The Language of Reactive Oxygen Species Signaling in Plants

Abstract

Reactive oxygen species (ROS) are astonishingly versatile molecular species and radicals that are poised at the core of a sophisticated network of signaling pathways of plants and act as core regulator of cell physiology and cellular responses to environment. ROS are continuously generated in plants as an inevitable consequence of redox cascades of aerobic metabolism. In one hand, plants are surfeited with the mechanism to combat reactive oxygen species, in other circumstances, plants appear to purposefully generate (oxidative burst) and exploit ROS or ROS-induced secondary breakdown products for the regulation of almost every aspect of plant biology, from perception of environmental cues to gene expression. The molecular language associated with ROS-mediated signal transduction, leading to modulation in gene expression to be one of the specific early stress response in the acclamatory performance of the plant. They may even act as "second messenger" modulating the activities of specific proteins or expression of genes by changing redox balance of the cell. The network of redox signals orchestrates metabolism for regulating energy production to utilization, interfering with primary signaling agents (hormones) to respond to changing environmental cues at every stage of plant development. The oxidative lipid peroxidation products and the resulting generated products thereof (associated with stress and senescence) also represent "biological signals," which do not require preceding activation of genes. Unlike ROS-induced expression of genes, these lipid peroxidation products produce nonspecific response to a large variety of environmental stresses. The present review explores the specific and nonspecific signaling language of reactive oxygen species in plant acclamatory defense processes, controlled cell death, and development. Special emphasis is given to ROS and redox-regulated gene expression and the role of redox-sensitive proteins in signal transduction event. It also describes the emerging complexity of apparently contradictory roles that ROS play in cellular physiology to ascertain their position in the life of the plant.

The Mitigation Effects of Exogenous Hydrogen Peroxide when Alleviating Seed Germination and Seedling Growth Inhibition on Salinity-Induced Stress in Barley

“…In other words, environmental stresses result in oxidative stress in plants [12], and they are generally considered harmful to plant cells due to the fact that they can cause extreme oxidative damage to biological molecules such as DNA, proteins, and lipids [13], whereas it has been recently discovered that subtoxic concentrations of H 2 O 2 act as the main regulator of plants' responses to environmental stress [14]. Moreover, it functions as a signal molecule [15] in the regulation of plant growth and differentiation [16]. On the other hand, an intracellular increase of ROS under biotic and abiotic stress conditions activates antioxidant enzymes (AOE) such as catalases and peroxidases in the cell [17].…”

Aplicação exógena de quitosana no sistema antioxidante de jaborandi

“…Segundo Lei et al (2011), a quitosana promove maior aumento no anião superóxido, em relação ao peróxido de hidrogênio, principalmente nas primeiras horas após a eliciação. Como tem sido extensivamente documentado que diversas reações metabólicas originam o H 2 O 2 , inclusive espontaneamente, pode-se considerar que, nas folhas de jaborandi, a atividade da SOD não foi indicadora da presença de peróxidos (KARUPPANAPANDIAN et al 2011;BHATTACHARJEE, 2012;BARBOSA et al, 2014).…”

“…As EROs em altas concentrações danificam o sistema de membranas, levando à peroxidação lipídica, culminando na morte celular, enquanto, em baixas concentrações, as ERO S atuam como moléculas sinalizadoras na expressão de genes ligados à defesa e respostas adaptativas, como síntese de lignina (BHATTACHARJEE, 2012;BARBOSA et al, 2014). A eliminação ou detoxificação das EROs em excesso é obtida por um complexo mecanismo de defesa das plantas, que envolve diversas enzimas e produção de substâncias sequestrantes desses radicais (SHARMA et al, 2012).…”

Main Stages of Plant Cellular Response to Heat Stress

“…Как известно, АФК являются продук-тами нормального метаболизма, но при дей-ствии стрессоров их концентрация в клетках и тканях резко возрастает [Mori, Schroeder, 2004;Колупаев, Карпец, 2009;Sharma et al, 2012]. Повышение их уровня в клетках рас-тений играет двойственную роль [Gill, Tuteja, 2010;Suzuki et al, 2011a]: в высоких концен-трациях АФК наносят вред [Scandalios, 2005;Halliwell, 2006], а при умеренном содержании в клетке они выполняют сигнальную функцию [Bhattacharjee, 2012]. При тепловом стрессе АФК генерируются в различных компартмен-тах клеток.…”