Biology subjects

Fichman, Y.

Publications and source records attributed to Fichman, Y..

4 recordsLinked to original sources

bioRxiv2021

Integration of electric, calcium, reactive oxygen species and hydraulic signals during rapid systemic signaling in plants

The sensing of abiotic stress, mechanical injury, or pathogen attack by a single plant tissue results in the activation of systemic signals that travel from the affected tissue to the entire plant, alerting it of an impending stress or pathogen attack. This process is essential for plant survival during stress and is termed systemic signaling. Among the different signals triggered during this process are calcium, electric, reactive oxygen species (ROS) and hydraulic signals. These are thought to propagate at rapid rates through the plant vascular bundles and to regulate many of the systemic processes essential for plant survival. Although the different signals activated during systemic signaling are thought to be interlinked, their coordination and hierarchy remain to be determined. Here, using a combination of advanced whole-plant imaging and hydraulic pressure measurements, we studied the activation of all four systemic signals in wild type and different Arabidopsis thaliana mutants subjected to a local high light (HL) stress or wounding. Our findings reveal that in response to wounding systemic changes in membrane potential, calcium, ROS, and hydraulic pressure are coordinated by glutamate receptor-like (GLR) proteins 3.3 and 3.6, while in response to HL the respiratory burst oxidase homolog D-driven systemic ROS signal could be separated from systemic changes in membrane potential and calcium levels. We further determine that plasmodesmata functions are required for systemic changes in membrane potential, calcium, and ROS during systemic signaling. Our findings shed new light on the different mechanisms that integrate different systemic signals in plants during stress. Significance statementThe ability of plants to transmit a signal from a stressed or wounded tissue to the entire plant, termed systemic signaling, is key to plant survival during conditions of environmental stress. At least four different systemic signals are thought to be involved in this process: electric, calcium, reactive oxygen and hydraulic. However, how are they coordinated and whether they can be stress-specific is mostly unknown. Here we report that different types of stimuli can induce different types of systemic signals that may or may not be linked with each other. We further reveal that hydraulic waves can be actively regulated in plants in response to wounding, and that proteins that regulate plasmodesmata pores play a key role in systemic signaling.

plant biology↗

bioRxiv2020

A systemic whole-plant change in redox levels accompanies the rapid systemic response of Arabidopsis to wounding

Reactive oxygen species (ROS) play a key role in regulating plant responses to different abiotic stresses, wounding and pathogen attack. In addition to triggering responses at the tissues directly subjected to stress, ROS were recently shown to mediate a rapid whole-plant systemic signal, termed the "ROS wave", required for inducing a state of systemic acquired acclimation, or systemic wound response. However, whether the ROS wave that spreads from the local tissues subjected to wounding to the rest of the plant triggers alterations in redox levels, is mostly unknown at present. Here, using a genetically-encoded reporter for cellular glutathione redox changes, roGFP1, we show that the wounding-induced systemic ROS wave in Arabidopsis thaliana is accompanied by a rapid systemic wave of cytosolic redox oxidation, termed a "redox wave". The ROS wave may therefore trigger changes in redox levels in systemic leaves that in turn can trigger transcriptional, metabolic and proteomic changes resulting in acclimation and/or systemic wound responses. One sentence summaryThe wounding-induced reactive oxygen species (ROS) wave is accompanied by a systemic whole-plant redox response.

plant biology↗

bioRxiv2020

Plasmodesmata-localized proteins and reactive oxygen species orchestrate light-induced rapid systemic signaling in Arabidopsis

Systemic signaling and systemic acquired acclimation (SAA) are key to the survival of plants during episodes of abiotic stress. These processes depend on a continuous chain of cell-to-cell signaling events that extends from the initial tissue that senses the stress (local tissue) to the entire plant (systemic tissues). Among the different systemic signaling molecules and processes thought to be involved in this cell-to-cell signaling mechanism are reactive oxygen species (ROS), calcium, electric and hydraulic signals. How these different signals and processes are interlinked, and how they transmit the systemic signal all the way from the local tissue to the entire plant, remain however largely unknown. Here, studying the systemic response of Arabidopsis thaliana to a local treatment of excess light stress, we report that respiratory burst oxidase homolog D (RBOHD)-generated ROS enhance cell-to-cell transport and plasmodesmata (PD) pore size in a process that depends on the function of PD-localized proteins (PDLPs) 1 and 5, promoting the cell-to-cell transport of systemic signals during responses to light stress. We further identify aquaporins, and several different calcium-permeable channels, belonging to the glutamate receptor-like, mechanosensitive small conductance-like, and cyclic nucleotide-gated families, as involved in this process, but determine that their function is primarily required for the maintenance of the signal in each cell along the path of the systemic signal, as well as for the establishment of acclimation at the local and systemic tissues. PD and RBOHD-generated ROS orchestrate therefore light stress-induced rapid cell-to-cell spread of systemic signals in Arabidopsis. One-sentence summaryRespiratory burst oxidase homolog D-generated reactive oxygen species enhance cell-to-cell transport and plasmodesmata (PD) pore size in a process that depends on the function of the PD-localized proteins (PDLPs) 1 and 5, promoting the cell-to-cell transport of rapid systemic signals during the response of Arabidopsis to excess light stress.

plant biology↗

bioRxiv2020

The impact of water deficit and heat stress combination on the molecular response, physiology and seed production of soybean

A combination of drought and heat stress, occurring at the vegetative or reproductive growth phase of many different crops, can have a devastating impact on yield. In soybean (Glycine max), a considerable effort has been made to develop genotypes with enhanced yield production under conditions of drought or heat stress. However, how these genotypes perform in terms of growth, physiological responses and most importantly seed production, under conditions of drought and heat combination is mostly unknown. Here, we studied the impact of water deficit and heat stress combination on the physiology, seed production and yield per plant of two soybean genotypes, Magellan and Plant Introduction (PI) 548313, that differ in their reproductive responses to heat stress. Our findings reveal that although PI 548313 produced more seeds than Magellan under conditions of heat stress, under conditions of water deficit and heat stress combination its seed production decreased. Because number of flowers and pollen germination of PI 548313 remained high under heat or water deficit and heat combination, the reduced seed production exhibited by PI 548313 under the stress combination could be a result of processes that occur at the stigma, ovaries and/or other parts of the flower following pollen germination. HighlightTolerance to heat stress was found not to confer tolerance to a combination of water deficit and heat stress in soybean, highlighting the need for breeding strategies targeting the stress combination.

plant biology↗