Cellular Ca²⁺ Signals Generate Defined pH Signatures in Plants

Abstract

Ca 2+ play a key role in cell signaling across organisms. The question of how a simple ion can mediate specific outcomes has spurred research into the role of Ca 2+ signatures and their encoding and decoding machinery. Such studies have frequently focused on Ca 2+ alone and our understanding of how Ca 2+ signaling is integrated with other responses is poor. Using in vivo imaging with different genetically encoded fluorescent sensors in Arabidopsis (Arabidopsis thaliana) cells, we show that Ca 2+ transients do not occur in isolation but are accompanied by pH changes in the cytosol. We estimate the degree of cytosolic acidification at up to 0.25 pH units in response to external ATP in seedling root tips. We validated this pH-Ca 2+ link for distinct stimuli. Our data suggest that the association with pH may be a general feature of Ca 2+ transients that depends on the transient characteristics and the intracellular compartment. These findings suggest a fundamental link between Ca 2+ and pH dynamics in plant cells, generalizing previous observations of their association in growing pollen tubes and root hairs. Ca 2+ signatures act in concert with pH signatures, possibly providing an additional layer of cellular signal transduction to tailor signal specificity.

Pathogen‐inducedpHchanges regulate the growth‐defense balance in plants

“…Alteration of pH transients in distinct cell compartments is a fast cellular signaling event reported in response to stress (Behera et al , ). Therefore, we investigated the influence of pH on the observed Fo5176 effect on roots.…”

“…Consequently, plants reacted with an immediate root growth reduction once the elicitors were added to the imaging media ( Fig 1I and J, Movie EV3), suggesting that a fungal molecule induced the rapid changes in the CSC-microtubule machinery and root growth. Alteration of pH transients in distinct cell compartments is a fast cellular signaling event reported in response to stress (Behera et al, 2018). Therefore, we investigated the influence of pH on the observed Fo5176 effect on roots.…”

Pathogen-induced pH changes regulate the growth-defense balance of plants

“…Alteration of pH transients in distinct cell compartments is a fast cellular signalling event reported in response to stress (Behera et al , 2018) . Therefore we investigated the influence of pH on the observed Fo5176 effect on roots.…”

Dynamic measurement of cytosolic pH and [NO3-] uncovers the role of the vacuolar transporter AtCLCa in the control of cytosolic pH

“…The effect of AtCLCa on cytosolic pH may account for the unexpected defect in stomata closure observed in clca knock-out plants, when its function in loading anions into the vacuole would rather lead to the prediction that it is solely involved in stomata opening (6). In this context, modification of cytosolic pH could be an important component of AtCLCa function, as cytosolic pH is an important parameter in cell signaling (45). Cytosolic pH modifications can modulate ion transport systems and enzymatic reactions to trigger stomata opening or closure.…”