Central Role of Adenosine 5′-Phosphosulfate Reductase in the Control of Plant Hydrogen Sulfide Metabolism

Abstract

Hydrogen sulfide (H2S) has been postulated to be the third gasotransmitter in both animals and plants after nitric oxide (NO) and carbon monoxide (CO). In this review, the physiological roles of H2S in plant growth, development and responses to biotic, and abiotic stresses are summarized. The enzymes which generate H2S are subjected to tight regulation to produce H2S when needed, contributing to delicate responses of H2S to environmental stimuli. H2S occupies a central position in plant sulfur metabolism as it is the link of inorganic sulfur to the first organic sulfur-containing compound cysteine which is the starting point for the synthesis of methionine, coenzyme A, vitamins, etc. In sulfur assimilation, adenosine 5′-phosphosulfate reductase (APR) is the rate-limiting enzyme with the greatest control over the pathway and probably the generation of H2S which is an essential component in this process. APR is an evolutionarily conserved protein among plants, and two conserved domains PAPS_reductase and Thioredoxin are found in APR. Sulfate reduction including the APR-catalyzing step is carried out in chloroplasts. APR, the key enzyme in sulfur assimilation, is mainly regulated at transcription level by transcription factors in response to sulfur availability and environmental stimuli. The cis-acting elements in the promoter region of all the three APR genes in Solanum lycopersicum suggest that multiple factors such as sulfur starvation, cytokinins, CO2, and pathogens may regulate the expression of SlAPRs. In conclusion, as a critical enzyme in regulating sulfur assimilation, APR is probably critical for H2S generation during plants’ response to diverse environmental factors.

Lack of FIBRILLIN6 in Arabidopsis thaliana affects light acclimation and sulfate metabolism

“…Among the 36 metabolites that were significantly changed (> 1.5fold change; P < 0.05) in fbn6-1 compared with WT, glycine was 1.9-fold increased. Because suppressed APR mRNA expression has been found previously to be caused by increased GSH levels (Koprivova & Kopriva, 2014;Fu et al, 2018), and indeed all three chloroplast-localized APRs were downregulated in fbn6-1 ( Fig. 7c).…”

“…c). Because suppressed APR mRNA expression has been found previously to be caused by increased GSH levels (Koprivova & Kopriva, ; Fu et al , ), and indeed all three chloroplast‐localized APRs were downregulated in fbn6‐1 (Fig. c; Table S5), we speculate that the increased glycine levels in fbn6 might result in increased GSH levels.…”

Stress responsive gene regulation in relation to hydrogen sulfide in plants under abiotic stress

“…). Plants produce H 2 S via photosynthetic sulfate assimilation pathway in chloroplast via SiR but also in the cytosol by desulfhydrase (Fu et al ). Alagarasan and Ramalingam () have characterized the H 2 S gene family in rice after surveying the whole length of 12 rice chromosomes.…”

Consequences of Oxidative Stress on Plant Glycolytic and Respiratory Metabolism

“…Hydrogen sulfide is a gaseous signaling molecule found in both plants and animals. In plants, H 2 S is produced by the sulfur assimilation pathway and L -/ D -cysteine degradation (Fu et al, 2018). High levels of H 2 S can be phytotoxic, but at lower concentrations, H 2 S was demonstrated to play several roles during plant growth and development as well as biotic and abiotic stress response (Zhang et al, 2008; Chen et al, 2011; Shen et al, 2012, 2013).…”