Competitive Index: Mixed Infection-Based Virulence Assays for Genetic Analysis in Pseudomonas syringae-Plant Interactions

2016 ◽  
pp. 209-217 ◽  
Author(s):  
Alberto P. Macho ◽  
José S. Rufián ◽  
Javier Ruiz-Albert ◽  
Carmen R. Beuzón
Keyword(s):  
Genetic Analysis ◽  
Pseudomonas Syringae ◽  
Mixed Infection ◽  
Plant Interactions ◽  
Competitive Index

Competitive index in mixed infections: a sensitive and accurate assay for the genetic analysis of Pseudomonas syringae?plant interactions

2007 ◽  
Vol 8 (4) ◽  
pp. 437-450 ◽  
Author(s):  
ALBERTO P. MACHO ◽  
ADELA ZUMAQUERO ◽  
INMACULADA ORTIZ-MARTÍN ◽  
CARMEN R. BEUZÓN
Keyword(s):  
Genetic Analysis ◽  
Pseudomonas Syringae ◽  
Mixed Infections ◽  
Plant Interactions ◽  
Competitive Index

Whitefly-mediated transmission and subsequent acquisition of highly similar and naturally occurring Tomato yellow leaf curl virus variants

2021 ◽  
Author(s):  
Wendy Marchant ◽  
Saurabh Gautam ◽  
Bhabesh Dutta ◽  
Rajagopalbab Srinivasan
Keyword(s):  
Amino Acids ◽  
Mixed Infection ◽  
Tomato Yellow Leaf ◽  
Yellow Leaf ◽  
Plant Interactions ◽  
Tomato Plants ◽  
Individual Host ◽  
Field Samples ◽  
Leaf Curl Virus ◽  
Leaf Curl

Begomoviruses are whitefly-transmitted viruses that infect many agricultural crops. Numerous reports exist on individual host plants harboring two or more begomoviruses. Mixed infection allows recombination events to occur among begomoviruses. However, very few studies have examined mixed infection of different isolates/variants/strains of a Begomovirus species in hosts. In this study, the frequency of mixed infection of tomato yellow leaf curl virus (TYLCV) variants in field-grown tomato was evaluated. At least 60% of symptomatic field samples were infected with more than one TYLCV variant. These variants differed by a few nucleotides and amino acids resembling a quasispecies. Subsequently, in the greenhouse, single and mixed infection of two TYLCV variants (“variant #2” and “variant #4”) that shared 99.5% nucleotide identity and differed by a few amino acids was examined. Plant-virus variant-whitefly interactions including transmission of one and/or two variants, variants’ concentrations, competition between variants in inoculated tomato plants, and whitefly acquisition of one and/or two variants were assessed. Whiteflies transmitted both variants to tomato plants at similar frequencies; however, the accumulation of variant #4 was greater than variant#2 in tomato plants. Despite differences in variants’ accumulation in inoculated tomato plants, whiteflies acquired variant #2 and variant #4 at similar frequencies. Also, whiteflies acquired greater amounts of TYLCV from singly-infected plants than from mixed-infected plants. These results demonstrated that even highly similar TYLCV variants could differentially influence component (whitefly-variant-plant) interactions.

Need for flagella for complete virulence of Pseudomonas syringae pv. tabaci: genetic analysis with flagella-defective mutants ?fliC and ?fliD in host tobacco plants

2003 ◽  
Vol 69 (4) ◽  
pp. 244-249 ◽  
Author(s):  
Yuki Ichinose ◽  
Rena Shimizu ◽  
Yoko Ikeda ◽  
Fumiko Taguchi ◽  
Mizuri Marutani ◽  
...  
Keyword(s):  
Genetic Analysis ◽  
Pseudomonas Syringae ◽  
Tobacco Plants

scholarly journals Genetic Analysis of Fluorescent Pigment Production in Pseudomonas syringae pv. syringae

Microbiology ◽  
1984 ◽  
Vol 130 (6) ◽  
pp. 1507-1515 ◽  
Author(s):  
J. E. Loper ◽  
C. S. Orser ◽  
N. J. Panopoulos ◽  
M. N. Schroth
Keyword(s):  
Genetic Analysis ◽  
Pseudomonas Syringae ◽  
Pigment Production ◽  
Fluorescent Pigment

scholarly journals PsrA, the Pseudomonas Sigma Regulator, Controls Regulators of Epiphytic Fitness, Quorum-Sensing Signals, and Plant Interactions in Pseudomonas syringae pv. tomato Strain DC3000

2007 ◽  
Vol 73 (11) ◽  
pp. 3684-3694 ◽  
Author(s):  
Asita Chatterjee ◽  
Yaya Cui ◽  
Hiroaki Hasegawa ◽  
Arun K. Chatterjee
Keyword(s):  
Quorum Sensing ◽  
Pseudomonas Syringae ◽  
Stress Responses ◽  
Sigma Factor ◽  
Rna Binding ◽  
Negative Regulator ◽  
Insertion Mutant ◽  
Plant Interactions ◽  
Mobility Shift ◽  
Quorum Sensing Signals

ABSTRACT Pseudomonas syringae pv. tomato strain DC3000, a pathogen of tomato and Arabidopsis, occurs as an epiphyte. It produces N-acyl homoserine lactones (AHLs) which apparently function as quorum-sensing signals. A Tn5 insertion mutant of DC3000, designated PsrA− (Psr is for Pseudomonas sigma regulator), overexpresses psyR (a LuxR-type regulator of psyI) and psyI (the gene for AHL synthase), and it produces a ca. 8-fold-higher level of AHL than does DC3000. The mutant is impaired in its ability to elicit the hypersensitive reaction and is attenuated in its virulence in tomato. These phenotypes correlate with reduced expression of hrpL, the gene for an alternate sigma factor, as well as several hrp and hop genes during early stages of incubation in a Hrp-inducing medium. PsrA also positively controls rpoS, the gene for an alternate sigma factor known to control various stress responses. By contrast, PsrA negatively regulates rsmA1, an RNA-binding protein gene known to function as negative regulator, and aefR, a tetR-like gene known to control AHL production and epiphytic fitness in P. syringae pv. syringae. Gel mobility shift assays and other lines of evidence demonstrate a direct interaction of PsrA protein with rpoS promoter DNA and aefR operator DNA. In addition, PsrA negatively autoregulates and binds the psrA operator. In an AefR− mutant, the expression of psyR and psyI and AHL production are lower than those in DC3000, the AefR+ parent. In an RpoS− mutant, on the other hand, the levels of AHL and transcripts of psyR and psyI are much higher than those in the RpoS+ parent, DC3000. We present evidence, albeit indirect, that the RpoS effect occurs via psyR. Thus, AefR positively regulates AHL production, whereas RpoS has a strong negative effect. We show that AefR and RpoS do not regulate PsrA and that the PsrA effect on AHL production is exerted via its cumulative, but independent, effects on both AefR and RpoS.

scholarly journals The ecological genetics ofPseudomonas syringaefrom kiwifruit leaves

2017 ◽  
Author(s):  
Christina Straub ◽  
Elena Colombi ◽  
Li Li ◽  
Hongwen Huang ◽  
Matthew D. Templeton ◽  
...  
Keyword(s):  
Population Structure ◽  
Pseudomonas Syringae ◽  
Bacterial Pathogen ◽  
Ecological Factors ◽  
Ecological Genetics ◽  
Plant Interactions ◽  
In Planta ◽  
Canker Disease ◽  
Pathogen Populations

SUMMARYInteractions between commensal microbes and invading pathogens are understudied, despite their likely effects on pathogen population structure and infection processes. We describe the population structure and genetic diversity of a broad range of co-occurringPseudomonas syringaeisolated from infected and uninfected kiwifruit during an outbreak of bleeding canker disease caused byP. syringaepv.actinidiae(Psa) in New Zealand. Overall population structure was clonal and affected by ecological factors including infection status and cultivar. Most isolates are members of a new clade in phylogroup 3 (PG3a), also present on kiwifruit leaves in China and Japan. Stability of the polymorphism between pathogenicPsaand commensalP. syringaePG3a isolated from the same leaf was tested using reciprocal invasion from rare assaysin vitroand in planta.P. syringaeG33C (PG3a) inhibitedPsaNZ54, while the presence ofPsaNZ54 enhanced the growth ofP. syringaeG33C. This effect could not be attributed to virulence activity encoded by the Type 3 secretion system ofPsa. Together our data contribute toward the development of an ecological perspective on the genetic structure of pathogen populations.ORIGINALITY-SIGNIFICANT STATEMENTBacterial pathogen populations are often studied with little consideration of co-occurring microbes and yet interactions between pathogens and commensals can affect both population structure and disease progression. A fine-scale sampling of commensals present on kiwifruit leaves during an outbreak of bleeding canker disease caused byP. syringaepv.actinidiaereveals a clonal population structure. A new clade of non-pathogenicP. syringae(PG3a) appears to be associated with kiwifruit on a global scale. The presence of PG3a on kiwifruit has significant effects on the outcome of infection byP. syringaepv.actinidiae. This emphasises the value of studying the effect of co-occurring bacteria on pathogen-plant interactions.

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