Shaping up: Recent advances in the study of plant calcium channels

Nitrate Signaling and Its Role in Regulating Flowering Time in Arabidopsis thaliana

Plant growth is coordinated with the availability of nutrients that ensure its development. Nitrate is a major source of nitrogen (N), an essential macronutrient for plant growth. It also acts as a signaling molecule to modulate gene expression, metabolism, and a variety of physiological processes. Recently, it has become evident that the calcium signal appears to be part of the nitrate signaling pathway. New key players have been discovered and described in Arabidopsis thaliana (Arabidopsis). In addition, knowledge of the molecular mechanisms of how N signaling affects growth and development, such as the nitrate control of the flowering process, is increasing rapidly. Here, we review recent advances in the identification of new components involved in nitrate signal transduction, summarize newly identified mechanisms of nitrate signaling-modulated flowering time in Arabidopsis, and suggest emerging concepts and existing open questions that will hopefully be informative for further discoveries.

Cell Wall Integrity Signaling in Fruit Ripening

Plant cell walls are essential structures for plant growth and development as well as plant adaptation to environmental stresses. Thus, plants have evolved signaling mechanisms to monitor the changes in the cell wall structure, triggering compensatory changes to sustain cell wall integrity (CWI). CWI signaling can be initiated in response to environmental and developmental signals. However, while environmental stress-associated CWI signaling has been extensively studied and reviewed, less attention has been paid to CWI signaling in relation to plant growth and development under normal conditions. Fleshy fruit development and ripening is a unique process in which dramatic alternations occur in cell wall architecture. Emerging evidence suggests that CWI signaling plays a pivotal role in fruit ripening. In this review, we summarize and discuss the CWI signaling in relation to fruit ripening, which will include cell wall fragment signaling, calcium signaling, and NO signaling, as well as Receptor-Like Protein Kinase (RLKs) signaling with an emphasis on the signaling of FERONIA and THESEUS, two members of RLKs that may act as potential CWI sensors in the modulation of hormonal signal origination and transduction in fruit development and ripening.

Identification and Expression Profile Analysis of the OSCA Gene Family Related to Abiotic and Biotic Stress Response in Cucumber

Simple Summary

Hyperosmolality-gated calcium-permeable channels (OSCAs) are calcium nonselective cation channel proteins involved in multiple biological processes. In this work, the members of the OSCA family in cucumber were systematically analyzed, including their sequence characteristics, phylogenetic relationships, conserved motifs, gene structures, promoter regions, and tissue expression patterns. In addition, the effects of different osmotic-related abiotic stresses [salt (NaCl), drought (PEG), and abscisic acid (ABA)] and three biotic stresses [powdery mildew (PM), downy mildew (DM), and root-knot nematode (RKN)] on OSCA family genes were also determined. The results indicated that cucumber OSCA genes play important roles in response to osmotic-related abiotic stresses and pathogen invasion. Overall, this study lays a foundation for research on the biological function and evolutionary process of OSCA family genes in cucumber.

Abstract

Calcium ions are important second messengers, playing an important role in the signal transduction pathways. Hyperosmolality gated calcium-permeable channels (OSCA) gene family members play critical modulating roles in response to osmotic-related abiotic stress as well as other abiotic and biotic stresses, which has been reported in many plant species such as Arabidopsis, rice, maize, and wheat. However, there has been no report about the identification and expression profile of the OSCA genes in cucumber. In this study, a total of nine OSCA genes were identified, which are unevenly distributed on the six chromosomes of cucumber. Phylogenetic analysis revealed that the OSCAs of cucumber, Arabidopsis, rice and maize were clustered into four clades. The motif arrangement of CsOSCAs was strongly conserved, and the CsOSCA genes in each group had similar genetic structure. A total of 11 and 10 types of cis-elements related to hormone and stress, respectively, were identified in the promoter regions of CsOSCA genes. Gene expression analysis indicated that the CsOSCA genes have different expression patterns in various tissues, and some of them were regulated by three osmotic-related abiotic stresses (salt, drought and ABA) and three biotic stresses (powdery mildew, downy mildew, and root-knot nematode). As the first genome-wide identification and characterization of the OSCA gene family in cucumber, this study lays a foundation for research on the biological function and evolutionary process of this gene family, which is of great significance for exploiting stress resistant cucumber varieties.

New Horizons in Plant Cell Signaling

Responding to environmental stimuli with appropriate molecular mechanisms is essential to all life forms and particularly so in sessile organisms such as plants [...].