The sensing of stress by a single plant tissue results in the mobilization of numerous systemic signals other parts of the plant.
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Many of the systemic signals triggered by stress in plants propagate from cell-to-cell at several millimeters per second.
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Among the rapid cell-to-cell systemic signals of plants are electric, calcium, reactive oxygen species (ROS), and redox waves.
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Systemic signaling in plants is mediated by a combination of paracrine and juxtacrine signaling pathways that are tightly coordinated.
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Once the systemic signals arrive at their target tissues, they induce in them a state of systemic acquired acclimation, and/or defense that result in the higher resilience of plants to stress.
Abstract
Stress results in the enhanced accumulation of reactive oxygen species (ROS) in plants, altering the redox state of cells and triggering the activation of multiple defense and acclimation mechanisms. In addition to activating ROS and redox responses in tissues that are directly subjected to stress (termed ‘local’ tissues), the sensing of stress in plants triggers different systemic signals that travel to other parts of the plant (termed ‘systemic’ tissues) and activate acclimation and defense mechanisms in them; even before they are subjected to stress. Among the different systemic signals triggered by stress in plants are electric, calcium, ROS, and redox waves that are mobilized in a cell-to-cell fashion from local to systemic tissues over long distances, sometimes at speeds of up to several millimeters per second. Here, we discuss new studies that identified various molecular mechanisms and proteins involved in mediating systemic signals in plants. In addition, we highlight recent studies that are beginning to unravel the mode of integration and hierarchy of the different systemic signals and underline open questions that require further attention. Unraveling the role of ROS and redox in plant stress responses is highly important for the development of climate resilient crops.
