Characterization of Vegetative Incompatibility in Morchella importuna and Location of the Related-Genes by Bulk Segregant Analysis

Antimicrobial Activity of Three Italian Strains of Morchella esculenta (Ascomycota)

Three genetically identified and morphologically characterized strains (MesAQ2-C, MesAQ6-2 and MesFI2-3) of the culinary-medicinal ascomycete mushroom Morchella esculenta (L.) Pers. collected in central-north Italy have been studied for their antifungal and antibacterial activities. The obtained data showed that mycelium of M. esculenta possess variable antimicrobial activity against four test fungi (Chrysosporium keratinophilum, Microsporum gypseum, Trichophyton terrestre, Penicillium griseofulvum), as well as one Gram positive (Staphylococcus aureus) and three Gram negative (Escherichia coli, Salmonella typhimurium, Pseudomonas aeruginosa) test bacteria potentially pathogenic for humans and animals. Up to 20.4% of inhibition of the average mycelial growth rate (GRavr) of test fungi in dual culture experiment was detected. The samples of cultural liquid (CL) and mycelial extract (ME) obtained by static cultivation of M. esculenta strains showed up to 13.9 and 23.0% of GRavr inhibition of test fungi, respectively. Similarly, the inhibition of the bacterial colonies by CL and ME samples was 34.1 and 32.3%, respectively in comparison with the control with streptomycin indicating almost equal secretion of both intra- and extracellular antimicrobial compounds by M. esculenta mycelium. As a producer of antimicrobial compounds among tested M. esculenta strains, MesAQ2-C was the most effective. It may be considered for further myco-pharmacological research to develop mushroom-based antimicrobial biotech products with biomedical significance.

Construction of nucleus-directed fluorescent reporter systems and its application to verification of heterokaryon formation in Morchella importuna

INTRODUCTION

Morchella importuna (M. importuna) is a rare fungus with high nutrition value and distinct flavor. Despite the successful artificial cultivation, its genetic characteristics and biological processes such as life cycle, reproductive system, and trophic mode remain poorly understood.

METHODS

Considering this, we constructed pEH2B and pMH2B vectors by fusing M. importuna endogenous histone protein H2B with fluorescent proteins eGFP or mCherry, respectively. Based on the constructed pEH2B and pMH2B vectors, nuclear fluorescence localization was performed via Agrobacterium tumefaciens-mediated transformation (ATMT). These two vectors were both driven by two endogenous promoters glyceraldehyde 3-phosphate dehydrogenase (GPD) and ubiquitin (UBI). The vector-based reporter systems were tested by the paired culture of two genetically modified strains pEH2B-labeled M04M24 (24e, MAT1-1-1) and pMH2B-abeled M04M26 (26m, MAT1-2-1).

RESULTS

The fluorescence observation and molecular identification results indicated the successful hyphal fusion and heterokaryon formation. We found that the expression of the reporter genes was stable, and it did not interfere with the growth of the fungus.

DISCUSSION

Our constructed nucleus-directed fluorescent systems in M. importuna can be used for monitoring the dynamic development and reproductive processes in living cells and also for monitoring the interaction between morels and plant roots. Therefore, morels exhibit the potential to be a candidate organism used for the research on basic biology and genetics of ascomycetes.