Comparative analysis of stress-induced calcium signals in the crop species barley and the model plant Arabidopsis thaliana

Abstract

Background Plants are continuously exposed to changing environmental conditions and biotic attacks that affect plant growth. In crops, the inability to respond appropriately to stress has strong detrimental effects on agricultural production and yield. Ca 2+ signalling plays a fundamental role in the response of plants to most abiotic and biotic stresses. However, research on stimulus-specific Ca 2+ signals has mostly been pursued in Arabidopsis thaliana , while in other species these events are little investigated . Results In this study, we introduced the Ca 2+ reporter-encoding gene APOAEQUORIN into the crop species barley ( Hordeum vulgare ). Measurements of the dynamic changes in [Ca 2+ ] cyt in response to various stimuli such as NaCl, mannitol, H 2 O 2 , and flagellin 22 (flg22) revealed the occurrence of dose- as well as tissue-dependent [Ca 2+ ] cyt transients. Moreover, the Ca 2+ signatures were unique for each stimulus, suggesting the involvement of different Ca 2+ signalling components in the corresponding stress response. Alongside, the barley Ca 2+ signatures were compared to those produced by the phylogenetically distant model plant Arabidopsis. Notable differences in temporal kinetics and dose responses were observed, implying species-specific differences in stress response mechanisms. The plasma membrane Ca 2+ channel blocker La 3+ strongly inhibited the [Ca 2+ ] cyt response to all tested stimuli, indicating a critical role of extracellular Ca 2+ in the induction of stress-associated Ca 2+ signatures in barley. Moreover, by analysing spatio-temporal dynamics of the [Ca 2+ ] cyt transients along the developmental gradient of the barley leaf blade we demonstrate that different parts of the barley leaf show quantitative differences in [Ca 2+ ] cyt transients in response to NaCl and H 2 O 2 . There were only marginal differences in the response to flg22, indicative of developmental stage-dependent Ca 2+ responses specifically to NaCl and H 2 O 2 . Conclusion This study reveals tissue-specific Ca 2+ signals with stimulus-specific kinetics in the crop species barley, as well as quantitative differences al...

Salt-Induced Early Changes in Photosynthesis Activity Caused by Root-to-Shoot Signaling in Potato

“…The propagation of a fast salt-induced Ca 2+ wave in the shoot and an osmolyteinduced Ca 2+ wave with a lower amplitude was demonstrated in other studies [51,52]. The root-to-shoot Ca 2+ signal can be induced in various ways: hyperosmolarity can activate mechanosensitive NSCCs and osmosensor reduced-hyperosmolality-induced-[Ca 2+ ] i -increase 1 (OSCA1) [53,54], as well as NSCCs through the generation of ROS by respiratory burst oxidase homologue (RBOH), which is activated by receptor kinase Feronia via Rho-of-plants (ROP) [55,56].…”

Global transcriptome profiling reveals root- and leaf-specific responses of barley (Hordeum vulgare L.) to H2O2

“…In this study, an analysis of the barley transcriptome in response to H 2 O 2 was performed using next generation sequencing. First, a suitable concentration of H 2 O 2 that was shown to initiate a stress response in barley was selected on basis of previously performed experiments ( Dodd et al., 2010 ; Giridhar et al., 2022 ). An increase in cytosolic Ca 2+ ([Ca 2+ ] cyt ) is one of the first responses of plants to most biotic and abiotic stresses ( Dodd et al., 2010 ) that in turn leads to downstream stimulus-specific cellular responses.…”

“…An increase in cytosolic Ca 2+ ([Ca 2+ ] cyt ) is one of the first responses of plants to most biotic and abiotic stresses ( Dodd et al., 2010 ) that in turn leads to downstream stimulus-specific cellular responses. H 2 O 2 was shown to induce such transient changes of [Ca 2+ ] cyt with 10 mM eliciting the highest response in barley roots and leaves ( Giridhar et al., 2022 ). Staining of intact plants with the ROS indicator H 2 -DCFDA confirmed that the exogenously applied H 2 O 2 penetrated into both organs ( Figures 1B, C , Supplementary Figure 1 ).…”

High robustness of cytosolic glutathione redox potential under combined salt and osmotic stress in barley as revealed by the biosensor Grx1-roGFP2

“…However, while transgenic reporter lines are a standard research tool in other model plants, only few fluorescent reporter lines have been generated to gain insight into barley growth and physiology, as e.g. for auxin and cytokinin signalling (Kirschner et al 2018;Amanda et al 2022) or calcium signatures (Giridhar et al 2022).…”

“…While transgenic sensor lines in the model dicotyledon A. thaliana are in use since more than a decade, the progress in other genetically accessible model plants has only recently started to gain momentum (Kirschner et al 2018; Müller-Schüssele et al 2020; Hipsch et al 2021; Giridhar et al 2022). To start filling this gap in temperate cereal crops, we created transgenic barley lines expressing the genetically-encoded redox biosensor cytosolic Grx1-roGFP2 for E GSH .…”