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Edible mushrooms are important nutraceutical sources of foods and drugs, which can produce various nutritional ingredients including all essential amino acids. The method of rapid screening for the strains producing specific functional components is very indispensable. Homocitrate synthase is one of the key enzymes in the α-aminoadipate pathway for lysine biosynthesis and has preferable sequence conservation in Agaricales. Based on the blast of homocitrate synthase homologous genes of strains of Agaricales, we achieved combinations of degenerate primers as molecular markers to rapidly screen the lysine-producing edible mushrooms. The experimental results revealed that the consistency between PCR amplification and HPLC analysis attained 82 and 75% in strains of Agaricales and Polyporales, respectively. The finding showed that the molecular marker has higher universality for screening edible mushroom resources of Agaricales. This PCR-based approach shows excellent potential in evaluating and discriminating edible wild-grown mushrooms with high lysine content in Agaricales.

Siderophores are small molecular iron chelators and participate in the multiple cellular processes in fungi. In this study, we discovered and identified five amphiphilic coprogen siderophores including three new natural products according to LC-MS-guided separation strategy from Trichoderm hypoxylon. The structures of three new coprogens were elucidated by NMR spectroscopy, and high-resolution (HR)-ESI-MS analysis. Genetic deletions of dfcA and dfcB abolished the production of compounds 1-5 that implied their involvement in the biosynthesis of coprogens. Interestingly, cultivations of ΔdfcA and ΔdfcB mutants with pathogenic fungi Fusarium oxysporum and Mucor corcinelloides showed the weaker inhibitions in comparison to wild type that demonstrated coprogen's role in combating the pathogenic fungi. Our study not only enriched the diversities of siderophores but also provided an approach for finding the rare amphiphilic coprogen siderophores in fungi. Furthermore, this work provided a basis for investigation on the biosynthesis of fungal amphiphilic siderophores and their ecological roles in nature. KEY POINTS: • A series of amphiphilic coprogens were found. • The gene cluster of amphiphilic coprogens and ecological roles were elucidated.

Fungal secondary metabolites play an important role in the biological control of pests. The secondary metabolites produced by fungi, which are the main substance in biocontrol, have attracted more and more attention. With the development of sequencing technology in recent years, the use of genomic and bioinformatics technology to excavate fungal secondary metabolites has become a new hot spot, which also provide new strategies for the discovery of new fungal biocontrol agents in the post-genomic era. In this review, several typical insecticidal fungi and their invasion and pathogenic mechanisms were presented. Typically, insecticidal toxins produced by several common insecticidal fungi and the biosynthetic pathways were systematically summarized. Our review provides insights into the further development of fungal biocontrol agents. Finally, the application of fungal secondary metabolites in biocontrol agents was prospected.

Fungi from unique environments exhibit special physiological characters and plenty of bioactive natural products. However, the recalcitrant genetics or poor transformation efficiencies prevent scientists from systematically studying molecular biological mechanisms and exploiting their metabolites. In this study, we targeted a guanophilic fungus Amphichorda guana LC5815 and developed a genetic transformation system. We firstly established an efficient protoplast preparing method by conditional optimization of sporulation and protoplast regeneration. The regeneration rate of the protoplast is up to about 34.6% with 0.8 M sucrose as the osmotic pressure stabilizer. To develop the genetic transformation, we used the polyethylene glycol-mediated protoplast transformation, and the testing gene AG04914 encoding a major facilitator superfamily transporter was deleted in strain LC5815, which proves the feasibility of this genetic manipulation system. Furthermore, a uridine/uracil auxotrophic strain was created by using a positive screening protocol with 5-fluoroorotic acid as a selective reagent. Finally, the genetic transformation system was successfully established in the guanophilic fungus strain LC5815, which lays the foundation for the molecular genetics research and will facilitate the exploitation of bioactive secondary metabolites in fungi.