Article

Molecular crosstalk between PAMP-triggered immunity and photosynthesis.

Heinrich-Heine University, Dusseldorf, Germany.
Molecular Plant-Microbe Interactions (Impact Factor: 4.31). 05/2012; 25(8):1083-92. DOI: 10.1094/MPMI-11-11-0301
Source: PubMed

ABSTRACT The innate immune system allows plants to respond to potential pathogens in an appropriate manner while minimizing damage and energy costs. Photosynthesis provides a sustained energy supply and, therefore, has to be integrated into the defense against pathogens. Although changes in photosynthetic activity during infection have been described, a detailed and conclusive characterization is lacking. Here, we addressed whether activation of early defense responses by pathogen-associated molecular patterns (PAMPs) triggers changes in photosynthesis. Using proteomics and chlorophyll fluorescence measurements, we show that activation of defense by PAMPs leads to a rapid decrease in nonphotochemical quenching (NPQ). Conversely, NPQ also influences several responses of PAMP-triggered immunity. In a mutant impaired in NPQ, apoplastic reactive oxygen species production is enhanced and defense gene expression is differentially affected. Although induction of the early defense markers WRKY22 and WRKY29 is enhanced, induction of the late markers PR1 and PR5 is completely abolished. We propose that regulation of NPQ is an intrinsic component of the plant's defense program.

0 Bookmarks
 · 
356 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Many defense mechanisms contribute to the plant immune system against pathogen, involving the regulation of different processes of the primary and secondary metabolism. At the same time, pathogens have evolved mechanisms to hijack the plant defense in order to establish the infection and proliferate. Localization and timing of the host response is essential to understand defense mechanisms and resistance to pathogens (Rico et al. 2011). Imaging technics, such as fluorescence imaging and thermography, are a very valuable tool providing spatial and temporal information about a series of plant processes. In this study, bean plants challenged with two pathovars of Pseudomonas syringae have been investigated. P. syringae pv. phaseolicola 1448A and P. syringae pv. tomato DC3000 elicit a compatible and incompatible interaction in bean, respectively. Both types of host-pathogen interaction triggered different changes in the activity of photosynthesis and the secondary metabolism. We conclude that the combined analysis of leaf temperature, chlorophyll fluorescence and green fluorescence emitted by phenolics allows to discriminate compatible from incompatible P. syringae - P. vulgaris interactions in very early times of the infection, prior to the development of symptoms. These can constitute disease signatures that would allow an early identification of emerging plagues in crops.
    Physiologia Plantarum 05/2014; · 3.66 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Growth-defense tradeoffs are thought to occur in plants due to resource restrictions, which demand prioritization towards either growth or defense depending on external and internal factors. These tradeoffs have profound implications in agriculture and natural ecosystems, as both processes are vital for plant survival and reproduction and, ultimately, plant fitness. While many of the molecular mechanisms underlying growth and defense tradeoffs remain to be elucidated, hormone crosstalk has emerged as a major player in regulating tradeoffs needed to achieve a balance. In this review, we cover recent advances in understanding growth-defense tradeoffs in plants as well as what is known regarding the underlying molecular mechanisms. Specifically, we address evidence supporting the growth-defense tradeoff concept, as well as known interactions between defense signaling and growth signaling. Understanding the molecular basis of these tradeoffs in plants should provide a foundation for the development of breeding strategies that optimize the growth-defense balance to maximize crop yield to meet rising global food and biofuel demands.
    Molecular Plant 04/2014; 7:1267-1287. · 6.13 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: To study the molecular mechanism that underpins crosstalk between plant growth and disease resistance, we performed a mutant screening on tobacco and created a recessive mutation that caused the phenotype of growth enhancement and resistance impairment (geri1). In the geri1 mutant, growth enhancement accompanies promoted expression of growth-promoting genes, whereas repressed expression of defense response genes is consistent with impaired resistance to diseases caused by viral, bacterial, and oomycete pathogens. The geri1 allele identifies a single genetic locus hypothetically containing the tagged GERI1 gene. The isolated GERI1 gene was predicted to encode auxin-repressed protein ARP1, which was determined to be 13.5 kDa in size. The ARP1/GERI1 gene was further characterized as a repressor of plant growth and an activator of disease resistance based on genetic complementation, gene silencing, and overexpression analyses. ARP1/GERI1 resembles pathogen-associated molecular patterns and is required for them to repress plant growth and activate plant immunity responses. ARP1/GERI1 represses growth by inhibiting the expression of AUXIN RESPONSE FACTOR gene ARF8, and ARP1/GERI1 recruits the NPR1 gene, which is essential for the salicylic-acid-mediated defense, to coregulate disease resistance. In conclusion, ARP1/GERI1 is an integral regulator for crosstalk between growth and disease resistance in the plant.
    Molecular Plant-Microbe Interactions 07/2014; 27(7):638-54. · 4.31 Impact Factor

Full-text

View
177 Downloads
Available from
May 16, 2014