Engineering with a Type III Secretion System to Express Type III Effectors.

Plants elicit defense responses when exposed to pathogens, which partly contribute to the resistance of plants to Agrobacterium tumefaciens-mediated transformation. Some pathogenic bacteria have sophisticated mechanisms to counteract these defense responses by injecting Type III effectors (T3Es) through the Type III secretion system (T3SS). By engineering to express T3SS to deliver T3Es, we suppressed plant defense and enhanced plant genetic transformation.

Agrobacterium expressing a type III secretion system delivers Pseudomonas effectors into plant cells to enhance transformation.

Agrobacterium-mediated plant transformation (AMT) is the basis of modern-day plant biotechnology. One major drawback of this technology is the recalcitrance of many plant species/varieties to Agrobacterium infection, most likely caused by elicitation of plant defense responses. Here, we develop a strategy to increase AMT by engineering Agrobacterium tumefaciens to express a type III secretion system (T3SS) from Pseudomonas syringae and individually deliver the P.

Overexpression of VIRE2-INTERACTING PROTEIN2 in Arabidopsis regulates genes involved in Agrobacterium-mediated plant transformation and abiotic stresses.

Arabidopsis VIRE2-INTERACTING PROTEIN2 (VIP2) was previously described as a protein with a NOT domain, and Arabidopsis vip2 mutants are recalcitrant to Agrobacterium-mediated root transformation. Here we show that VIP2 is a transcription regulator and the C-terminal NOT2 domain of VIP2 interacts with VirE2. Interestingly, AtVIP2 overexpressor lines in Arabidopsis did not show an improvement in Agrobacterium-mediated stable root transformation, but the transcriptome analysis identified 1,634 differentially expressed genes compared to wild-type.

Physiological Studies of Suggest that Bacillithiol Derivatives Are the Most Widespread Thiols in Bacteria.

Low-molecular-weight (LMW) thiols mediate redox homeostasis and the detoxification of chemical stressors. Despite their essential functions, the distribution of LMW thiols across cellular life has not yet been defined. LMW thiols are also thought to play a central role in sulfur oxidation pathways in phototrophic bacteria, including the Here we show that synthesizes a novel LMW thiol with a mass of 412 ± 1 Da corresponding to a molecular formula of CHNOS, which suggests that the new LMW thiol is closely related to bacillithiol (BSH), the major LMW thiol of low-G+C Gram-positive bacteria.

Differential RNA Sequencing Implicates Sulfide as the Master Regulator of S Metabolism in Chlorobaculum tepidum and Other Green Sulfur Bacteria.

The green sulfur bacteria () are anaerobes that use electrons from reduced sulfur compounds (sulfide, S, and thiosulfate) as electron donors for photoautotrophic growth. , the model system for the , both produces and consumes extracellular S globules depending on the availability of sulfide in the environment. These physiological changes imply significant changes in gene regulation, which has been observed when sulfide is added to growing on thiosulfate.

Small RNA Functions Are Required for Growth and Development of Magnaporthe oryzae.

RNA interference (RNAi) is conserved in eukaryotic organisms, and it has been well studied in many animal and plant species and some fungal species, yet it is not well studied in fungal plant pathogens. In the rice blast fungus Magnaporthe oryzae, we examined small RNA (sRNA) and their biogenesis in the context of growth and pathogenicity. Through genetic and genomic analyses, we demonstrate that loss of a single gene encoding Dicer, RNA-dependent RNA polymerase, or Argonaute reduces sRNA levels.

Global gene expression in rice blast pathogen Magnaporthe oryzae treated with a natural rice soil isolate.

The rhizospheric microbiome is comprised of many microbes, some of which reduce the virulence of their phytopathogenic neighbors; however, the mechanisms underlying these interactions are largely unknown. Rice soil isolate Pseudomonas chlororaphis EA105 strongly inhibits Magnaporthe oryzae's in vitro growth by restricting fungal diameter as well as inhibiting the formation of the appressorium, required for penetration. We were interested in elucidating M.

Transcriptomics of the rice blast fungus Magnaporthe oryzae in response to the bacterial antagonist Lysobacter enzymogenes reveals candidate fungal defense response genes.

Plants and animals have evolved a first line of defense response to pathogens called innate or basal immunity. While basal defenses in these organisms are well studied, there is almost a complete lack of understanding of such systems in fungal species, and more specifically, how they are able to detect and mount a defense response upon pathogen attack. Hence, the goal of the present study was to understand how fungi respond to biotic stress by assessing the transcriptional profile of the rice blast pathogen, Magnaporthe oryzae, when challenged with the bacterial antagonist Lysobacter enzymogenes.

Physiological stressors and invasive plant infections alter the small RNA transcriptome of the rice blast fungus, Magnaporthe oryzae.

Background: The rice blast fungus, Magnaporthe oryzae is a destructive pathogen of rice and other related crops, causing significant yield losses worldwide. Endogenous small RNAs (sRNAs), including small interfering RNAs (siRNAs) and microRNAs (miRNAs) are critical components of gene regulation in many eukaryotic organisms. Recently several new species of sRNAs have been identified in fungi.

Roles and delivery mechanisms of fungal effectors during infection development: common threads and new directions.

Fungal effectors have often been referred as a 'sea of diversity', but recently, experiments have shed some light onto effector biology, including discovery that unrelated fungi utilize some common methods for creating a more compatible host environment. A wheat pathogen and a rice pathogen, for example, have evolved mechanisms to suppress chitin-mediated basal defenses in their respective plant hosts. Smut fungi, on the other hand, might have evolved a unique mechanism to manipulate their host environment by altering cell metabolism.

Regulation of carotenoid biosynthetic genes expression and carotenoid accumulation in the green alga Haematococcus pluvialis under nutrient stress conditions.

Haematococcus pluvialis, a green alga, accumulates carotenoids, predominantly astaxanthin, when exposed to stress conditions. In the present work, changes in the pigment profile and expression of carotenogenic genes under various nutrient stress conditions and their regulation were studied. Nutrient stress and higher light intensity in combination with NaCl/sodium acetate (SA) enhanced total carotenoid and total astaxanthin content to 32.

Differential expression of carotenogenic genes and associated changes in pigment profile during regeneration of Haematococcus pluvialis cysts.

Haematococcus pluvialis is a green alga known to accumulate astaxanthin in extra-plastidic lipid vesicles under stress conditions. The present study revealed the influence of few cultural parameters and temperature treatments on regeneration efficiency of red cysts along with changes in pigment profile and expression of carotenogenic genes during regeneration. Regeneration efficiency has been improved by incubating less aged cyst cells in a medium containing ammonium carbonate, 16:8 light-dark cycle with a light intensity of 30 mumol m(-2) s(-1).