Abstract Hydrogen sulfide regulates essential plant processes, including adaptation responses to stress situations, and the best characterized mechanism of action of sulfide consists of the post-translational modification of persulfidation. In this study, we reveal the first persulfidation proteome described in rice including 3443 different persulfidated proteins that participate in a broad range of biological processes and metabolic pathways. In addition, comparative proteomics revealed specific proteins involved in sulfide signaling during drought responses. Several proteins are involved in the maintenance of cellular redox homeostasis, the tricarboxylic acid cycle and energy-related pathways, and ion transmembrane transport and cellular water homeostasis, with the aquaporin family showing the highest differential levels of persulfidation. We revealed that water transport activity is regulated by sulfide which correlates with an increasing level of persulfidation of aquaporins. Our findings emphasize the impact of persulfidation on total ATP levels, fatty acid composition, levels of reactive oxygen species, antioxidant enzymatic activities, and relative water content. Interestingly, the role of persulfidation in aquaporin transport activity as an adaptation response in rice differs from current knowledge of Arabidopsis, which highlights the distinct role of sulfide in improving rice tolerance to drought.
Abstract Background: Switchgrass ( Panicum virgatum L.) is a prime candidate for non-grain-based bioenergy feedstock production. Improved drought tolerance and higher water use efficiency are important for its successful field establishment and production, especially on marginal lands. Aquaporins are key channels and regulators for water transportation and maintenance of cellular water status. In this study, the functional role of an aquaporin gene, PvPIP2;9 , in switchgrass was studied. Results: Expression of PvPIP2;9 was regulated by diurnal oscillation and osmotic stress. Constitutive over-expressing PvPIP2;9 in switchgrass significantly improved its leaf length, plant height, above-ground biomass, biomass protein contents, and cellulose contents in stressed plants. Under 21 days of drought treatment, transgenic plants showed less electrolyte leakage rates, but higher relative water contents, photochemical efficiencies, and chlorophyll contents, indicating that PvPIP2;9 positively regulated plant drought tolerance and water use efficiency. Moreover, expression patterns of all 14 switchgrass PIP2 subfamily genes were checked during the drought treatment, and the result showed that over-expressing PvPIP2;9 also affected transcript levels of most other PIP2 genes. Conclusions: Together, this study showed that improved biomass yield, drought tolerance and higher water use efficiency can be achieved by manipulating the expression level of PvPIP2;9 and also suggested PIP2 subfamily genes were transcriptionally regulated in a coordinated manner.
Hydrogen sulfide (H2S) is a versatile signaling molecule that regulates multiple physiological processes in plants, including growth and development, immunity, and stress response as well. Signaling triggered by H2S is proposed to occur via persulfidation, an oxidative post-translational modification (PTM) of cysteine residues (–SH) to persulfides (–SSH). Notwithstanding the growing body of information for the plant persulfidation proteome, the gap between the molecular mechanism of H2S and physiological functions of protein persulfidation remains large. In this mini-review, we discussed the specific regulatory mechanism of persulfidation on guard cell abscisic acid (ABA) signaling and the possible link of persulfidation, sulfenylation, and S-nitrosylation within the framework of redox-based regulation.
Abstract In this paper, we discuss a stochastic SIR model with saturated incidence rate, which perturbed by log-normal Ornstein-Uhlenbeck (OU) process. The stability of the disease-free equilibriumand endemic equilibrium of deterministic system is initially established. Subsequently, the existenceof unique positive solutions of stochastic systems can be proved through the construction of suitableLyapunov functions. The extinction of stochastic SIR model are demonstrated by introducing thethreshold $R_0^e$. Furthermore, we study the persistence of stochastic SIR model as well as derive itsstationary distribution, and the probability density function around the quasi-endemic equilibrium iscomputed. Finally, theoretical findings are validated through numerical simulations.
Abstract Although aerobic methane (CH 4 ) release from plants leads to an intense scientific and public controversy in the recent years, the potential functions of endogenous CH 4 production in plants are still largely unknown. Here, we reported that polyethylene glycol (PEG)-induced osmotic stress significantly increased CH 4 production and soluble sugar contents in maize ( Zea mays L.) root tissues. These enhancements were more pronounced in the drought stress-tolerant cultivar Zhengdan 958 (ZD958) than in the drought stress-sensitive cultivar Zhongjiangyu No.1 (ZJY1). Exogenously applied 0.65 mM CH 4 not only increased endogenous CH 4 production, but also decreased the contents of thiobarbituric acid reactive substances. PEG-induced water deficit symptoms, such as decreased biomass and relative water contents in both root and shoot tissues, were also alleviated. These beneficial responses paralleled the increases in the contents of soluble sugar and the reduced ascorbic acid (AsA), and the ratio of AsA/dehydroascorbate (DHA). Further comparison of transcript profiles of some key enzymes in sugar and AsA metabolism suggested that CH 4 might participate in sugar signaling, which in turn increased AsA production and recycling. Together, these results suggested that CH 4 might function as a gaseous molecule that enhances osmotic stress tolerance in maize by modulating sugar and AsA metabolism.
Computer-aided design usually gives inspirations and has become a vital strategy to develop novel pesticides through reconstructing natural lead compounds. Patulin, an unsaturated heterocyclic lactone mycotoxin, is a new natural PSII inhibitor and shows significant herbicidal activity to various weeds. However, some evidence, especially the health concern, prevents it from developing as a bioherbicide. In this work, molecular docking and toxicity risk prediction are combined to construct interaction models between the ligand and acceptor, and design and screen novel derivatives. Based on the analysis of a constructed patulin–Arabidopsis D1 protein docking model, in total, 81 derivatives are designed and ranked according to quantitative estimates of drug-likeness (QED) values and free energies. Among the newly designed derivatives, forty-five derivatives with better affinities than patulin are screened to further evaluate their toxicology. Finally, it is indicated that four patulin derivatives, D3, D6, D34, and D67, with higher binding affinity but lower toxicity than patulin have a great potential to develop as new herbicides with improved potency.
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