• The nonenergy-conserving alternative oxidase (AOX) has been hypothesized to modulate the amount of reactive oxygen species (ROS) and nitrogen (RNS) in plant mitochondria but there is sparse direct planta evidence support this. Laser scanning fluorescent confocal microscopy biochemical methods were used directly estimate leaf concentrations superoxide (O2(-)), nitric oxide (NO), peroxynitrite (ONOO(-)) hydrogen peroxide (H(2)O(2)) wildtype (Wt) tobacco (Nicotiana tabacum) transgenic with...

Previously, we showed that inoculation of tobacco with Pseudomonas syringae incompatible pv. maculicola results in a rapid and persistent burst superoxide (O(2) (-) ) from mitochondria, no change amount mitochondrial alternative oxidase (AOX) induction the hypersensitive response (HR). However, phaseolicola resulted increased AOX, O(2) HR. Here, show transgenic plants unable to induce AOX phaseolicola, there is now strong burst, similar normally seen only maculicola. This interaction did not...

Summary The mitochondrial electron transport chain ( ETC ) includes an alternative oxidase AOX that may control the generation of reactive oxygen species ROS and nitrogen RNS ). act as signaling intermediates in numerous plant processes, including stomatal movement. role controlling concentrations under both steady‐state different stress conditions was evaluated using Nicotiana tabacum plants lacking a result RNA interference. A potential functional implication changes homeostasis also by...

Antarctica is home to an assortment of psychrophilic algae, which have evolved various survival strategies for coping with their frigid environments. Here, we explore Antarctic psychrophily by examining the ∼212 Mb draft nuclear genome green alga Chlamydomonas sp. UWO241, resides within water column a perennially ice-covered, hypersaline lake. Like certain other UWO241 encodes large number (≥37) ice-binding proteins, putatively originating from horizontal gene transfer. Even more striking,...

ABSTRACT We characterized responses of Nicotiana tabacum to pathovars the bacterial pathogen Pseudomonas syringae . These included a compatible response associated with necrotic cell death (pv. tabaci ), an incompatible that hypersensitive (HR) maculicola ) and induced defences but lacked HR phaseolicola ). Signalling molecules (salicylic acid, nitric oxide, H 2 O known induce stress responsive tobacco Aox1a gene [that encodes mitochondrial electron transport chain (ETC) component...

The Antarctic green alga Chlamydomonas sp. UWO 241 (UWO 241) is adapted to permanent low temperatures, hypersalinity, and extreme shade. One of the most striking phenotypes an altered PSI organization constitutive cyclic electron flow (CEF). To date, little attention has been paid CEF during long-term stress acclimation, consequences sustained in are not known. In this study, we combined photobiology, proteomics, metabolomics understand underlying role high-salinity acclimation. High...

Viridiplantae, a diverse group of green plants and alga that have evolved from common ancestor, are unified in their ability to produce use two types chlorophyll (chlorophyll b) capture light energy. In addition its role harvesting, appropriate levels b required for accumulation, assembly, stability harvesting complexes within the photosynthetic apparatus. Chlorophyll is synthesized by enzyme chlorophyllide oxygenase (CAO), Rieske-type mononuclear non-heme iron oxygenase. A regulatory degron...

Summary The objective of this work was to characterize photosynthetic ferredoxin from the Antarctic green alga Chlamydomonas sp. UWO 241, a key enzyme involved in distributing reducing power. We hypothesize that possesses characteristics typical cold‐adapted enzymes, namely increased structural flexibility and high activity at low temperatures, accompanied by stability moderate temperatures. To address objective, we purified 241 characterized temperature dependence its enzymatic protein...

Plant mitochondria are proposed to act as signaling organelles in the orchestration of defense responses biotic stress and acclimation abiotic stress. However, primary signal(s) being generated by then interpreted cell largely unknown. Recently, we showed that generate a sustained burst superoxide (O 2(-)) during particular plant-pathogen interactions. This O 2(-) appears be controlled mitochondrial components influence rates generation scavenging within organelle. The downstream processes...

The Antarctic psychrophile Chlamydomonas sp. UWO241 evolved in a permanently ice-covered lake whose aquatic environment is characterized not only by constant low temperature and high salt but also light during the austral summer coupled with 6 months of complete darkness winter. Since genome indicated presence Stt7 Stl1 protein kinases, we examined phosphorylation state transition phenomenon this psychrophile. Light-dependent [γ-33P]ATP labeling thylakoid membranes from exhibited distinct...

The Antarctic green alga Chlamydomonas sp. UWO241 is an obligate psychrophile that thrives in the cold (4-6°C) but unable to survive at temperatures ≥18°C. Little known how exposure heat affects its physiology or whether it mounts a stress response manner comparable mesophiles. Here, we dissect responses of temperature by examining growth, primary metabolome and transcriptome under steady-state low conditions. In comparison with reinhardtii, constitutively accumulates metabolites proteins...

Cannabis sativa L. is one of the oldest cultivated crops, used for its fiber and medicinal properties. The cannabis plant synthesizes a myriad secondary metabolites, but most valuable products from medical commercial standpoint are cannabinoids. Despite significant advances in elucidating biochemistry genetics that govern cannabinoid accumulation, we still do not have conclusive evidence role these metabolites physiology C. sativa. In line with known functions other protective cannabinoids...

The Antarctic green alga Chlamydomonas priscuii is an obligate psychrophile and emerging model for photosynthetic adaptation to extreme conditions. Endemic the ice-covered Lake Bonney, this thrives at highly unusual light conditions characterized by very low irradiance (<15 μmol m-2 s-1), a narrow wavelength spectrum enriched in blue light, photoperiod. Genome sequencing of C. exposed unusually large genome, with hundreds similar gene duplicates expanded families, some which could be aiding...

Abstract The perennially ice-covered Lake Bonney in Antarctica has been deemed a natural laboratory for studying life at the extreme. Photosynthetic algae dominate lake food webs and are adapted to multitude of extreme conditions including perpetual shading even height austral summer. Here we examine how unique light environment influences physiology two Chlamydomonas species. priscuii is found exclusively deep photic zone where receives very low levels biased blue part spectrum (400-500...