Sporulation environment drives phenotypic variation in the pathogenAspergillus fumigatus

Abstract

8Aspergillus fumigatus causes more than 300,000 life-threatening infections annually and is widespread across 9 varied environments with a single colony producing thousands of conidia, genetically-identical dormant spores. 10 Conidia are easily wind-dispersed to new environments where they can germinate and, if inhaled by susceptible 11 hosts, cause disease. Using high-throughput, single-cell analysis we show that germination phenotypes vary 12 among genetically-identical individuals and that the environment of spore production determines the degree of 13 germination heterogeneity. 15Fungal diseases kill over 1.5 million people each year 1, 2 . Rather than spreading patient-to-patient, fungal diseases 16 are acquired from the environment or normal flora. Nine of the ten most common agents of fungal disease can be 17 spread via spores 2, 3 . Breaking dormancy, or germinating, is arguably the most important step in pathogenesis for 18 these fungi. Historically studies have focused on the germination environment, addressing factors such as 19 temperature, inoculum density, carbon source, nitrogen source, and pH 4-8 . However, despite the wide range of 20 environments in which fungal spores are produced and their importance as disease agents, the impact of 21 sporulation environment on germination has been largely ignored. We hypothesized that exposure to specific 22 Dormant conidia produced in all sporulation environments showed very similar forward scatter profiles except for 40 conidia produced at 50C, in which the forward scatter peak shifted slightly to the right, suggesting a larger size. 41 Microscopic examination showed that conidia produced at 37°C were approximately 2-3 µm in diameter, while 42 those produced at 50°C were approximately 1.5 times larger ( Supplementary Fig. 2). 43 44 Not surprisingly, the rate at which conidia broke dormancy and grew varied depending on germination conditions. 45 Conidia germinated in standard media containing sufficient metals (CM, MM) at optimal temperature (37C) 46 showed larger median forward scatter values than conidia germinated in media with metal limitation (-Zn, -Fe), at 47 d Pearson correlation analysis between median forward scatter and observed variation (rCV) within a germination group. r = 62 correlation coefficient.63 e The Kruskall-Wallis test determines whether there is a difference in distribution between multiple groups and is performed on 64 ranked data. H = the Kruskall-Wallis statistic, an indication of the difference between groups; df = degrees of freedom. The p 65 values indicate significance of differences among sporulation environments in the germination condition.66 f Mean rank from Kruskal-Wallis test indicates which sporulation conditions tend to have the greatest values in the germination 67 group.68 g Dunn's multiple comparison test. Mean rank for each sporulation environment in the same germination condition was 69compared to the mean rank of the same sporulation and germination conditions. Dunn's test compares the diff...

Transcriptional reprogramming in the entomopathogenic fungus Metarhizium brunneum and its aphid host Myzus persicae during the switch between saprophytic and parasitic lifestyles

“…9). Our data suggest that conidia prepare for the sensed environment, in agreement with previous studies (Earl Kang et al, 2021;Hagiwara et al, 2017;Krach et al, 2022). Interestingly, conidia begin to express genes and store mRNA needed for subsequent growth in the sensed environment even before detachment from the conidiophore or dormancy (Wang et al, 2021).…”

Biotinylated Surfome Profiling Identifies Potential Biomarkers for Diagnosis and Therapy of Aspergillus fumigatus Infection

“…As published in our previous studies, the dynamic surfome of A. fumigatus is affected by various cultivation conditions, including the medium, temperature, and time, and contains many proteins secreted by nonclassical pathways ( 10 , 11 ). Correspondingly, a recent study also revealed that the phenotypes of A. fumigatus germinating conidia vary among genetically identical conidia ( 66 ). Here, we detected 61, 69, and 85 proteins on dormant, swollen, and germinating conidia, respectively; while 136 proteins were found on the surface of hyphae ( Fig.…”

Identifying Conserved Generic Aspergillus spp. Co-Expressed Gene Modules Associated with Germination Using Cross-Platform and Cross-Species Transcriptomics

“…Additionally, experimental conditions of both studies were different, such as the pre-culture medium and germination medium. Nutritional environment during sporulation, as well as during germination, affects the rate of the breaking of dormancy and growth in A. fumigatus [85]. A. fumigatus strains were cultivated on Sabouraud agar slants (dextrose 40 g/L, peptone 10 g/L, agar 20 g/L, pH = 5.6) for five days at 30 • C, and A. niger was cultivated on complete medium (CM) (1.5% agar, 6.0 g NaNO3, 1.5 g KH2PO4, 0.5 g KCl, 0.5 g MgSO4, 4.5 g D-glucose, 0.5% casamino acids, 1% yeast extract, and 200 µL trace elements per liter) for 12 days at 25 • C. RNA was extracted after growth in liquid RPMI 1640 (Gibco ® life technologies) and liquid CM for A. fumigatus and A. niger, respectively.…”