Modulates Salt Stress and ABA Responses in .

Salt is one of the most common abiotic stresses, causing ionic and osmotic pressure changes that affect plant growth and development. In this work, we present molecular and genetic evidence that is involved in both salt stress and in the abscisic acid response to this stress. We demonstrate that is highly induced in response to salt stress and that mutants have a lower germination rate, decreased root length, and lower survival rate compared to the wild-type in response to salt stress.

The E3 Ubiquitin Ligase ATL9 Affects Expression of Defense Related Genes, Cell Death and Callose Deposition in Response to Fungal Infection.

Plants use diverse strategies to defend themselves from biotic stresses in nature, which include the activation of defense gene expression and a variety of signal transduction pathways. Previous studies have shown that protein ubiquitination plays a critical role in plant defense responses, however the details of its function remain unclear. Our previous work has shown that increasing expression levels of , an E3 ubiquitin ligase in increased resistance to infection by the fungal pathogen, .

(): A Gene Involved in Chitin-Induced, Hormone-Related and NADPH Oxidase-Mediated Defense Responses.

Plants, as sessile organisms, have evolved complex systems to respond to changes in environmental conditions. Chitin is a Pathogen-Associated-Molecular Pattern (PAMP) that exists in the fungal cell walls, and can be recognized by plants and induce plant pattern-triggered immunity (PTI). Our previous studies showed that is highly induced in response to fungal infection and chitin treatment.

Expression and regulation of ATL9, an E3 ubiquitin ligase involved in plant defense.

Plants are continually exposed to a variety of pathogenic organisms, including bacteria, fungi and viruses. In response to these assaults, plants have developed various defense pathways to protect themselves from pathogen invasion. An understanding of the expression and regulation of genes involved in defense signaling is essential to controlling plant disease.

Short-Chain Chitin Oligomers: Promoters of Plant Growth.

Chitin is the second most abundant biopolymer in nature after cellulose, and it forms an integral part of insect exoskeletons, crustacean shells, krill and the cell walls of fungal spores, where it is present as a high-molecular-weight molecule. In this study, we showed that a chitin oligosaccharide of lower molecular weight (tetramer) induced genes in that are principally related to vegetative growth, development and carbon and nitrogen metabolism. Based on plant responses to this chitin tetramer, a low-molecular-weight chitin mix (CHL) enriched to 92% with dimers (2mer), trimers (3mer) and tetramers (4mer) was produced for potential use in biotechnological processes.

Developmental and Reproductive Effects of Iron Oxide Nanoparticles in Arabidopsis thaliana.

Increasing use of iron oxide nanoparticles in medicine and environmental remediation has led to concerns regarding exposure of these nanoparticles to the public. However, limited studies are available to evaluate their effects on the environment, in particular on plants and food crops. Here, we investigated the effects of positive (PC) and negative (NC) charged iron oxide (Fe₂O₃) nanoparticles (IONPs) on the physiology and reproductive capacity of Arabidopsis thaliana at concentrations of 3 and 25 mg/L.

ATL9, a RING zinc finger protein with E3 ubiquitin ligase activity implicated in chitin- and NADPH oxidase-mediated defense responses.

Pathogen associated molecular patterns (PAMPs) are signals detected by plants that activate basal defenses. One of these PAMPs is chitin, a carbohydrate present in the cell walls of fungi and in insect exoskeletons. Previous work has shown that chitin treatment of Arabidopsis thaliana induced defense-related genes in the absence of a pathogen and that the response was independent of the salicylic acid (SA), jasmonic acid (JA) and ethylene (ET) signaling pathways.

A LysM receptor-like kinase plays a critical role in chitin signaling and fungal resistance in Arabidopsis.

Chitin, a polymer of N-acetyl-d-glucosamine, is found in fungal cell walls but not in plants. Plant cells can perceive chitin fragments (chitooligosaccharides) leading to gene induction and defense responses. We identified a LysM receptor-like protein (LysM RLK1) required for chitin signaling in Arabidopsis thaliana.

The role and regulation of receptor-like kinases in plant defense.

Receptor-like kinases (RLKs) in plants are a large superfamily of proteins that are structurally similar. RLKs are involved in a diverse array of plant responses including development, growth, hormone perception and the response to pathogens. Current studies have focused attention on plant receptor-like kinases as an important class of sentinels acting in plant defense responses.

Loss-of-function mutations in chitin responsive genes show increased susceptibility to the powdery mildew pathogen Erysiphe cichoracearum.

Chitin is a major component of fungal walls and insect exoskeletons. Plants produce chitinases upon pathogen attack and chito-oligomers induce defense responses in plants, though the exact mechanism behind this response is unknown. Using the ATH1 Affymetrix microarrays consisting of about 23,000 genes, we examined the response of Arabidopsis (Arabidopsis thaliana) seedlings to chito-octamers and hydrolyzed chitin after 30 min of treatment.

The PEN1 syntaxin defines a novel cellular compartment upon fungal attack and is required for the timely assembly of papillae.

Attack by the host powdery mildew Erysiphe cichoracearum usually results in successful penetration and rapid proliferation of the fungus on Arabidopsis. By contrast, the nonhost barley powdery mildew Blumeria graminis f. sp.

Characterization of early, chitin-induced gene expression in Arabidopsis.

Three genes (i.e., a zinc finger protein, a lectin-like protein, and AtMPK3), previously shown to respond to chitin elicitation in microarray experiments, were used to examine the response of Arabidopsis spp.

Microarray analysis of chitin elicitation in Arabidopsis thaliana.

Summary Chitin oligomers, released from fungal cell walls by endochitinase, induce defence and related cellular responses in many plants. However, little is known about chitin responses in the model plant Arabidopsis. We describe here a large-scale characterization of gene expression patterns in Arabidopsis in response to chitin treatment using an Arabidopsis microarray consisting of 2375 EST clones representing putative defence-related and regulatory genes.

The genomics parade of defense responses: to infinity and beyond.

Genomic-scale methods, such as cDNA microarrays, cDNA-AFLP analyses and proteomics are revolutionizing the study of plant-pathogen interactions, and are revealing a complex web of signaling cascades involved in plant defense responses. Recent studies have shown that responses to pathogens and environmental stresses are linked, suggesting that genes previously identified as stress-responsive may also play an active role in plant defense. As a result of proteomic analysis, proteins involved in early defense signaling are coming to light.