BackgroundLate embryogenesis abundant (LEA) proteins are involved in protecting higher plants from damage caused by environmental stresses. Foxtail millet (Setaria italica) is an important cereal crop for food and feed in semi-arid areas. However, the molecular mechanisms underlying tolerance to these conditions are not well defined.ResultsHere, we characterized a novel atypical LEA gene named SiLEA14 from foxtail millet. It contains two exons separated by one intron. SiLEA14 was expressed in roots, stems, leaves, inflorescences and seeds at different levels under normal growth conditions. In addition, SiLEA14 was dramatically induced by osmotic stress, NaCl and exogenous abscisic acid. The SiLEA14 protein was localized in the nucleus and the cytoplasm. Overexpression of SiLEA14 improved Escherichia coli growth performance compared with the control under salt stress. To further assess the function of SiLEA14 in plants, transgenic Arabidopsis and foxtail millet plants that overexpressed SiLEA14 were obtained. The transgenic Arabidopsis seedlings showed higher tolerance to salt and osmotic stress than the wild type (WT). Similarly, the transgenic foxtail millet showed improved growth under salt and drought stresses compared with the WT. Taken together, our results indicated that SiLEA14 is a novel atypical LEA protein and plays important roles in resistance to abiotic stresses in plants.ConclusionWe characterized a novel atypical LEA gene SiLEA14 from foxtail millet, which plays important roles in plant abiotic stress resistance. Modification of SiLEA14 expression may improve abiotic stress resistance in agricultural crops.Electronic supplementary materialThe online version of this article (doi:10.1186/s12870-014-0290-7) contains supplementary material, which is available to authorized users.
To establish infection, pathogens deliver effectors into host cells to target immune signaling components, including elements of mitogen-activated protein kinase (MPK) cascades. The virulence function of AvrRpt2, one of the first identified Pseudomonas syringae effectors, involves cleavage of the plant defense regulator, RPM1-INTERACTING PROTEIN4 (RIN4), and interference with plant auxin signaling. We show now that AvrRpt2 specifically suppresses the flagellin-induced phosphorylation of Arabidopsis (Arabidopsis thaliana) MPK4 and MPK11 but not MPK3 or MPK6. This inhibition requires the proteolytic activity of AvrRpt2, is associated with reduced expression of some plant defense genes, and correlates with enhanced pathogen infection in AvrRpt2-expressing transgenic plants. Diverse AvrRpt2-like homologs can be found in some phytopathogens, plant-associated and soil bacteria. Employing these putative bacterial AvrRpt2 homologs and inactive AvrRpt2 variants, we can uncouple the inhibition of MPK4/MPK11 activation from the cleavage of RIN4 and related members from the so-called nitrate-induced family as well as from auxin signaling. Thus, this selective suppression of specific mitogen-activated protein kinases is independent of the previously known AvrRpt2 targets and potentially represents a novel virulence function of AvrRpt2.
Crosstalk between posttranslational modifications, such as ubiquitination and phosphorylation, play key roles in controlling the duration and intensity of signaling events to ensure cellular homeostasis. However, the molecular mechanisms underlying the regulation of negative feedback loops remain poorly understood. Here, we uncover a pathway in Arabidopsis thaliana by which a negative feedback loop involving the E3 ubiquitin ligase PUB22 that dampens the immune response is triggered by MITOGEN-ACTIVATED PROTEIN KINASE3 (MPK3), best known for its function in the activation of signaling. PUB22's stability is controlled by MPK3-mediated phosphorylation of residues localized in and adjacent to the E2 docking domain. We show that phosphorylation is critical for stabilization by inhibiting PUB22 oligomerization and, thus, autoubiquitination. The activity switch allows PUB22 to dampen the immune response. This regulatory mechanism also suggests that autoubiquitination, which is inherent to most single unit E3s in vitro, can function as a self-regulatory mechanism in vivo.
Terpenoid phytoalexins function as defense compound against a broad spectrum of pathogens and pests in the plant kingdom. However, the role of phytoalexin in antiviral defense is still elusive. In this study, we identified the biosynthesis pathway of a sesquiterpenoid phytoalexin, capsidiol 3-acetate as an antiviral response against RNA virus Potato Virus X (PVX) in Nicotiana benthamiana. NbTPS1 and NbEAH genes were found strongly induced by PVX-infection. Enzymatic activity and genetic evidence indicated that both genes were involved in the PVX-induced biosynthesis of capsidiol 3-acetate. NbTPS1- or NbEAH-silenced plant was more susceptible to PVX. The accumulation of capsidiol 3-acetate in PVX-infected plant was partially regulated by jasmonic acid signaling receptor COI1. These findings provide an insight into a novel mechanism of how plant uses the basal arsenal machinery to mount a fight against virus attack even in susceptible species.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.