Analysis of abiotic and biotic stress-induced Ca transients in the crop species Solanum tuberosum.

Secondary messengers, such as calcium ions (Ca), are integral parts of a system that transduces environmental stimuli into appropriate cellular responses. Different abiotic and biotic stresses as well as developmental processes trigger temporal increases in cytosolic free Ca levels by an influx from external and internal stores. Stimulus-specificity is obtained by a certain amplitude, duration, oscillation and localisation of the response.

Stress Knowledge Map: A knowledge graph resource for systems biology analysis of plant stress responses.

Stress Knowledge Map (SKM; https://skm.nib.si) is a publicly available resource containing two complementary knowledge graphs that describe the current knowledge of biochemical, signaling, and regulatory molecular interactions in plants: a highly curated model of plant stress signaling (PSS; 543 reactions) and a large comprehensive knowledge network (488 390 interactions).

Organelles and phytohormones: a network of interactions in plant stress responses.

Phytohormones are major signaling components that contribute to nearly all aspects of plant life. They constitute an interconnected communication network to fine-tune growth and development in response to the ever-changing environment. To this end, they have to coordinate with other signaling components, such as reactive oxygen species and calcium signals.

Ascorbate peroxidase postcold regulation of chloroplast NADPH dehydrogenase activity controls cold memory.

Exposure of Arabidopsis (Arabidopsis thaliana) to 4°C imprints a cold memory that modulates gene expression in response to a second (triggering) stress stimulus applied several days later. Comparison of plastid transcriptomes of cold-primed and control plants directly before they were exposed to the triggering stimulus showed downregulation of several subunits of chloroplast NADPH dehydrogenase (NDH) and regulatory subunits of ATP synthase. NDH is, like proton gradient 5 (PGR5)-PGR5-like1 (PGRL1), a thylakoid-embedded, ferredoxin-dependent plastoquinone reductase that protects photosystem I and stabilizes ATP synthesis by cyclic electron transport (CET).

Cold-priming causes dampening of oxylipin biosynthesis and signalling during the early cold- and light-triggering response of Arabidopsis thaliana.

Cold-priming uncouples cold and light regulation of otherwise tightly co-regulated genes. In this study, we focused on the early regulatory processes in Arabidopsis within the first 2 h in cold and in high light after a 5-d lag-phase at 20 °C and 24 h cold-priming at 4 °C. Priming quickly modified gene expression in a trigger-specific manner.

Determining the ROS and the Antioxidant Status of Leaves During Cold Acclimation.

Cold slows down Calvin cycle activity stronger than photosynthetic electron transport, which supports production of reactive oxygen species (ROS). Even under extreme temperature conditions, most ROS are detoxified by the combined action of low-molecular weight antioxidants and antioxidant enzymes. Subsequent regeneration of the low-molecular weight antioxidants by NAD(P)H and thioredoxin/thiol-dependent pathways relaxes the electron pressure in the photosynthetic electron transport chain.

Cold priming uncouples light- and cold-regulation of gene expression in Arabidopsis thaliana.

Background: The majority of stress-sensitive genes responds to cold and high light in the same direction, if plants face the stresses for the first time. As shown recently for a small selection of genes of the core environmental stress response cluster, pre-treatment of Arabidopsis thaliana with a 24 h long 4 °C cold stimulus modifies cold regulation of gene expression for up to a week at 20 °C, although the primary cold effects are reverted within the first 24 h. Such memory-based regulation is called priming.

Preparing plants for improved cold tolerance by priming.

Cold is a major stressor, which limits plant growth and development in many parts of the world, especially in the temperate climate zones. A large number of experimental studies has demonstrated that not only acclimation and entrainment but also the experience of single short stress events of various abiotic or biotic kinds (priming stress) can improve the tolerance of plants to chilling temperatures. This process, called priming, depends on a stress "memory".