A calmodulin-like protein (CML10) interacts with cytosolic enzymes GSTU8 and FBA6 to regulate cold tolerance

Abstract

Calmodulin-like proteins (CMLs) are Ca2+ sensors involved in plant growth and development as well as adaptation to environmental stresses; however, their roles in plant responses to cold are not well understood. To reveal the role of MsCML10 from alfalfa (Medicago sativa) in regulating cold tolerance, we examined transgenic alfalfa and Medicago truncatula overexpressing MsCML10, MsCML10-RNAi alfalfa, and a M. truncatula cml10-1 mutant and identified MsCML10-interacting proteins. MsCML10 and MtCML10 transcripts were induced by cold treatment. Up-regulation or down-regulation of MsCML10 resulted in increased or decreased cold tolerance, respectively, while cml10-1 showed decreased cold tolerance that was complemented by expressing MsCML10, suggesting that MsCML10 regulates cold tolerance. MsCML10 interacted with glutathione S-transferase (MsGSTU8) and fructose 1,6-biphosphate aldolase (MsFBA6), and the interaction depended on the presence of Ca2+. The altered activities of GST and FBA and levels of ROS and sugars were associated with MsCML10 transcript levels. We propose that MsCML10 decodes the cold-induced Ca2+ signal and regulates cold tolerance through activating MsGSTU8 and MsFBA6, leading to improved maintenance of ROS homeostasis and increased accumulation of sugars for osmoregulation, respectively.

Calmodulin and calmodulin-like gene family in barley: Identification, characterization and expression analyses

“…MtCML42 positively regulates cold tolerance through regulating MtCBF1 and MtCBF4 expression, and regulates flowering time through sequentially downregulation of MtABI5 and upregulation of MtFTa1 (Sun et al, 2021). Alfalfa (Medicago sativa) MsCML10 regulates cold tolerance through activating MsGSTU8 and MsFBA6, leading to improved maintenance of ROS homeostasis and increased accumulation of sugars for osmoregulation, respectively (Yu et al, 2022). MsCML46 enhances tolerance to abiotic stresses through alleviating osmotic stress and oxidative damage in transgenic tobacco (Du et al, 2021).…”

Characterization ofArabidopsisaldolases AtFBA4 and AtFBA5; inhibition by morin and interaction with calmodulin

“…A previous study suggested that M. sativa MsFBA6 interacts with CaM-like 10 protein, MsCML10 (8). To determine whether this property is conserved with the Arabidopsis orthologs, we used in planta split-luciferase (SL) assays to test the interaction between AtFBA4 and AtCML11, the closest respective Arabidopsis orthologs of MsFBA6 and MsCML10.…”

“…A study using Medicago sativa and Medicago truncatula highlighted the increased freezing resistance that resulted from elevated FBA gluconeogenic activity under cold stress (8). This phenomenon was reported to be a consequence of the interaction of M. sativa calmodulin-like 10 (MsCML10) with MsFBA6, leading to enhanced gluconeogenesis and the accumulation of sugars as osmoprotectants (8).…”

“…A study using Medicago sativa and Medicago truncatula highlighted the increased freezing resistance that resulted from elevated FBA gluconeogenic activity under cold stress (8). This phenomenon was reported to be a consequence of the interaction of M. sativa calmodulin-like 10 (MsCML10) with MsFBA6, leading to enhanced gluconeogenesis and the accumulation of sugars as osmoprotectants (8). These observations suggest a possible Ca 2+ -dependent regulation of FBA during abiotic stress response, where compatible solutes help plants acclimate to stresses such as cold, heat, salinity, and drought.…”

“…The main objectives of the current study were to biochemically characterize two Arabidopsis thaliana cytosolic FBA isozymes that have not been previously examined, AtFBA4 and AtFBA5, and to investigate the binding of AtCML11 to AtFBA4. The latter objective was based on a recent report indicating that orthologs of AtCML11 and AtFBA4 in M. sativa , MsCML10 and MsFBA6, respectively, physically interact and impact MsFBA6 activity and the accumulation of compatible solutes during stress (8). Our third objective was to assess whether morin inhibits plant FBA in vitro activity as has been reported for a protozoan FBA (17).…”