Search

In order to improve the safety and preservability of fermented vegetables, strain Leuconostoc mesenteroides AP7, with potent inhibitory effects on foodborne pathogens and bacteria causing paocai over-acidification, was selected from 8 Leuconostoc strains derived from traditional fermented vegetables in Yunnan, China. The main antimicrobial substance of AP7 was determined by eliminating the effects of organic acid and H2O2 and through protease sensitivity. The acid stability and thermal stability were analyzed and potential bacteriocin gene clusters were mined from the whole genome sequence of AP7. The results showed that the culture supernatant still had obvious antibacterial activity after excluding the influence of acid and H2O2, and after protease treatment, the antibacterial effect decreased significantly. It was speculated that the antibacterial substance in the concentrated culture supernatant was bacteriocin. The bacteriocin was sensitive to pH changes, had high thermal stability, and had a molecular weight of 6.51~14.4 kDa. Whole genome sequencing showed that the whole genome of AP7 contained 1 chromosome (1948310 bp) and 2 plasmids (37366 and 20698 bp), with a GC content of 37.7%. There was a gene cluster with Enterocin_X_chain_beta bacteriocin as the core. Its encoded product was predicted to be a positively charged hydrophilic stable protein, the secondary structure was dominated by a-helix, and the tertiary structure was mainly composed of loose peptide chains at both ends and an α-helix in the middle. In summary, the bacteriocin-producing Leuconostoc mesenteroides AP7 has excellent antibacterial properties and has the potential to be applied to the fermentation and preservation of acidic foods. [ABSTRACT FROM AUTHOR]

Verpa spp. are potentially important economic fungi within Morchellaceae. However, fundamental research on their mating systems, the key aspects of their life cycle, remains scarce. Fungal sexual reproduction is chiefly governed by mating-type genes, where the configuration of these genes plays a pivotal role in facilitating the reproductive process. For this study, de novo assembly methodologies based on genomic data from Verpa spp. were employed to extract precise information on the mating-type genes, which were then precisely identified in silico and by amplifying their single-ascospore populations using MAT-specific primers. The results suggest that the MAT loci of the three tested strains of V. bohemica encompassed both the MAT1-1-1 and MAT1-2-1 genes, implying homothallism. On the other hand, amongst the three V. conica isolates, only the MAT1-1-1 or MAT1-2-1 genes were present in their MAT loci, suggesting that V. conica is heterothallic. Moreover, bioinformatic analysis reveals that the three tested V. bohemica strains and one V. conica No. 21110 strain include a MAT1-1-10 gene in their MAT loci, while the other two V. conica strains contained MAT1-1-11, exhibiting high amino acid identities with those from corresponding Morchella species. In addition, MEME analysis shows that a total of 17 conserved protein motifs are present among the MAT1-1-10 encoded protein, while the MAT1-1-11 protein contained 10. Finally, the mating type genes were successfully amplified in corresponding single-ascospore populations of V. bohemica and V. conica, further confirming their life-cycle type. This is the first report on the mating-type genes and mating systems of Verpa spp., and the presented results are expected to benefit further exploitation of these potentially important economic fungi. [ABSTRACT FROM AUTHOR]

Morchella mushrooms are edible and medicinal mushrooms appreciated worldwide. Since 2012, the scale of morel artificial cultivation has been increasing year after year in China. However, the instability of morel cultivation has been frustrating morel farming. The industrial instability may be closely related to the imperfection of strain evaluation system of cultivating suitability and the resulted implication of poor quality and unstable spawns in practical cultivation. Compared with most mushrooms belonging to Basidiomycota, the ascomycetes of morels own special characteristics in species diversity, deletion of mating type genes, and rapid strain aging, which put forward special request for systematic detection of relevant characteristics in cultivated strains. Based on long-term fundamental research and practical experiences, an IMV evaluation system of cultivating suitability for productive strains of Morchella mushrooms, including identity recognition, detection of mating types and assay of vitality, was proposed in this paper. The technological necessity and the detailed procedure were sorted out. Given the application of the evaluation system in field cultivation in two seasons, the potential morel productive strains may be scientifically and systematically screened and assessed to confirm the use of suitable strains in cultivation, which will strengthen the stability of morel cultivation, and thus promote the sustainable and stable development of morel industry. [ABSTRACT FROM AUTHOR]

In March 2013, pileus rot disease was first observed on cultivated Morchella importuna. Infected ascomata were covered by white, velvety mycelia mainly on the pileus, and the infection resulted in malformed fruiting bodies. The causal pathogen was identified as Diploöspora longispora based on its morphology and the internal transcribed spacer of its ribosomal DNA sequences. After inoculation of young ascomata with the isolates, the original symptoms were reproduced, and the same pathogen was reisolated from diseased ascomata. This is the first report of pileus rot disease on morels caused by D. longisporain China. [ABSTRACT FROM AUTHOR]