Paecilomyces maximusDPA synthase gene, pmdpa, is involved in colonization and biocontrol efficacy against soybean anthracnose

Abstract

AbstractBACKGROUNDPaecilomyces is emerging as an efficient biocontrol agent owing to its rapid growth, high sporulation capacity, and ability to compete for space and nutrients with fungal pathogens. Recently, Paecilomyces maximus spores were reported to contain dipicolinic acid (DPA), which was identified as a key component involved in P. maximus spore resistance to environmental stresses. DPA was found to be synthesized by the first DPA synthase (PmDpa) reported in fungi.RESULTSHere, the role of the pmdpa gene in P. maximus colonization and biocontrol ability was analyzed by comparing the biocontrol properties of wild‐type P. maximus NJC01 and knock‐out mutant Δpmdpa. NJC01 and Δpmdpa reduced Colletotrichum brevisporum mycelial growth by 48.1% and 34.2%, respectively. Δpmdpa showed 37.8%–56.9% lower colonization ability on soybean pods compared to NJC01. The ability of NJC01 to compete for space and nutrients with C. brevisporum was higher than that of Δpmdpa. In preventive application, 1 × 108 NJC01 spores mL−1 reduced anthracnose symptoms on soybean pods by 42.2–42.5% after 10 days. However, 1 × 108 Δpmdpa spores mL−1 reduced the disease symptoms by only 27.8%. The original phenotypes were recovered when using the complemented strain, Δpmdpa/pmdpa. Interestingly, combination of 1 × 108 NJC01 spores mL−1 and 0.02 mg mL−1 DPA promoted colony formation, and increased NJC01 preventive and curative efficacies up to 49.2% and 42.5%, respectively.CONCLUSIONSpmdpa was found to play a key role in P. maximus colonization and growth, revealing the first key factor involved in Paecilomyces biocontrol properties. © 2025 Society of Chemical Industry.