Csp1, a Cold Shock Protein Homolog in Xylella fastidiosa Influences Cell Attachment, Pili Formation, and Gene Expression

ABSTRACT Bacterial cold shock-domain proteins are conserved nucleic acid binding chaperones that play important roles in stress adaptation and pathogenesis. Csp1 is a temperature-independent cold shock protein homolog in Xylella fastidiosa, a bacterial plant pathogen of grapevine and other economica...

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Main Authors: Wei Wei, Teresa Sawyer, Lindsey Burbank
Format: Article
Language:English
Published: American Society for Microbiology 2021-12-01
Series:Microbiology Spectrum
Subjects:
Online Access:https://journals.asm.org/doi/10.1128/Spectrum.01591-21
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author Wei Wei
Teresa Sawyer
Lindsey Burbank
author_facet Wei Wei
Teresa Sawyer
Lindsey Burbank
author_sort Wei Wei
collection DOAJ
description ABSTRACT Bacterial cold shock-domain proteins are conserved nucleic acid binding chaperones that play important roles in stress adaptation and pathogenesis. Csp1 is a temperature-independent cold shock protein homolog in Xylella fastidiosa, a bacterial plant pathogen of grapevine and other economically important crops. Csp1 contributes to stress tolerance and virulence in X. fastidiosa. However, besides general single-stranded nucleic acid binding activity, little is known about the specific function(s) of Csp1. To further investigate the role(s) of Csp1, we compared phenotypic differences and transcriptome profiles between the wild type and a csp1 deletion mutant (Δcsp1). Csp1 contributes to attachment and long-term survival and influences gene expression. We observed reduced cell-to-cell attachment and reduced attachment to surfaces with the Δcsp1 strain compared to those with the wild type. Transmission electron microscopy imaging revealed that Δcsp1 was deficient in pili formation compared to the wild type and complemented strains. The Δcsp1 strain also showed reduced survival after long-term growth in vitro. Long-read nanopore transcriptome sequencing (RNA-Seq) analysis revealed changes in expression of several genes important for attachment and biofilm formation in Δcsp1 compared to that in the wild type. One gene of interest, pilA1, which encodes a type IV pili subunit protein, was upregulated in Δcsp1. Deleting pilA1 in X. fastidiosa strain Stag’s Leap increased surface attachment in vitro and reduced virulence in grapevines. X. fastidiosa virulence depends on bacterial attachment to host tissue and movement within and between xylem vessels. Our results show that the impact of Csp1 on virulence may be due to changes in expression of attachment genes. IMPORTANCE Xylella fastidiosa is a major threat to the worldwide agriculture industry. Despite its global importance, many aspects of X. fastidiosa biology and pathogenicity are poorly understood. There are currently few effective solutions to suppress X. fastidiosa disease development or eliminate bacteria from infected plants. Recently, disease epidemics due to X. fastidiosa have greatly expanded, increasing the need for better disease prevention and control strategies. Our studies show a novel connection between cold shock protein Csp1 and pili abundance and attachment, which have not been reported for X. fastidiosa. Understanding how pathogenesis-related gene expression is regulated can aid in developing novel pathogen and disease control strategies. We also streamlined a bioinformatics protocol to process and analyze long-read nanopore bacterial RNA-Seq data, which will benefit the research community, particularly those working with non-model bacterial species.
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spelling doaj.art-d721c26655df4ca7993a0ce6e78a27e32022-12-22T04:15:50ZengAmerican Society for MicrobiologyMicrobiology Spectrum2165-04972021-12-019310.1128/Spectrum.01591-21Csp1, a Cold Shock Protein Homolog in Xylella fastidiosa Influences Cell Attachment, Pili Formation, and Gene ExpressionWei Wei0Teresa Sawyer1Lindsey Burbank2USDA Agricultural Research Service, San Joaquin Valley Agricultural Sciences Center, Parlier, California, USAElectron Microscopy Facility, Oregon State University, Corvallis, Oregon, USAUSDA Agricultural Research Service, San Joaquin Valley Agricultural Sciences Center, Parlier, California, USAABSTRACT Bacterial cold shock-domain proteins are conserved nucleic acid binding chaperones that play important roles in stress adaptation and pathogenesis. Csp1 is a temperature-independent cold shock protein homolog in Xylella fastidiosa, a bacterial plant pathogen of grapevine and other economically important crops. Csp1 contributes to stress tolerance and virulence in X. fastidiosa. However, besides general single-stranded nucleic acid binding activity, little is known about the specific function(s) of Csp1. To further investigate the role(s) of Csp1, we compared phenotypic differences and transcriptome profiles between the wild type and a csp1 deletion mutant (Δcsp1). Csp1 contributes to attachment and long-term survival and influences gene expression. We observed reduced cell-to-cell attachment and reduced attachment to surfaces with the Δcsp1 strain compared to those with the wild type. Transmission electron microscopy imaging revealed that Δcsp1 was deficient in pili formation compared to the wild type and complemented strains. The Δcsp1 strain also showed reduced survival after long-term growth in vitro. Long-read nanopore transcriptome sequencing (RNA-Seq) analysis revealed changes in expression of several genes important for attachment and biofilm formation in Δcsp1 compared to that in the wild type. One gene of interest, pilA1, which encodes a type IV pili subunit protein, was upregulated in Δcsp1. Deleting pilA1 in X. fastidiosa strain Stag’s Leap increased surface attachment in vitro and reduced virulence in grapevines. X. fastidiosa virulence depends on bacterial attachment to host tissue and movement within and between xylem vessels. Our results show that the impact of Csp1 on virulence may be due to changes in expression of attachment genes. IMPORTANCE Xylella fastidiosa is a major threat to the worldwide agriculture industry. Despite its global importance, many aspects of X. fastidiosa biology and pathogenicity are poorly understood. There are currently few effective solutions to suppress X. fastidiosa disease development or eliminate bacteria from infected plants. Recently, disease epidemics due to X. fastidiosa have greatly expanded, increasing the need for better disease prevention and control strategies. Our studies show a novel connection between cold shock protein Csp1 and pili abundance and attachment, which have not been reported for X. fastidiosa. Understanding how pathogenesis-related gene expression is regulated can aid in developing novel pathogen and disease control strategies. We also streamlined a bioinformatics protocol to process and analyze long-read nanopore bacterial RNA-Seq data, which will benefit the research community, particularly those working with non-model bacterial species.https://journals.asm.org/doi/10.1128/Spectrum.01591-21RNA-seqXylella fastidiosabiofilmscold shock proteinsgene expressionplant pathogens
spellingShingle Wei Wei
Teresa Sawyer
Lindsey Burbank
Csp1, a Cold Shock Protein Homolog in Xylella fastidiosa Influences Cell Attachment, Pili Formation, and Gene Expression
Microbiology Spectrum
RNA-seq
Xylella fastidiosa
biofilms
cold shock proteins
gene expression
plant pathogens
title Csp1, a Cold Shock Protein Homolog in Xylella fastidiosa Influences Cell Attachment, Pili Formation, and Gene Expression
title_full Csp1, a Cold Shock Protein Homolog in Xylella fastidiosa Influences Cell Attachment, Pili Formation, and Gene Expression
title_fullStr Csp1, a Cold Shock Protein Homolog in Xylella fastidiosa Influences Cell Attachment, Pili Formation, and Gene Expression
title_full_unstemmed Csp1, a Cold Shock Protein Homolog in Xylella fastidiosa Influences Cell Attachment, Pili Formation, and Gene Expression
title_short Csp1, a Cold Shock Protein Homolog in Xylella fastidiosa Influences Cell Attachment, Pili Formation, and Gene Expression
title_sort csp1 a cold shock protein homolog in xylella fastidiosa influences cell attachment pili formation and gene expression
topic RNA-seq
Xylella fastidiosa
biofilms
cold shock proteins
gene expression
plant pathogens
url https://journals.asm.org/doi/10.1128/Spectrum.01591-21
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