Interplay of Environmental Signals in High Altitude Plants

Abstract

Plant growth at high altitudes require adaptation to extreme environmental conditions. High altitude plants experience elevated levels of UV-B irradiation, lower temperatures, and reduced atmospheric pressure, leading to decreased partial pressures of oxygen (O2) and carbon dioxide (CO2). In this study, we will focus on the mechanisms through which plants perceive and respond to light, temperature, O2, and CO2 levels. Additionally, we will explore the unique adaptations of high altitude plants to endure the challenging conditions in such areas. Photoreceptors in plants exhibit diverse responses to specific light wavelengths, each governed by a distinct signaling pathway. These pathways activate different genes, giving rise to specific phenotypic traits. Notably, plants employ their plasma membrane or phase separation to detect temperature variations by monitoring the biochemical properties of the plasma membrane and specific cytoplasmic molecules. Intriguingly, photoreceptors also enable plants to perceive temperature changes, as their activation or deactivation is more pronounced at certain temperatures compared to others. Plants respond to changes in CO2 levels by gauging the concentration of bicarbonate (HCO3-) in cells, which changes in relationship to changes in the partial pressure of CO2. Oxygen on the other hand is sensed through the N-degron pathway of oxygen sensing and the Group VII ETHYLENE RESPONSE FACTORS ERFVIIs. High O2 levels leads to the oxidation of Cys2 amino acid in the ERVIIs, triggering degradation via the N-degron pathway and subsequent repression of hypoxia-related genes. High altitude plants have evolved specific adaptations to thrive in their challenging habitats. These adaptations include heightened UV-B tolerance, optimal temperature and germination cues, increased stomatal density to enhance CO2 uptake, and heightened sensitivity to oxygen to repress hypoxia-related genes. These strategies hold promise for incorporation into staple crops, facilitating crop cultivation at higher altitudes. However, extensive research is necessary before translating these adaptations into practical applications.