Related Experiment Video
Updated: Jul 17, 2026
11:16
A Hydroponic Co-cultivation System for Simultaneous and Systematic Analysis of Plant/Microbe Molecular Interactions and Signaling
Published on: July 22, 2017
Functional interplay between two Xanthomonas oryzae pv,. oryzae secretion systems in modulating virulence on rice
Gopaljee Jha1, Ramanan Rajeshwari, Ramesh V Sonti
1Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad-500 007, A.P., India.
Molecular Plant-Microbe Interactions : MPMI
|January 26, 2007
Summary
Xanthomonas oryzae pv. oryzae uses type II secretion system (T2S) to deliver virulence factors that trigger rice defenses. Type III secretion system (T3S) effectors suppress these defenses, enabling bacterial leaf blight infection.
Area of Science:
- Plant Pathology
- Microbial Pathogenesis
- Molecular Biology
Background:
- Type II (T2S) and type III (T3S) secretion systems are crucial for Xanthomonas oryzae pv. oryzae virulence in rice.
- T3S suppresses host defenses, while T2S secretes cell-wall-degrading enzymes.
Purpose of the Study:
- Investigate the roles of T2S and T3S in X. oryzae pv. oryzae virulence and host interaction.
- Identify and characterize T2S effectors and their impact on rice defense.
Main Methods:
- Generated T3S-deficient and T2S-T3S double mutants of X. oryzae pv. oryzae.
- Purified and characterized T2S effectors: cellulase (ClsA), cellobiosidase (CbsA), and lipase/esterase (LipA).
- Assessed induction of rice defense responses (callose deposition, cell death) and virulence of mutant strains.
Main Results:
- T3S-deficient mutants induced basal rice defenses and conferred immunity.
- T2S effectors ClsA, CbsA, and LipA induced defense responses suppressed by T3S.
- Mutants lacking key T2S effectors (CbsA- or ClsA- LipA-) showed severe virulence deficiency.
Conclusions:
- X. oryzae pv. oryzae T2S secretes virulence factors that elicit rice innate immunity.
- T3S effectors counteract these defenses, facilitating pathogen infection.
- T2S effectors are essential for virulence, highlighting a complex interplay between secretion systems and host defense.
Related Concept Videos
01:28Regulation of Bacterial Virulence
Pathogenic bacteria employ a range of regulatory mechanisms to modulate the expression of virulence genes in response to environmental and host-derived signals. These mechanisms ensure that virulence factors are expressed only under favorable conditions, thereby optimizing infection and survival strategies.Mechanisms of Virulence RegulationKey regulatory strategies include:Two-Component Systems: These consist of a membrane-bound sensor kinase and a cytoplasmic response regulator. Environmental...
01:09Microbe-Plant Interactions
Microbe-plant interactions represent a dynamic spectrum of associations shaped by intricate chemical signaling. These interactions can be neutral, beneficial, or detrimental, and profoundly influence plant physiology, growth, and ecosystem function. The plant microbiome, comprising bacteria, fungi, archaea, protists, and viruses, plays a pivotal role in mediating these effects through surface colonization, internal colonization, or systemic symbiosis.Mutualistic associations, particularly with...
01:28Gene Regulation in Microbial Communities: Quorum Sensing
Quorum sensing is a mechanism of bacterial communication that enables coordinated gene expression in response to changes in population density. This facilitates collective behaviors that enhance survival, resource acquisition, and ecological adaptation. This process relies on small signaling molecules called autoinducers that accumulate as bacterial populations grow. When a critical threshold concentration of autoinducers is reached, bacterial cells collectively modify gene expression,...
01:20Determinants of Bacterial Pathogenicity and Virulence
Pathogenic bacteria employ a variety of strategies to establish infections, including the secretion of extracellular enzymes that act as potent virulence factors. These enzymes facilitate bacterial colonization of host tissues and help evade immune surveillance. By targeting structural components of host tissues and interfering with immune mechanisms, these enzymes play a pivotal role in disease progression.Extracellular Enzymes Facilitating Tissue Invasion: Several bacterial pathogens secrete...
01:26Microbial Interactions: Cooperation
Microbial cooperation involves beneficial interactions in which different species work together for individual or mutual advantage. These interactions can profoundly influence ecological dynamics and evolutionary processes, and they are essential to many pathogenic and symbiotic relationships.Nematode–Bacteria CooperationA striking example is the relationship between the Gram-negative bacterium Xenorhabdus nematophila and the parasitic nematode Steinernema carpocapsae. Juvenile nematodes...
01:28Global Regulatory Systems
Global regulatory systems in bacteria enable rapid and coordinated responses to environmental changes by integrating sensory inputs with gene expression, ensuring efficient adaptation to fluctuating conditions. Key global regulatory mechanisms include regulons, two-component systems, sigma factors, and secondary messengers.Regulons and Global RegulatorsA regulon is a collection of genes and operons controlled by a common global regulator. These regulators enable bacteria to prioritize resource...