Odeshnee Moodley

Morels ( Morchella spp.) are among the most widely cultivated edible mushrooms in China, but rapid expansion of production has been accompanied by rising incidence of white mold disease (WMD), reducing yields. Although more than 10 fungi have been reported associated with WMD, the diversity and distribution of causal agents remain unclear. In this study, 832 diseased fruiting bodies of Morchella importuna , M. sextelata , and M. septimelata were collected from 64 locations across 16 major morel-producing provinces in China. Sixty Clonostachys isolates were recovered and identified using morphological traits and multilocus phylogenetic analyses, confirming four species: C. chloroleuca , C. farinosa , C. rosea , and C. solani . Of these, C. chloroleuca and C. farinosa were reported for the first time on morels in China. Clonostachys rosea was dominant (81.7% of isolates), widely distributed, and induced mold symptoms in the pathogenicity test. In contrast, C. chloroleuca , C. farinosa , and C. solani showed comparatively lower frequencies and pathogenicity. These findings broaden the understanding of Clonostachys diversity associated with WMD and provide a foundation for developing integrated management strategies in commercial morel production.

White mold disease (WMD) is a major constraint to Morchella cultivation in China, leading to significant yield and quality losses. While Fusarium species are recognized plant pathogens, their diversity and role in WMD of morels have been poorly understood. This study aimed to identify and characterize Fusarium species associated with WMD in cultivated morels. Symptomatic ascocarps were collected from 22 cultivation bases across 16 provinces in China. A total of 120 Fusarium isolates were recovered and identified using morphological traits and multi-locus phylogenetic analysis. Twelve Fusarium species were identified, F. acuminatum, F. avenaceum, F. clavum, F. compactum, F. falciforme, F. flocciferum, F. ipomoeae, F. mucidum, F. oxysporum, F. proliferatum, F. subglutinans, and F. verticillioides, with most isolates recovered from northern China. Among them, F. verticillioides was the most common species (22.5%). Pathogenicity assays showed that all twelve of the identified Fusarium species were virulent to morel ascocarps. This is the first comprehensive report of these twelve Fusarium species causing WMD in morels, providing critical insights into pathogen diversity and virulence in Morchella production systems. These findings will support the development of targeted monitoring and management strategies to reduce the impact of WMD in morel cultivation.

The “replacing wood by grass” project can partially resolve the conflict between mushroom production and balancing the ecosystem, while promoting agricultural economic sustainability.Pleurotus pulmonariusis an economically important edible and medicinal mushroom, which is traditionally produced using a substrate consisting of sawdust and cottonseed hulls, supplemented with wheat bran. A simplex lattice design was applied to systemically optimize the cultivation ofP. pulmonariususing agro-residues as the main substrate to replace sawdust and cottonseed hulls. The effects of differing amounts of wheat straw, corn straw, and soybean straw on the variables of yield, mycelial growth rate, stipe length, pileus length, pileus width, and time to harvest were demonstrated. Results indicated that a mix of wheat straw, corn straw, and soybean straw may have significantly positive effects on each of these variables. The high yield comprehensive formula was then optimized to include 40.4% wheat straw, 20.3% corn straw, 18.3% soybean straw, combined with 20.0% wheat bran, and 1.0% light CaCO₃(C/N = 42.50). The biological efficiency was 15.2% greater than that of the control. Most encouraging was the indication that the high yield comprehensive formula may shorten the time to reach the reproductive stage by 6 days, compared with the control. Based on the results of this study, agro-residues may be used as a suitable substitution for sawdust and cottonseed hulls as the main cultivation substrates ofP. pulmonarius. These results provide a theoretical basis for the “replacing wood by grass” project on edible mushroom cultivation.

Two new species (Melanoleuca galerina and M. subgrammopodia) and seven new recorded species from northern China are described here using morphological and molecular methods. Melanoleuca galerina is mainly characterized by its hygrophanous pileus, decurrent lamellae, fibrous stipe and spores with round warts. Key characteristics of M. subgrammopodia include its discolored pileus, fibrous stipe and urticiform cystidia. The divergence time of Melanoleuca fungi as well as the phylogenetic relationships within this genus were analyzed using DNA sequences of the internal transcribed spacer (ITS) and the nuclear large subunit rDNA (nrLSU) gene fragments. Analyses revealed that morphological identifications and phylogenetic relationships were consistent with the results of divergence time, thereby confirming that M. galerina and M. subgrammopodia are new species.

Myxomycetes are eukaryotic microorganisms containing characteristics akin to both fungi and amoebae. They can complete their whole life cycles while being cultured on agar media, and under‐laboratory conditions, which favors taxonomic, phylogenetic, and cytological researches. Here, we describe the life cycles of two such species: Didymium squamulosum collected from the field and Physarum rigidum cultured from moist chamber both belonging to the Order Physarales. Three per cent oat‐agar media (OAM) was used to culture the plasmodia until they aggregated and were almost starved. Natural light was then applied to the plasmodia to induce fructification. Their life cycles share the same common stages, namely: spore, myxamoebae, swarm cell, plasmodia, and sporulation. In this study, we describe the morphogenesis from spore to spore of two species by differential interference contrast (DIC) and stereoscopic microscopies, as well as discuss the differences between the development of both species and interspecies. We found that the spore germination method of both species was the same. However, there were differences noted in time taken and fruiting body formation. Unlike P. rigidum, the species D. squamulosum did not require natural light stimulation. Moreover, the maturation process of both species had similar color transitions but exhibited distinct morphology in each developmental stage except during the swarm cell stage.

Ganoderma lingzhi, commonly known as the lingzhi mushroom, is frequently used in traditional Chinese medicine. Green mold on G. lingzhi is becoming a disease of concern in Jilin Province, China, but the causal agent is not yet known. Therefore, this study aimed to confirm both the causal pathogen by using Koch postulates and its identity by using morphological and molecular methods. The pathogen was identified as Trichoderma atroviride. Young basidiomes were inoculated with T. atroviride, which reproduced the original signs; the same pathogen was isolated again from diseased basidiomes. Green mold disease on G. lingzhi is reported here as a new fungal disease that is caused by T. atroviride in China.

Alternaria oxytropis is an endophytic fungus of locoweeds that synthesizes swainsonine toxin. In this work, we evaluated the effect of A. oxytropis on soybean seedlings and quantified swainsonine in different culture conditions. Soybean (Glycine max) seeds were co-cultured with A. oxytropis (at different concentrations of mycelial suspensions) in agar media and soil culture, and swainsonine was assayed using LC–MS/MS. The results showed evidence that A. oxytropis infected soybean seedlings produced detectable swainsonine in agar culture while the toxin was undetectable or below the detection limit (0.006% of swainsonine dry weight) in soil media even at higher concentrations of the fungus. These results suggest that swainsonine detection is highly dependent on culture conditions and that soybeans co-cultured with A. oxytropis in soil could potentially be used to limit toxin production.

Tricholosporum haitangshanum sp. nov. is described as a new species from China, based on morphological and molecular data. It is morphologically characterized by a yellowish ochre pileus, cruciate basidiospores and ampullaceous cystidia. Phylogenetic analyses based on the nuc rDNA internal transcribed spacer (ITS) region supports that it belongs to Tricholosporum. Comparing it with phenotypically similar and molecular phylogenetically allied taxa concluded that it is a new species in Tricholosporum.

A microcosm experiment was conducted to compare how different chelating agents enhance the phytoextraction of lead (Pb) by Mirabilis jalapa from an artificially Pb-contaminated soil. Chelating agents used included ethylene diamine tetraacetic acid (EDTA), nitrilotriacetic acid (NTA), ethylene diamine disuccinic acid (EDDS), oxalic acid, humic acid, citric acid and tartaric acid, with concentrations ranging from 0 to 2000 mg/kg. Results show that with increasing concentrations of chelating agents, the concentrations, bioaccumulation coefficients, and translocation factors of Pb in M. jalapa gradually increased. Of all chelating agents used, the concentrations, bioaccumulation coefficients and translocation factors of Pb in M. jalapa were higher for EDTA and NTA than for the other chelating agents. Given the potential environmental risks of EDTA, we recommend NTA be used as a suitable chelating agent to increase the phytoremediation of Pb-contaminated soil with M. jalapa.