To explore the role of plant mitochondria in regulation cellular redox homeostasis and stress resistance, we exploited a Nicotiana sylvestris mitochondrial mutant. The cytoplasmic male-sterile mutant (CMSII) is impaired complex I function displays enhanced nonphosphorylating rotenone-insensitive [NAD(P)H dehydrogenases] cyanide-insensitive (alternative oxidase) respiration. Loss not associated with increased oxidative stress, as shown by decreased leaf H2O2 maintenance glutathione ascorbate...

Abstract Background Mitogen-activated protein kinases (MAPKs) are key regulators of immune responses in animals and plants. In Arabidopsis , perception microbe-associated molecular patterns (MAMPs) activates the MAPKs MPK3, MPK4 MPK6. Increasing information depicts events activated by MAMPs plants, but specific cooperative contributions these signalling largely unclear. Results this work, we analyse behaviour MPK3 MPK6 mutants early late triggered MAMP flg22 from bacterial flagellin. A...

Alternative oxidase (AOX) functions in stress resistance by preventing accumulation of reactive oxygen species (ROS), but little is known about vivo partitioning electron flow between AOX and the cytochrome pathway. We investigated relationships expression activity Nicotiana sylvestris complex I–deficient CMSII mutant response to a cell death elicitor. While specific AOX1 isoform active reduced state was constitutively overexpressed CMSII, through alternative pathway similar wild type. Lack...

Abstract Mitochondrial complex I is a major avenue for reduced NAD oxidation linked to oxidative phosphorylation in plants. However, the plant enzyme has structural and functional features that set it apart from its counterparts other organisms, raising questions about physiological significance of this We have developed an experimental model which rotenone, classic inhibitor, been applied Arabidopsis (Arabidopsis thaliana) cell suspension cultures order dissect early metabolic adjustments...

Abstract Phosphite (Phi), a phloem-mobile oxyanion of phosphorous acid (H3PO3), protects plants against diseases caused by oomycetes. Its mode action is unclear, as evidence indicates both direct antibiotic effects on pathogens well inhibition through enhanced plant defense responses, and its target(s) in the unknown. Here, we demonstrate that biotrophic oomycete Hyaloperonospora arabidopsidis (Hpa) exhibits an unusual biphasic dose-dependent response to Phi after inoculation Arabidopsis...

Immunity and senescence play a crucial role in the functioning of legume symbiotic nodules. The miss-regulation one these processes compromises symbiosis leading to death endosymbiont arrest nodule functioning. relationship between immunity has been extensively studied plant organs where synergistic response can be observed. However, interplay organ is poorly discussed literature phenomena are often mixed up. Recent studies revealed that cooperation not always observed nodule, suggesting...

Secondary metabolism plant glycosyltransferases (UGTs) ensure conjugation of sugar moieties to secondary metabolites (SMs) and glycosylation contributes the great diversity, reactivity regulation SMs. UGT73B3 UGT73B5, two UGTs Arabidopsis thaliana (Arabidopsis), are involved in hypersensitive response (HR) avirulent bacteria Pseudomonas syringae pv. tomato (Pst-AvrRpm1), but their function planta is unknown. Here, we report that ugt73b3, ugt73b5 ugt73b3 T-DNA insertion mutants exhibited an...

Abstract Programmed cell death (PCD) is essential for several aspects of plant life, including development and stress responses. Indeed, incompatible plant-pathogen interactions are well known to induce the hypersensitive response, a localized death. Mutational analyses have identified key PCD components, we recently mips1 mutant Arabidopsis (Arabidopsis thaliana), which deficient enzyme catalyzing limiting step myoinositol synthesis. One most striking features light-dependent formation...

Mitogen-activated protein kinases (MAPKs) are important regulators of plant immunity. Most the knowledge about function these pathways is derived from loss-of-function approaches. Using a gain-of-function approach, we investigated responses controlled by constitutively active (CA) MPK3 in Arabidopsis thaliana. CA-MPK3 plants dwarfed and display massive derepression defense genes associated with spontaneous cell death as well accumulation reactive oxygen species, phytoalexins, stress-related...

Summary An Arabidopsis thaliana mutant, esa1 , that shows enhanced susceptibility to the necrotrophic pathogens Alternaria brassicicola Botrytis cinerea and Plectosphaerella cucumerina but has wild‐type levels of resistance biotrophic Pseudomonas syringae pv. tomato Peronospora parasitica . The towards correlated with a delayed induction phytoalexin accumulation plant defensin gene PDF1.2 upon inoculation pathogens. Two reactive oxygen generating compounds, paraquat acifluorfen, were found...

Secondary metabolites (SMs) play key roles in pathogen responses, although knowledge of their precise functions is limited by insufficient characterization spatial response. The present study addressed this issue Arabidopsis leaves non-targeted and targeted metabolite profiling Pseudomonas syringae pv. tomato (Pst-AvrRpm1) infected adjacent uninfected leaf tissues. While overlap was observed between areas, the profiles these regions differed quantitatively clustering analysis underscores a...

Abstract Programmed cell death (PCD) is essential for several aspects of plant life, including development and stress responses. We recently identified the mips1 mutant Arabidopsis thaliana, which deficient enzyme catalyzing limiting step myo-inositol (MI) synthesis. One most striking features light-dependent formation lesions on leaves due to salicylic acid (SA)-dependent PCD. Here, we a suppressor PCD by screening mutations that abolish phenotype. Our screen hxk1 mutant, mutated in gene...

Medicago (Medicago truncatula) establishes a symbiosis with the rhizobia Sinorhizobium sp, resulting in formation of nodules where bacteria fix atmospheric nitrogen. The loss immunity repression or early senescence activation compromises symbiont survival and leads to nonfunctional (fix-). Despite many studies exploring an overlap between responses outside nodule context, relationship these processes remains poorly understood. To investigate this phenomenon, we selected characterized three...

Nicotiana sylvestris leaves challenged by the bacterial elicitor harpin N(Ea) were used as a model system in which to determine respective roles of light, oxygen, photosynthesis, and respiration programmed cell death response plants. The appearance markers, such membrane damage, nuclear fragmentation, induction stress-responsive element Tnt1, was observed all conditions. However, process delayed dark compared with despite similar accumulation superoxide hydrogen peroxide chloroplasts. In...

The early molecular events underlying the elicitation of plant defence reactions by Gram-positive bacteria are relatively unknown. In plants, calcium and reactive oxygen species commonly involved as cellular messengers a wide range biotic stimuli from pathogenic to symbiotic bacteria. present work, we checked whether nonpathogenic Streptomyces sp. strains could induce signalling leading responses in BY2 tobacco cell suspensions.We have demonstrated that OE7 strain induced cytosolic Ca(2+)...

Summary The establishment of Erwinia amylovora harpin‐induced hypersensitive response (HR) in Nicotiana sylvestris was followed by infra‐red thermography (IRT). Three to four hours after elicitation, the temperature decreased harpin‐infiltrated zone associated stomatal opening. marked drop which reached 2°C and preceded necrosis symptoms for several hours, is thus likely caused higher transpiration. Neither these effects observed a respiratory mutant, affected complex I structure function...

Abstract Medicago truncatula was chosen by the legume community, along with Lotus japonicus , as a model plant to study biology. Since then, numerous resources and tools have been developed for M. . These include, example, its genome sequence, core ecotype collections, transformation/regeneration methods, extensive mutant gene expression atlas. This review aims describe different genetic genomic currently available We also how these were generated provide all information necessary access use...

Losses due to disease and climate change are among the most important issues currently facing crop production. It is therefore establish impact of change, particularly high carbon dioxide (hCO2), on plant immunity in cereals, which provide 60% human calories. The aim this study was determine if hCO2 impacts Brachypodium distachyon immunity, a model for temperate cereals. Plants were grown air (430 ppm CO2) at two CO2 conditions, one that relevant projections within coming century (1000 ppm)...