Insights into Plant Sensory Mechanisms under Abiotic Stresses

Abstract

As sessile organisms, plants cannot survive in harmful environments, such as those characterized by drought, flood, heat, cold, nutrient deficiency, and salt or toxic metal stress. These stressors impair plant growth and development, leading to decreased crop productivity. To induce an appropriate response to abiotic stresses, plants must sense the pertinent stressor at an early stage to initiate precise signal transduction. Here, we provide an overview of recent progress in our understanding of the molecular mechanisms underlying plant abiotic stress sensing. Numerous biomolecules have been found to participate in the process of abiotic stress sensing and function as abiotic stress sensors in plants. Based on their molecular structure, these biomolecules can be divided into four groups: Ca²⁺-permeable channels, receptor-like kinases (RLKs), sphingolipids, and other proteins. This improved knowledge can be used to identify key molecular targets for engineering stress-resilient crops in the field.

Keywords: Ca2+-permeable channels; RLKs; abiotic stresses; crop productivity; sensors; sphingolipids.

Figure 1

Summary of discussed biomolecule function in abiotic stress sensing. Based on molecular structure, the biomolecule function in abiotic stress sensing can be divided into four groups. Group I: Ca²⁺-permeable channels, including hyperosmolarity-gated calcium-permeable channel family of proteins (OSCAs), cyclic-nucleotide-gated calcium channels (CNGCs), ANNEXIN proteins (ANNs), glutamate receptor-like proteins (GLRs), and MID1-COMPLEMENTING ACTIVITY proteins (MCAs); Group II: receptor-like kinases (RLKs), including Catharanthus roseus receptor-like kinase 1-like family proteins (CrRLK1Ls), such as FERONIA (FER), THESEUS1 (THE1), HERCULES1 and 2 (HERK1 and 2), MALE DISCOVERER1-INTERACTING RECEPTOR LIKE KINASE 2/LEUCINE-RICH REPEAT KINASE FAMILY PROTEIN INDUCED BY SALT STRESS (MIK2/LRR-KISS), hydrogen-peroxide-induced Ca²⁺ increases 1 (HPCA1), root meristem growth factor receptors and plant elicitor peptide receptors (RGFRs and PEPRs), and the aluminum ion sensor Al Resistance1 (ALR1); Group III: sphingolipids, including glycosylinositol phosphoceramides (GIPCs); Group IV: other proteins, including chilling tolerance divergence 1 (COLD1), EARLY FLOWERING 3 (ELF3), THERMO-WITH ABA-RESPONSE 1 (TWA1), heat shock proteins (HSPs), phytochrome B (phyB), mechanosensitive channel of small conductance (MscS)-like proteins (MSLs), and two-pore potassium family proteins (TPKs), ethylene response factor (ERF) group VII transcription factors (ERFVIIs), and PLANT CYS OXIDASE 1/2 (PCO1/2). Na⁺: dark blue dot; K⁺: light blue dot; Ca²⁺: red dot; “?”: unknown ions, black dot.