosynthesize secondary metabolites. Gene deletion strains of the predicted nonribosomal peptide synthetase genes nps4 and nps5 were generated and showed increased (p ≤.001) fungal growth and conidiation rates compared to the wild type. Deletion strains also exhibited reduced (p '.001) nematicidal activity and reduced (p ≤.05) biocontrol efficacy against nematode root disease and against fusarium foot rot on wheat. In summary, we show that the GWAS approach can be used to identify biocontrol factors in C. rosea, specifically the putative nonribosomal peptide synthetases NPS4 and NPS5.

Original languageEnglish (US)
Pages (from-to)2264-2283
Number of pages20
JournalEvolutionary Applications
Volume13
Issue number9
DOIs
StatePublished - Oct 1 2020

Bibliographical note

Funding Information:
The authors thank the Swedish Research Council for Environment, Agricultural Sciences and Spatial Planning (FORMAS, grant numbers 220‐2014‐289 and 942‐2015‐1128), the Plant Protection Platform and the SLU Centre for Biological Control (CBC) at the Swedish University of Agricultural Sciences for financially supporting this study. We thank Annika Gustafsson for preparing the formulations. C. rosea

Publisher Copyright:
© 2020 The Authors. Evolutionary Applications published by John Wiley & Sons Ltd

Copyright:
Copyright 2020 Elsevier B.V., All rights reserved.

Keywords

  • Clonostachys rosea
  • antagonism
  • biocontrol
  • genome-wide association study
  • phytopathogenic nematodes
  • plant growth
  • wheat

PubMed: MeSH publication types

  • Journal Article

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