Transcriptional Modulation of Ethylene Response Factor Protein JERF3 in the Oxidative Stress Response Enhances Tolerance of Tobacco Seedlings to Salt, Drought, and Freezing    

Abstract

Abiotic stresses such as drought, cold, and salinity affect normal growth and development in plants. The production and accumulation of reactive oxygen species (ROS) cause oxidative stress under these abiotic conditions. Recent research has elucidated the significant role of ethylene response factor (ERF) proteins in plant adaptation to abiotic stresses. Our earlier functional analysis of an ERF protein, JERF3, indicated that JERF3-expressing tobacco (Nicotiana tabacum) adapts better to salinity in vitro. This article extends that study by showing that transcriptional regulation of JERF3 in the oxidative stress response modulates the increased tolerance to abiotic stresses. First, we confirm that JERF3-expressing tobacco enhances adaptation to drought, freezing, and osmotic stress during germination and seedling development. Then we demonstrate that JERF3-expressing tobacco imparts not only higher expression of osmotic stress genes compared to wild-type tobacco, but also the activation of photosynthetic carbon assimilation/metabolism and oxidative genes. More importantly, this regulation of the expression of oxidative genes subsequently enhances the activities of superoxide dismutase but reduces the content of ROS in tobacco under drought, cold, salt, and abscisic acid treatments. This indicates that JERF3 also modulates the abiotic stress response via the regulation of the oxidative stress response. Further assays indicate that JERF3 activates the expression of reporter genes driven by the osmotic-responsive GCC box, DRE, and CE1 and by oxidative-responsive as-1 in transient assays, suggesting the transcriptional activation of JERF3 in the expression of genes involved in response to oxidative and osmotic stress. Our results therefore establish that JERF3 activates the expression of such genes through transcription, resulting in decreased accumulation of ROS and, in turn, enhanced adaptation to drought, freezing, and salt in tobacco.

Transcriptional Regulation of the Ethylene Response Factor LeERF2 in the Expression of Ethylene Biosynthesis Genes Controls Ethylene Production in Tomato and Tobacco

“…Increasing studies have shown that ERF proteins play many roles in plant responses to biotic and abiotic stresses and in development and metabolism (Chakravarthy et al, 2003;Gutterson and Reuber, 2004;Huang et al, 2004;Wang et al, 2004a;Zhang et al, 2005;Wu et al, 2008). For example, the ERF proteins SHINE and WAX1 are involved in the synthesis of wax in Arabidopsis and alfalfa (Medicago sativa) and enhance tolerance to salt and drought (Aharoni et al, 2004), demonstrating that, in addition to affecting the expression of genes involved in plant responses to stress, the proteins are also involved in the regulation of plant metabolism.…”

Cross Talk between Nitric Oxide and Phytohormones Regulate Plant Development during Abiotic Stresses

“…However, recent studies indicate ET as a stress-signaling hormone that interacts with signaling cascades of other phytohormones to enhance tolerance against various biotic/abiotic stresses [70,86]. Studies involving tobacco seedlings showed that transcriptional activation of ethylene response factor (ERF) in ethylene-signaling process improved salt stress tolerance by decreasing ROS accumulation [89]. Treatment of Arabidopsis callus with 100 mM NaCl triggered the accumulation of NO that promoted ET emission, resulting in increased expression of the plasma membrane H + -ATPase genes [90].…”

The wheat NB‐LRR gene TaRCR1 is required for host defence response to the necrotrophic fungal pathogen Rhizoctonia cerealis

“…An appropriate level of ROS not only can promote cell wall reinforcement and phytoalexin production, but also has a signalling role in mounting a defence response (Quan et al ., 2008). However, the overproduction of ROS may lead to oxidative stress that can damage some cellular compounds including proteins, lipids, carbohydrates and nucleotides of plant cells (Wu et al ., 2008). ROS‐generating enzymes like NADPH‐dependent oxidase (NOX) complex, and various ROS‐scavenging systems, such as peroxidase, ascorbate peroxidase, catalase (CAT) and superoxide dismutase (SOD), are involved in fine‐tuning of ROS levels in the plant cells, resulting in the activation of plant defence responses (Mittler, 2002).…”