Characteristics of SlCML39, a Tomato Calmodulin-like Gene, and Its Negative Role in High Temperature Tolerance of Arabidopsis thaliana during Germination and Seedling Growth

Abstract

Calmodulin-like (CML) proteins are primary calcium sensors and function in plant growth and response to stress stimuli. However, so far, the function of plant CML proteins, including tomato, is still unclear. Previously, it was found that a tomato (Solanum lycopersicum) CML, here named SlCML39, was significantly induced by high temperature (HT) at transcription level, but its biological function is scarce. In this study, the characteristics of SlCML39 and its role in HT tolerance were studied. SlCML39 encodes a protein of 201 amino acids containing four EF hand motifs. Many cis-acting elements related to plant stress and hormone response appear in the promoter regions of SlCML39. SlCML39 is mainly expressed in the root, stem, and leaf and can be regulated by HT, cold, drought, and salt stresses as well as ABA and H2O2. Furthermore, heterologous overexpression of SlCML39 reduces HT tolerance in Arabidopsis thaliana at the germination and seedling growth stages. To better understand the molecular mechanism of SlCML39, the downstream gene network regulated by SlCML39 under HT was analyzed by RNA-Seq. Interestingly, we found that many genes involved in stress responses as well as ABA signal pathway are down-regulated in the transgenic seedlings under HT stress, such as KIN1, RD29B, RD26, and MAP3K18. Collectively, these data indicate that SlCML39 acts as an important negative regulator in response to HT stress, which might be mediated by the ABA signal pathway.

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

“…In tomato, SlCML37 interacts with proteasome maturation factor SlUMP1 and plays a role in fruit chilling stress tolerance (Tang et al, 2021). SlCML39 acts negatively in high temperature tolerance possibly through ABA signaling pathway (Ding et al, 2021). Overexpression of ShCML44 enhances tolerance to cold, drought and salinity stress by higher antioxidant enzymes activity, less membrane damage, better gas exchange and plant water relations in Solanum habrochaites (Munir et al, 2016).…”

Staying in situ or shifting range under ongoing climate change: A case of an endemic herb in theHimalaya‐HengduanMountains across elevational gradients

“…CaMRLK plays vital roles in protein phosphorylation in eukaryotes, related to high temperature, cold and drought stress in plants (Ding et al, 2021). In addition, we found more complex adaptation in high elevations (>3000 m) including five kinds of genes responsible for the regulation of alpine evolution (Table S3).…”

“…RH38 is a member of the DEAD‐box family primarily involved in abiotic stress, and a study found RH38 having upregulated expression under cold stress but more sensitive to thermal stress in Arabidopsis thaliana (Chen & Peng, 2016). CaMRLK plays vital roles in protein phosphorylation in eukaryotes, related to high temperature, cold and drought stress in plants (Ding et al, 2021). In addition, we found more complex adaptation in high elevations (>3000 m) including five kinds of genes responsible for the regulation of alpine evolution (Table S3).…”

Calcium Signaling and the Response to Heat Shock in Crop Plants

“…The pronounced induction of OsMSR2 expression by HS suggests its involvement in thermotolerance. Furthermore, SlCML39 , a CML gene from tomato, was found to have a negative impact on thermotolerance during germination and seedling growth in A. thaliana [ 94 ]. SlCML39 is expressed in various tissues in tomato plants, including leaves, stems, roots, flowers, and fruits.…”