scholarly journals UvWHI2 is Required for Stress Response and Pathogenicity in Ustilaginonidea Virens

2020 ◽  
Author(s):  
Shuai Meng ◽  
Jiehua Qiu ◽  
Meng Xiong ◽  
Zhiquan Liu ◽  
Jane Sadhna Jagernath ◽  
...  
Keyword(s):  
Stress Response ◽  
Stress Responses ◽  
Fungal Growth ◽  
Growth Stress ◽  
Phenotypic Analysis ◽  
Ustilaginoidea Virens ◽  
General Stress Response ◽  
Relative Expression Level ◽  
False Smut ◽  
Limited Surface

Abstract Background: Ustilaginoidea virens causes rice false smut disease, which emerges as a worldwide disease of rice. At present, some stress response related genes have been identified in U. virens , but it is not clear whether and how defects of stress responses affect the pathogenesis processes of U. virens . To answer this question, the function of a general stress response factor Whi2 was analyzed in U. virens . Results: In this study, we identified UvWhi2 as a homolog of Saccharomyces cerevisiae Whi2 in U. virens. The relative expression level of UvWhi2 was significantly up-regulated during infection, suggesting that UvWhi2 may be involved in pathogenesis. Furthermore, knockout of UvWhi2 showed decreased the mycelial growth, increased in conidiation in the PS (potato sucrose) medium and a defect in pathogenicity. In addition, the RNA-Seq and phenotypic analysis showed that UvWHI2 is involved in response to oxidative, hyperosmotic, cell wall stresses, and nutrient limitation. Further studies revealed that the defects of stress responses of the ∆ Uvwhi2 mutant affected the formation of secondary spores on the nutrient limited surface and the rice surface, resulting in a significant reduction of pathogenicity of U. virens . Conclusions: Our results suggest that UvWhi2 is necessary for fungal growth, stress responses, and the formation of secondary spores in U. virens . In addition, the defects of stress responses could affect the formation of secondary spores on the rice surface, and then compromise the pathogenicity of U. virens .

scholarly journals UvAtg8-Mediated Autophagy Regulates Fungal Growth, Stress Responses, Conidiation, and Pathogenesis in Ustilaginoidea virens

Rice ◽  
2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Shuai Meng ◽  
Meng Xiong ◽  
Jane Sadhna Jagernath ◽  
Congcong Wang ◽  
Jiehua Qiu ◽  
...  
Keyword(s):  
Stress Responses ◽  
Fungal Growth ◽  
Growth Stress ◽  
Ustilaginoidea Virens

scholarly journals Structure-guided approaches to targeting stress responses in human fungal pathogens

2020 ◽  
Vol 295 (42) ◽  
pp. 14458-14472
Author(s):  
Emmanuelle V. LeBlanc ◽  
Elizabeth J. Polvi ◽  
Amanda O. Veri ◽  
Gilbert G. Privé ◽  
Leah E. Cowen
Keyword(s):  
Stress Response ◽  
Stress Responses ◽  
Fungal Pathogens ◽  
Fungal Infections ◽  
Fungal Growth ◽  
Small Gtpase ◽  
Ecological Niches ◽  
Attractive Alternative ◽  
Response Regulators ◽  
Fungal Virulence

Fungi inhabit extraordinarily diverse ecological niches, including the human body. Invasive fungal infections have a devastating impact on human health worldwide, killing ∼1.5 million individuals annually. The majority of these deaths are attributable to species of Candida, Cryptococcus, and Aspergillus. Treating fungal infections is challenging, in part due to the emergence of resistance to our limited arsenal of antifungal agents, necessitating the development of novel therapeutic options. Whereas conventional antifungal strategies target proteins or cellular components essential for fungal growth, an attractive alternative strategy involves targeting proteins that regulate fungal virulence or antifungal drug resistance, such as regulators of fungal stress responses. Stress response networks enable fungi to adapt, grow, and cause disease in humans and include regulators that are highly conserved across eukaryotes as well as those that are fungal-specific. This review highlights recent developments in elucidating crystal structures of fungal stress response regulators and emphasizes how this knowledge can guide the design of fungal-selective inhibitors. We focus on the progress that has been made with highly conserved regulators, including the molecular chaperone Hsp90, the protein phosphatase calcineurin, and the small GTPase Ras1, as well as with divergent stress response regulators, including the cell wall kinase Yck2 and trehalose synthases. Exploring structures of these important fungal stress regulators will accelerate the design of selective antifungals that can be deployed to combat life-threatening fungal diseases.

scholarly journals SUN-Family Protein UvSUN1 Regulates the Development and Virulence of Ustilaginoidea virens

2021 ◽  
Vol 12 ◽  
Author(s):  
Mina Yu ◽  
Junjie Yu ◽  
Huijuan Cao ◽  
Tianqiao Song ◽  
Xiayan Pan ◽  
...  
Keyword(s):  
Cell Wall ◽  
Hyphal Growth ◽  
Cell Wall Integrity ◽  
Signal Recognition ◽  
Phenotypic Analysis ◽  
Ustilaginoidea Virens ◽  
Group I ◽  
Family Protein ◽  
False Smut

Ustilaginoidea virens, the causal agent of rice false smut disease, is an important plant pathogen that causes severe quantitative and qualitative losses in rice worldwide. UvSUN1 is the only member of Group-I SUN family proteins in U. virens. In this work, the role of UvSUN1 in different aspects of the U. virens biology was studied by phenotypic analysis of Uvsun1 knockout strains. We identified that UvSUN1 was expressed during both conidial germination and the infection of rice. Disruption of the Uvsun1 gene affected the hyphal growth, conidiation, morphology of hyphae and conidia, adhesion and virulence. We also found that UvSUN1 is involved in the production of toxic compounds, which are able to inhibit elongation of the germinated seeds. Moreover, RNA-seq data showed that knockout of Uvsun1 resulted in misregulation of a subset of genes involved in signal recognition and transduction system, glycometabolism, cell wall integrity, and secondary metabolism. Collectively, this study reveals that Uvsun1 is required for growth, cell wall integrity and pathogenicity of U. virens, thereby providing new insights into the function of SUN family proteins in the growth and pathogenesis of this pathogen.

scholarly journals PhyR Is Involved in the General Stress Response of Methylobacterium extorquens AM1

2007 ◽  
Vol 190 (3) ◽  
pp. 1027-1035 ◽  
Author(s):  
Benjamin Gourion ◽  
Anne Francez-Charlot ◽  
Julia A. Vorholt
Keyword(s):  
Stress Response ◽  
Heat Shock ◽  
Stress Responses ◽  
Target Genes ◽  
Stress Proteins ◽  
Plant Colonization ◽  
Methylobacterium Extorquens ◽  
General Stress Response ◽  
Amino Terminal ◽  
General Stress

ABSTRACTPhyR represents a novel alphaproteobacterial family of response regulators having a structure consisting of two domains; a predicted amino-terminal extracytoplasmic function (ECF) sigma factor-like domain and a carboxy-terminal receiver domain. PhyR was first described inMethylobacterium extorquensAM1, in which it has been shown to be essential for plant colonization, probably due to its suggested involvement in the regulation of a number of stress proteins. Here we investigated the PhyR regulon using microarray technology. We found that the PhyR regulon is rather large and that most of the 246 targets are under positive control. Mapping of transcriptional start sites revealed candidate promoters for PhyR-mediated regulation. One of these promoters, an ECF-type promoter, was identified upstream of one-third of the target genes by in silico analysis. Among the PhyR targets are genes predicted to be involved in multiple stress responses, includingkatE,osmC,htrA,dnaK,gloA,dps, anduvrA. The induction of these genes is consistent with our phenotypic analyses which revealed that PhyR is involved in resistance to heat shock and desiccation, as well as oxidative, UV, ethanol, and osmotic stresses, inM. extorquensAM1. The finding that PhyR is involved in the general stress response was further substantiated by the finding that carbon starvation induces protection against heat shock and that this protection is at least in part dependent on PhyR.

scholarly journals Global Transcriptional Response of Bacillus subtilis to Heat Shock

2001 ◽  
Vol 183 (24) ◽  
pp. 7318-7328 ◽  
Author(s):  
John D. Helmann ◽  
Ming Fang Winston Wu ◽  
Phil A. Kobel ◽  
Francisco-Javier Gamo ◽  
Michael Wilson ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Stress Response ◽  
Heat Shock ◽  
Dna Sequences ◽  
Stress Responses ◽  
Transcriptional Response ◽  
Transcriptional Responses ◽  
General Stress Response ◽  
General Stress ◽  
Induced Genes

ABSTRACT In response to heat stress, Bacillus subtilisactivates the transcription of well over 100 different genes. Many of these genes are members of a general stress response regulon controlled by the secondary sigma factor, ςB, while others are under control of the HrcA or CtsR heat shock regulators. We have used DNA microarrays to monitor the global transcriptional response to heat shock. We find strong induction of known ςB-dependent genes with a characteristic rapid induction followed by a return to near prestimulus levels. The HrcA and CtsR regulons are also induced, but with somewhat slower kinetics. Analysis of DNA sequences proximal to newly identified heat-induced genes leads us to propose ∼70 additional members of the ςB regulon. We have also identified numerous heat-induced genes that are not members of known heat shock regulons. Notably, we observe very strong induction of arginine biosynthesis and transport operons. Induction of several genes was confirmed by quantitative reverse transcriptase PCR. In addition, the transcriptional responses measured by microarray hybridization compare favorably with the numerous previous studies of heat shock in this organism. Since many different conditions elicit both specific and general stress responses, knowledge of the heat-induced general stress response reported here will be helpful for interpreting future microarray studies of other stress responses.

scholarly journals Extracytoplasmic Function σ Factors as Tools for Coordinating Stress Responses

2021 ◽  
Vol 22 (8) ◽  
pp. 3900
Author(s):  
Rubén de de Dios ◽  
Eduardo Santero ◽  
Francisca Reyes-Ramírez
Keyword(s):  
Gene Expression ◽  
Escherichia Coli ◽  
Stress Response ◽  
Stress Responses ◽  
Transcription Initiation ◽  
Genomic Context ◽  
General Stress Response ◽  
Functional Studies ◽  
Functional Stress

The ability of bacterial core RNA polymerase (RNAP) to interact with different σ factors, thereby forming a variety of holoenzymes with different specificities, represents a powerful tool to coordinately reprogram gene expression. Extracytoplasmic function σ factors (ECFs), which are the largest and most diverse family of alternative σ factors, frequently participate in stress responses. The classification of ECFs in 157 different groups according to their phylogenetic relationships and genomic context has revealed their diversity. Here, we have clustered 55 ECF groups with experimentally studied representatives into two broad classes of stress responses. The remaining 102 groups still lack any mechanistic or functional insight, representing a myriad of systems yet to explore. In this work, we review the main features of ECFs and discuss the different mechanisms controlling their production and activity, and how they lead to a functional stress response. Finally, we focus in more detail on two well-characterized ECFs, for which the mechanisms to detect and respond to stress are complex and completely different: Escherichia coli RpoE, which is the best characterized ECF and whose structural and functional studies have provided key insights into the transcription initiation by ECF-RNAP holoenzymes, and the ECF15-type EcfG, the master regulator of the general stress response in Alphaproteobacteria.

General Stress Response Regulator RpoS in Adaptive Mutation and Amplification in Escherichia coli

Genetics ◽  
2004 ◽  
Vol 166 (2) ◽  
pp. 669-680 ◽  
Author(s):  
Mary-Jane Lombardo ◽  
Ildiko Aponyi ◽  
Susan M Rosenberg
Keyword(s):  
Escherichia Coli ◽  
Stress Response ◽  
Stationary Phase ◽  
Point Mutation ◽  
Stress Responses ◽  
Genome Rearrangement ◽  
Adaptive Mutation ◽  
Induced Mutations ◽  
General Stress Response ◽  
General Stress

Abstract Microbial cells under growth-limiting stress can generate mutations by mechanisms distinct from those in rapidly growing cells. These mechanisms might be specific stress responses that increase mutation rates, potentially altering rates of evolution, or might reflect non-stress-specific processes in rare growing cells. In an Escherichia coli model system, both frameshift reversion mutations and gene amplifications occur as apparent starvation-induced mutations. Whereas frameshift reversion (“point mutation”) requires recombination proteins, the SOS response, and error-prone DNA polymerase IV (DinB), amplification requires neither SOS nor pol IV. We report that both point mutation and amplification require the stationary-phase and general stress response transcription factor RpoS (σS). Growth-dependent mutation does not. Alternative interpretations are excluded. The results imply, first, that point mutation and amplification are stress responses that occur in differentiated stationary-phase (not rare growing) cells and, second, that transient genetic instability, producing both point mutation and genome rearrangement, may be a previously unrecognized component of the RpoS-dependent general stress response.

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