echemi logo
Product
  • Product
  • Supplier
  • Inquiry
    Home > Biochemistry News > Microbiology News > ​Nat Micro fungal spores have their own merits: Huang Guanhao's team discovered the internal mechanism of fungal spore heterogeneity with the same genetic background and its impact on fungal survival and environmental adaptability

    ​Nat Micro fungal spores have their own merits: Huang Guanhao's team discovered the internal mechanism of fungal spore heterogeneity with the same genetic background and its impact on fungal survival and environmental adaptability

    • Last Update: 2021-08-08
    • Source: Internet
    • Author: User
    Search more information of high quality chemicals, good prices and reliable suppliers, visit www.echemi.com

    Editor | Xi fungal infection is a fatal disease, and it has become a major clinical challenge in recent years
    .

    Generally speaking, fungal infections usually do not pose too much threat to healthy people, mainly affecting people or patients with weak immune systems
    .

    However, the pandemic of COVID19 has greatly increased the risk of fungal infection for everyone
    .

    In recent days, tens of thousands of COVID19 patients in India have been infected with "black, white, yellow and green fungi", making the pathogenic fungi become the current "accomplices" of COVID19
    .

    Therefore, fungal infection is very likely to make the global new crown epidemic worse
    .

    Conidia or Spores is the main way for pathogenic fungi to infect the host
    .

    They are the main germ cells for fungi to reproduce and spread, and each fungus growth colony can produce thousands of spores
    .

    Therefore, conidia exist in high density in the air
    .

    According to statistics, tens of thousands of spores can be detected per cubic meter, and we may inhale hundreds to thousands of spores every day
    .

    Under normal circumstances, these spores are cleared by macrophages in the human alveoli, but when the host's immune system is low, these "opportunists" can cause the patient to develop symptoms of fungal infection
    .

    Therefore, it is particularly important to understand how conidia are produced and the mechanisms related to their germination
    .

    The entire biological process of spores is strictly regulated from its production, maturation to dormancy
    .

    Spores have a strong ability to resist the external environment, while dormant conidia can survive for several years and decades
    .

    Interestingly, multiple studies have found that in many different fungi, spores of the same genetic background can show heterogeneity
    .

    Although there have been related reports decades ago, the mechanism has not been clear
    .

    Recent studies have found that there is a large amount of stable mRNA in dormant fungal spores
    .

    But how are these mRNAs produced? What is the function of these mRNAs? In this field, it is generally believed that the mRNA of dormant spores is transmitted from the parent cell (Conidiophore) during asexual reproduction
    .

    However, this idea has never been directly confirmed by experiments
    .

    This not only aroused the curiosity of the author of the study, but also caused other questions.
    Is the spore really dormant? If so, when and how was the dormant state established? On June 28, 2021, Chris Wong's group from the Faculty of Health Sciences of the University of Macau published an article Transcription in fungal conidia before dormancy produces phenotypically variable conidia that maximize survival in different environments in Nature Microbiology, and found that fungal spores of the same genetic background are different The qualitative internal mechanism and its influence on the survival and environmental adaptability of fungi reveal the profound significance of transcriptional activity on the adaptation of spores to their living environment and even the host environment they infect
    .

    Faced with the above-mentioned unresolved issues, the author of the study hypothesized that if the spores are really dormant or the mRNA is really passed from the parent cell (Conidiophore) during asexual reproduction, the spores will not have any transcriptional activity
    .

    Based on this, the study used immunoprecipitation combined with high-throughput sequencing technology (ChIPseq) to monitor the mold filamentous fungi Aspergillus nidulans and the pathogenic fungi Aspergillus fumigatus and Marneffei basket in real time.
    The transcription status of conidia on the mother cell of Talaromyces marneffei (including RNA polymerase I, II and III)
    .

    Surprisingly, spores have extremely active transcriptional activity
    .

    This unexpected result not only means that the spores can synthesize its own mRNAs, tRNAs and rRNAs, but also means that the spores that have not been separated from the mother cell are still active (that is, they are not dormant)
    .

    This important discovery broke the long-standing cognition in this field and played a paradigm shift in the understanding of spores
    .

    Not only that, the authors of the study also found that spores grown in different environments would transcribe different genes
    .

    More importantly, the spores can transcribe and express the corresponding response genes in real time according to environmental changes (such as temperature changes), and do not enter a dormant state until the spores leave their parent cells
    .

    Transcription is a highly energy-intensive process
    .

    The results of this study show that as the spores stay in the mother cell longer, the ATP in the body gradually decreases until ATP drops to zero (the spores that stay on the mother cell for about 40-50 days), and at the same time cause the loss of spores.
    Germination growth activity
    .

    "Why does the spore risk "death" and spend so much time to synthesize so many different mRNAs?" Wang Fang, the author of the study, asked
    .

    In this regard, the author hypothesized that the mRNA expressed by the spore may have a great help and influence on the growth of the spore itself or after the spore breaks dormancy
    .

    After a series of different experiments, it not only proved this hypothesis, but also found that two types of mRNA exist in the spores: one type is used to express proteins in the spore, and plays a role in the spore's own protein composition, cell structure, and synthesis of secondary metabolites.
    The other type is used for protein expression after spores break dormancy and germination (see schematic diagram)
    .

    In addition, the study further revealed that the mRNA expressed by the spores has a significant effect on germination and later physiological functions, including resistance (drug resistance and stress resistance), synthesis and secretion of secondary metabolites, and cytotoxicity
    .

    It is worth emphasizing that the mRNA in the spores can affect the development of fungal secondary metabolites, aspergillin (the second precursor of the strong carcinogen aflatoxin synthesis) and collomycin (a toxin that affects mycotoxicity) in Aspergillus spores.
    Production at the later stage of growth
    .

    These findings prove that the mRNA in the spore has a previously unknown or unimaginable importance
    .

    The real-time transcription of fungal spores and the regulation mechanism mode of the transcription process on the physiological functions of the spore itself, germination and later growth (picture from Nature Microbiology article Figure 6)
    .

    This study is not only the first to provide direct evidence to confirm the transcriptional activity in spores, but also reveals the profound significance of transcriptional activity for spores to adapt to their living environment and even to the host environment in which they infect
    .

    Based on the research findings, the spores are fully prepared to deal with the changing natural environment (see the cartoon picture) before dormancy, so as to obtain the precise competitive advantage of "winning at the starting line" in the environment of "competing for superiority".
    Achieve the purpose of "learning and excellence will become official"
    .

    A cartoon sketch of fungal spores fully prepared for the changing natural environment during development (through real-time transcription) (picture provided by the research team, painting by Lin Xinying, Samantha Lim) Finally, it is worth noting that the findings of this study are not only for the laboratory The growth conditions of spores in basic research put forward standard requirements, and also provide a solid theoretical and experimental basis for how to optimize bacterial strains in industrial breeding.
    At the same time, it also emphasizes the complexity of clinical fungal infection treatment
    .

    Nowadays, aspergillus caused by the pathogenic fungus A.
    fumigatus is threatening many patients with COVID19 pneumonia around the world, and T.
    marneffei is a specific cause in Southeast Asian countries including China.
    The "culprit" of Marneffe disease infection
    .

    Therefore, the research has more prominent and vital practical significance and application value in the context of this special new coronary pneumonia epidemic
    .

    Wang Fang, a doctoral student at the Faculty of Health Sciences at the University of Macau, is the first author of the paper, and Huang Guanhao, an associate professor at the Faculty of Health Sciences at the University of Macau, is the corresponding author of the paper
    .

    Doctoral students Pooja Sethiya, Guo Shuhui and Li Ang, as well as postdoctoral fellows Hu Xiaohui, Chen Yingying, and teacher Kaeling Tan participated in the research
    .

    Original link: https://doi.
    org/10.
    1038/s41564-021-00922-y Plate maker: Notes for reprinting on the 11th [Non-original article] The copyright of this article belongs to the author of the article.
    Personal forwarding and sharing are welcome.
    Reprinting is prohibited without permission.
    The author has all legal rights, and offenders must be investigated
    .


    This article is an English version of an article which is originally in the Chinese language on echemi.com and is provided for information purposes only. This website makes no representation or warranty of any kind, either expressed or implied, as to the accuracy, completeness ownership or reliability of the article or any translations thereof. If you have any concerns or complaints relating to the article, please send an email, providing a detailed description of the concern or complaint, to service@echemi.com. A staff member will contact you within 5 working days. Once verified, infringing content will be removed immediately.

    Contact Us

    The source of this page with content of products and services is from Internet, which doesn't represent ECHEMI's opinion. If you have any queries, please write to service@echemi.com. It will be replied within 5 days.

    Moreover, if you find any instances of plagiarism from the page, please send email to service@echemi.com with relevant evidence.