Recognition of Avirulence Gene AvrLm1 from Hemibiotrophic Ascomycete Leptosphaeria maculans Triggers Salicylic Acid and Ethylene Signaling in Brassica napus

Interaction of a plant with a fungal pathogen is an encounter with hundreds of molecules. In contrast to this, a single molecule often decides between the disease and resistance. In the present article, we describe the defense responses triggered by AvrLm1, an avirulence gene from a hemibiotrophic ascomycete, Leptosphaeria maculans, responsible for an incompatible interaction with Brassica napus. Using multiple hormone quantification and expression analysis of defense-related genes, we investigated signaling events in Rlm1 plants infected with two sister isolates of L. maculans differentiated by the presence or absence of AvrLm1. Infection with the isolate carrying AvrLm1 increased the biosynthesis of salicylic acid (SA) and induced expression of the SA-associated genes ICS1, WRKY70, and PR-1, a feature characteristic of responses to biotrophic pathogens and resistance gene-mediated resistance. In addition to SA-signaling elements, we also observed the induction of ASC2a, HEL, and CHI genes associated with ethylene (ET) signaling. Pharmacological experiments confirmed the positive roles of SA and ET in mediating resistance to L. maculans. The unusual cooperation of SA and ET signaling might be a response to the hemibiotrophic nature of L. maculans. Our results also demonstrate the profound difference between the natural host B. napus and the model plant Arabidopsis in their response to L. maculans infection

Mesoporous carbon-containing voltammetric biosensor for determination of tyramine in food products

A voltammetric biosensor based on tyrosinase (TYR) was developed for determination of tyramine. Carbon material (multi-walled carbon nanotubes or mesoporous carbon CMK-3-type), polycationic polymer—i.e., poly(diallyldimethylammonium chloride) (PDDA), and Nafion were incorporated into titania dioxide sol (TiO(2)) to create an immobilization matrix. The features of the formed matrix were studied by scanning electron microscopy (SEM) and cyclic voltammetry (CV). The analytical performance of the developed biosensor was evaluated with respect to linear range, sensitivity, limit of detection, long-term stability, repeatability, and reproducibility. The biosensor exhibited electrocatalytic activity toward tyramine oxidation within a linear range from 6 to 130 μM, high sensitivity of 486 μA mM(−1) cm(−2), and limit of detection of 1.5 μM. The apparent Michaelis–Menten constant was calculated to be 66.0 μM indicating a high biological affinity of the developed biosensor for tyramine. Furthermore, its usefulness in determination of tyramine in food product samples was also verified. [Figure: see text] ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00216-016-9612-y) contains supplementary material, which is available to authorized users

Purification and Characterization of a Novel Hypersensitive Response-Inducing Elicitor from Magnaporthe oryzae that Triggers Defense Response in Rice

<div><h3>Background</h3><p><em>Magnaporthe oryzae</em>, the rice blast fungus, might secrete certain proteins related to plant-fungal pathogen interactions.</p> <h3>Methodology/Principal Findings</h3><p>In this study, we report the purification, characterization, and gene cloning of a novel hypersensitive response-inducing protein elicitor (MoHrip1) secreted by <em>M. oryzae</em>. The protein fraction was purified and identified by de novo sequencing, and the sequence matched the genomic sequence of a putative protein from <em>M. oryzae</em> strain 70-15 (GenBank accession No. XP_366602.1). The elicitor-encoding gene <em>mohrip1</em> was isolated; it consisted of a 429 bp cDNA, which encodes a polypeptide of 142 amino acids with a molecular weight of 14.322 kDa and a pI of 4.53. The deduced protein, MoHrip1, was expressed in <em>E. coli</em>. And the expression protein collected from bacterium also forms necrotic lesions in tobacco. MoHrip1 could induce the early events of the defense response, including hydrogen peroxide production, callose deposition, and alkalization of the extracellular medium, in tobacco. Moreover, MoHrip1-treated rice seedlings possessed significantly enhanced systemic resistance to <em>M. oryzae</em> compared to the control seedlings. The real-time PCR results indicated that the expression of some pathogenesis-related genes and genes involved in signal transduction could also be induced by MoHrip1.</p> <h3>Conclusion/Significance</h3><p>The results demonstrate that MoHrip1 triggers defense responses in rice and could be used for controlling rice blast disease.</p> </div

Antiquaquibacter oligotrophicus gen. nov., sp. nov., a novel oligotrophic bacterium from groundwater.

In this study, a Gram-stain-positive, non-motile, oxidase- and catalase-negative, rod-shaped, bacterial strain (SG_E_30_P1T) that formed light yellow colonies was isolated from a groundwater sample of Sztaravoda spring, Hungary. Based on 16S rRNA phylogenetic and phylogenomic analyses, the strain was found to form a distinct linage within the family Microbacteriaceae. Its closest relatives in terms of near full-length 16S rRNA gene sequences are Salinibacterium hongtaonis MH299814 (97.72 % sequence similarity) and Leifsonia psychrotolerans GQ406810 (97.57 %). The novel strain grows optimally at 20-28 °C, at neutral pH and in the presence of NaCl (1-2 w/v%). Strain SG_E_30_P1T contains MK-7 and B-type peptidoglycan with diaminobutyrate as the diagnostic amino acid. The major cellular fatty acids are anteiso-C15 : 0, iso-C16 : 0 and iso-C14 : 0, and the polar lipid profile is composed of diphosphatidylglycerol and phosphatidylglycerol, as well as an unidentified aminoglycolipid, aminophospholipid and some unidentified phospholipids. The assembled draft genome is a contig with a total length of 2 897 968 bp and a DNA G+C content of 65.5 mol%. Amino acid identity values with it closest relatives with sequenced genomes of &lt;62.54 %, as well as other genome distance results, indicate that this bacterium represents a novel genus within the family Microbacteriaceae. We suggest that SG_E_30_P1T (=DSM 111415T=NCAIM B.02656T) represents the type strain of a novel genus and species for which the name Antiquaquibacter oligotrophicus gen. nov., sp. nov. is proposed

Author Correction: Genome expansion and lineage-specific genetic innovations in the forest pathogenic fungi Armillaria.

The Publisher In the version of this Article originally published, it was incorrectly stated that &ldquo;16,687 protein-coding genes were inferred for the most recent common ancestor (MRCA) of Armillaria&rdquo;; the value was incorrect and it should have read &ldquo;15,787&rdquo;. This has now been corrected