Exogenous hydrogen sulphide promotes plant flowering through the Arabidopsis splicing factor AtU2AF65a.

Alternative splicing (AS) is an important regulatory mode at the post-transcriptional level, through which many flowering genes regulate floral transition by producing multiple transcripts, and splicing factors have essential roles in this process. Hydrogen sulphide (H2S) is a newly found gasotransmitter that has critical physiological roles in plants, and one of its potential modes of action is via persulfidation of target proteins at specific cysteine sites. Previously, it has been shown that both the splicing factor AtU2AF65a and H2S are involved in the regulation of plant flowering. This study found that, in Arabidopsis, the promoting effect of H2S on flowering was abolished in atu2af65a-4 mutants. Transcriptome analyses showed that when AtU2AF65a contained mutations, the regulatory function of H2S during the AS of many flowering genes (including SPA1, LUH, LUG and MAF3) was inhibited. The persulfidation assay showed that AtU2AF65a can be persulfidated by H2S, and the RNA immunoprecipitation data indicated that H2S could alter the binding affinity of AtU2AF65a to the precursor messenger RNA of the above-mentioned flowering genes. Overall, our results suggest that H2S may regulate the AS of flowering-related genes through persulfidation of splicing factor AtU2AF65a and thus lead to early flowering in plants.

AtPRMT5-mediated AtLCD methylation improves Cd2+ tolerance via increased H2S production in Arabidopsis.

Arabidopsis (Arabidopsis thaliana) PROTEIN ARGININE METHYLTRANSFERASE5 (PRMT5), a highly conserved arginine (Arg) methyltransferase protein, regulates multiple aspects of the growth, development, and environmental stress responses by methylating Arg in histones and some mRNA splicing-related proteins in plants. Hydrogen sulfide (H2S) is a recently characterized gasotransmitter that also regulates various important physiological processes. l-cysteine desulfhydrase (LCD) is a key enzyme of endogenous H2S production. However, our understanding of the upstream regulatory mechanisms of endogenous H2S production is limited in plant cells. Here, we confirmed that AtPRMT5 increases the enzymatic activity of AtLCD through methylation modifications during stress responses. Both atprmt5 and atlcd mutants were sensitive to cadmium (Cd2+), whereas the overexpression (OE) of AtPRMT5 or AtLCD enhanced the Cd2+ tolerance of plants. AtPRMT5 methylated AtLCD at Arg-83, leading to a significant increase in AtLCD enzymatic activity. The Cd2+ sensitivity of atprmt5-2 atlcd double mutants was consistent with that of atlcd plants. When AtPRMT5 was overexpressed in the atlcd mutant, the Cd2+ tolerance of plants was significantly lower than that of AtPRMT5-OE plants in the wild-type background. These results were confirmed in pharmacological experiments. Thus, AtPRMT5 methylation of AtLCD increases its enzymatic activity, thereby strengthening the endogenous H2S signal and ultimately improving plant tolerance to Cd2+ stress. These findings provide further insights into the substrates of AtPRMT5 and increase our understanding of the regulatory mechanism upstream of H2S signals.

Epigenetic Regulation in Response to CO2 Fluctuation in Marine Microalga Nannochloropsis oceanica.

Microalgae often undergo different CO2 experiment in their habitat. To adapt to low CO2, carbon concentrating mechanism (CCM) could be launched in majority of microalgae and CCM are regulated at RNA level are well known. However, epigenetic modifications and their potential regulation of the transcription of masked genes at the genome level in response to CO2 fluctuation remain unclear. Here epigenetic regulation in response to CO2 fluctuation and epigenome-association with phenotypic plasticity of CCM are firstly uncovered in marine microalga Nannochloropsis oceanica IMET1. The result showed that lysine butyrylation (Kbu) and histone H3K9m2 modifications were present in N. oceanica IMET1. Moreover, Kbu modification positively regulated gene expression. In response to CO2 fluctuation, there were 5,438 and 1,106 genes regulated by Kbu and H3K9m2 in Nannochloropsis, respectively. Gained or lost histone methylations were closely associated with activating or repressing gene expressions. Differential modifications were mainly enriched in carbon fixation, photorespiration, photosynthesis, and lipid metabolism etc. Massive genome-wide epigenetic reprogramming was observed after N. oceanica cells shifted from high CO2 to low CO2. Particularly, we firstly noted that the transcription of the key low CO2 responsive carbonic anhydrase (CA5), a key component involved in CCM stress signaling, was potentially regulated by bivalent Kbu-H3K9m2 modifications in microalgae. This study provides novel insights into the relationship between gene transcription and epigenetic modification in Nannochloropsis, which will lay foundation on genetic improvement of CCM at epigenetic level.

Cloning, expression, and functional analysis of the ß-1,3-glucanase gene in Ostrinia furnacalis.

The ß-1,3-glucanase gene in Ostrinia furnacalis was first obtained by RT-PCR. The real-time fluorescence quantitative PCR showed that the expression level of ß-1,3-glucanase in the midgut of O. furnacalis was higher than in other tissues. Moreover, the expression level in the larval stage was higher in egg, pupa, and adult stages. The optimal pH of recombinant O. furnacalis ß-1,3-glucanase OfLam to the substrate laminarin was 4.5, and the optimum reaction temperature was 50°C. The enzyme exhibited a KM of 1.59 ± 0.28 mg/mL and a kcat of 15.8 ± 0.66 s-1 . Ostrinia furnacalis ß-1,3-glucanase has a similar catalytic efficiency to other insect-derived ß-1,3-glucanases. The recombinant OfLam has a broad substrate spectrum and can hydrolyze fungal cell walls, suggesting a new source of enzymes for biological control strategies that target fungal cell walls.

Characterization of the O-acetylserine(thiol)lyase gene family in Solanum lycopersicum L.

KEY MESSAGE: This research demonstrated the conservation and diversification of the functions of the O-acetylserine-(thiol) lyase gene family genes in Solanum lycopersicum L. Cysteine is the first sulfur-containing organic molecule generated by plants and is the precursor of many important biomolecules and defense compounds. Cysteine and its derivatives are also essential in various redox signaling-related processes. O-acetylserine(thiol)lyase (OASTL) proteins catalyze the last step of cysteine biosynthesis. Previously, researches focused mainly on OASTL proteins which were the most abundant or possessed the authentic OASTL activity, whereas few studies have ever given a comprehensive view of the functions of all the OASTL members in one specific species. Here, we characterized 8 genes belonging to the OASTL gene family from tomato genome (SlOAS2 to SlOAS9), including the sequence analyses, subcellular localization, enzymatic activity assays, expression patterns, as well as the interaction property with SATs. Apart from SlOAS3, all the other genes encoded OASTL-like proteins. Tomato OASTLs were differentially expressed during the development of tomato plants, and their encoded proteins had diverse compartmental distributions and functions. SlOAS5 and SlOAS6 catalyzed the biogenesis of cysteine in chloroplasts and in the cytosol, respectively, and this was in consistent with their interaction abilities with SlSATs. SlOAS4 catalyzed the generation of hydrogen sulfide, similar to its Arabidopsis ortholog, DES1. SlOAS2 also functioned as an L-cysteine desulfhydrase, but its expression pattern was very different from that of SlOAS4. Additionally, SlOAS8 might be a ß-cyanoalanine synthase in mitochondria, and the S-sulfocysteine synthase activity appeared lost in tomato plants. SlOAS7 exhibited a transactivational ability in yeast; while the subcellular localization of SlOAS9 was in the peroxisome and correlated with the process of leaf senescence, indicating that these two genes might have novel roles.

The Ca2+ /calmodulin2-binding transcription factor TGA3 elevates LCD expression and H2 S production to bolster Cr6+ tolerance in Arabidopsis.

Heavy metal (HM) contamination on agricultural land not only reduces crop yield but also causes human health concerns. As a plant gasotransmitter, hydrogen sulfide (H2 S) can trigger various defense responses and help reduce accumulation of HMs in plants; however, little is known about the regulatory mechanisms of H2 S signaling. Here, we provide evidence to answer the long-standing question about how H2 S production is elevated in the defense of plants against HM stress. During the response of Arabidopsis to chromium (Cr6+ ) stress, the transcription of L-cysteine desulfhydrase (LCD), the key enzyme for H2 S production, was enhanced through a calcium (Ca2+ )/calmodulin2 (CaM2)-mediated pathway. Biochemistry and molecular biology studies demonstrated that Ca2+ /CaM2 physically interacts with the bZIP transcription factor TGA3, a member of the 'TGACG'-binding factor family, to enhance binding of TGA3 to the LCD promoter and increase LCD transcription, which then promotes the generation of H2 S. Consistent with the roles of TGA3 and CaM2 in activating LCD expression, both cam2 and tga3 loss-of-function mutants have reduced LCD abundance and exhibit increased sensitivity to Cr6+ stress. Accordingly, this study proposes a regulatory pathway for endogenous H2 S generation, indicating that plants respond to Cr6+ stress by adjusting the binding affinity of TGA3 to the LCD promoter, which increases LCD expression and promotes H2 S production. This suggests that manipulation of the endogenous H2 S level through genetic engineering could improve the tolerance of grains to HM stress and increase agricultural production on soil contaminated with HMs.

Regulation of FLOWERING LOCUS T by a microRNA in Brachypodium distachyon.

The highly conserved florigen gene FLOWERING LOCUS T (FT) functions at the core of the flowering pathways. Extensive studies have examined the transcriptional regulation of FT; however, other layers of FT regulation remain unclear. Here, we identified miR5200 a Pooideae-specific microRNA that is expressed in leaves and targets Brachypodium distachyon FT orthologs for mRNA cleavage. miR5200 was abundantly expressed in plants grown under short-day (SD) conditions but was dramatically repressed in plants transferred to long-day (LD) conditions. We also found that the epigenetic chromatin status, specifically the levels of histone methylation marks, at miR5200 precursor loci changed in response to daylength. Moreover, artificial interruption of miR5200 activity by target mimicry in B. distachyon altered flowering time in SD but not in LD conditions, suggesting that miR5200 functions in photoperiod-mediated flowering time regulation. Together, these findings illustrate a posttranscriptional regulation mechanism of FT and provide insights into understanding of the multiple concerted pathways for flowering time control in plants.

The SEPALLATA MADS-box protein SLMBP21 forms protein complexes with JOINTLESS and MACROCALYX as a transcription activator for development of the tomato flower abscission zone.

Organ abscission is a key step in a plant's life cycle and is one of the most important agronomic traits for crops. In tomato, two MADS-box genes, JOINTLESS (J) and MACROCAYLYX (MC), have been shown to be implicated in development of the flower abscission zone (AZ), but the molecular mechanisms underlying this process are not well known. We report here that the SEPALLATA (SEP) MADS-box gene SLMBP21 acts as an additional factor for development of the AZ in tomato. We show that knockdown of SLMBP21 abolishes development of the flower AZ, while overexpression of SLMBP21 produces small cells at the proximal section of the pedicel and the peduncle. Bimolecular fluorescence complementation analysis confirms that SLMBP21 interacts with J and MC, and co-immunoprecipitation assays further demonstrates that these three proteins may form higher-order protein complexes. In situ hybridization shows that SLMBP21, J, and MC transcripts accumulate in distinct regions, but overlap at the AZ vasculature. In addition, transactivation assays in yeast show that, of the three interacting proteins, only SLMBP21 can activate reporter gene transcription. RNA-seq analysis furthermore reveals that loss of function of SLMBP21, J, or MC affects a common subset of meristem activity genes including LeWUS and LATERAL SUPPRESSOR that were specifically expressed in the AZ on the tomato flower pedicel. Since SLMBP21 belongs to the FBP9/23 subclade of the SEP gene family, which is absent in Arabidopsis, the SLMBP21-J-MC complex may represent a distinct mechanism for development of the AZ in plants.

A MADS-box gene NtSVP regulates pedicel elongation by directly suppressing a KNAT1-like KNOX gene NtBPL in tobacco (Nicotiana tabacum L.).

Optimal inflorescence architecture is important for plant reproductive success by affecting the ultimate number of flowers that set fruits and for plant competitiveness when interacting with biotic or abiotic conditions. The pedicel is one of the key contributors to inflorescence architecture diversity. To date, knowledge about the molecular mechanisms of pedicel development is derived from Arabidopsis. Not much is known regarding other plants. Here, an SVP family MADS-box gene, NtSVP, in tobacco (Nicotiana tabacum) that is required for pedicel elongation was identified. It is shown that knockdown of NtSVP by RNA interference (RNAi) caused elongated pedicels, while overexpression resulted in compact inflorescences with much shortened pedicels. Moreover, an Arabidopsis BREVIPEDECELLUS/KNAT1 homologue NtBP-Like (NtBPL) was significantly up-regulated in NtSVP-RNAi plants. Disruption of NtBPL decreased pedicel lengths and shortened cortex cells. Consistent with the presence of a CArG-box at the NtBPL promoter, the direct binding of NtSVP to the NtBPL promoter was demonstrated by yeast one-hybrid assay, electrophoretic mobility shift assay, and dual-luciferase assay, in which NtSVP may act as a repressor of NtBPL. Microarray analysis showed that down-regulation of NtBPL resulted in differential expression of genes associated with a number of hormone biogenesis and signalling genes such as those for auxin and gibberellin. These findings together suggest the function of a MADS-box transcription factor in plant pedicel development, probably via negative regulation of a BP-like class I KNOX gene. The present work thus postulates the conservation and divergence of the molecular regulatory pathways underlying the development of plant inflorescence architecture.

Structural and functional characterization of the actin-1 gene promoter from the Antheraea pernyi (Lepidoptera: Saturniidae).

The Chinese oak silkworm, Antheraea pernyi, is an economically important insect of the Saturniidae family. In this study, genome walking was performed to obtain an A. pernyi actin promoter, which can be employed in transgenic or stable cell line expression systems. The putative promoter was analyzed by the online promoter analysis programs at the Berkeley Drosophila Genome Project and the Web Promoter Scan Service, which led to the recognition of several functional elements. With respect to these elements, a series of actin A1 promoter fragments with 5'-deletions were generated that were then used to construct different vectors expressing Green Fluorescent Protein (GFP). The plasmids were transfected into Sf9 cells and GFP expression was determined by observing GFP fluorescence in cells and by measuring GFP mRNA levels with real-time polymerase chain reaction. Sequence comparisons indicated that the sequence cloned from A. pernyi was the actin A1 promoter. The basic function of the promoter was verified by constructing expression vectors and observing GFP expression. In addition, real-time polymerase chain reaction revealed a strong inhibitory element may exist upstream of the TATA box, which downregulated gene expression. The actin A1 promoter is an ideal candidate for use in A. pernyi transgenic systems.

Genome-editing of a circadian clock gene TaPRR95 facilitates wheat peduncle growth and heading date.

Plant height and heading date are important agronomic traits in wheat (Triticum aestivum L.) that affect final grain yield. In wheat, knowledge of pseudo-response regulator (PRR) genes on agronomic traits is limited. Here, we identify a wheat TaPRR95 gene by genome-wide association study to be associated with plant height. Triple allele mutant plants produced by CRISPR/Cas9 show increased plant height, particularly the peduncle, with an earlier heading date. The longer peduncle is mainly caused by the increased cell elongation at its upper section, whilst the early heading date is accompanied by elevated expression of flowering genes, such as TaFT and TaCO1. A peduncle-specific transcriptome analysis reveals up-regulated photosynthesis genes and down-regulated IAA/Aux genes for auxin signaling in prr95aabbdd plants that may act as a regulatory mechanism to promote robust plant growth. A haplotype analysis identifies a TaPRR95-B haplotype (Hap2) to be closely associated with reduced plant height and increased thousand-grain weight. Moreover, the Hap2 frequency is higher in cultivars than that in landraces, suggesting the artificial selection on the allele during wheat breeding. These findings suggest that TaPRR95 is a regulator for plant height and heading date, thereby providing an important target for wheat yield improvement.

Sclerotic prostate cancer bone metastasis: woven bone lesions with a twist.

Bone metastases are the most severe and prevalent consequences of prostate cancer (PC), affecting more than 80% of patients with advanced PC. PCBMs generate pain, pathological fractures, and paralysis. As modern therapies increase survival, more patients are suffering from these catastrophic consequences. Radiographically, PCBMs are predominantly osteosclerotic, but the mechanisms of abnormal bone formation and how this pathological increase in bone density is related to fractures are unclear. In this study, we conducted a comprehensive analysis on a cohort of 76 cadaveric PCBM specimens and 12 cancer-free specimens as controls. We used micro-computed tomography to determine 3D organization and quantify bone characteristics, quantitative backscattering electron microscopy to characterize mineral content and details in bone structure, nanoindentation to determine mechanical properties, and histological and immunohistochemical analysis of bone structure and composition. We define 4 PCBM phenotypes: osteolytic, mixed lytic-sclerotic, and 2 subgroups of osteosclerotic lesions-those with residual trabeculae, and others without residual trabeculae. The osteosclerotic lesions are characterized by the presence of abnormal bone accumulated on trabeculae surfaces and within intertrabecular spaces. This abnormal bone is characterized by higher lacunae density, abnormal lacunae morphology, and irregular lacunae orientation. However, mineral content, hardness, and elastic modulus at micron-scale were indistinguishable between this irregular bone and residual trabeculae. The collagen matrix of this abnormal bone presents with irregular organization and a prominent collagen III composition. These characteristics suggest that osteosclerotic PCBMs initiate new bone deposition as woven bone; however, the lack of subsequent bone remodeling, absence of lamellar bone deposition on its surface, and presence of collagen III distinguish this pathologic matrix from conventional woven bone. Although the mineralized matrix retains normal bone hardness and stiffness properties, the lack of fibril anisotropy presents a compromised trabecular structure, which may have clinical implications.

Physiological and transcriptome analysis of response of soybean (Glycine max) to cadmium stress under elevated CO2 concentration.

The continuous accumulation of Cd has long-lasting detrimental effects on plant growth and food safety. Although elevated CO2 concentration (EC) has been reported to reduce Cd accumulation and toxicity in plants, evidence on the functions of elevated CO2 concentration and its mechanisms in the possible alleviation of Cd toxicity in soybean are limited. Here, we used physiological and biochemical methods together with transcriptomic comparison to explore the effects of EC on Cd-stressed soybean. Under Cd stress, EC significantly increased the weight of roots and leaves, promoted the accumulations of proline, soluble sugars, and flavonoid. In addition, the enhancement of GSH activity and GST gene expressions promoted Cd detoxification. These defensive mechanisms reduced the contents of Cd2+, MDA, and H2O2 in soybean leaves. The up-regulation of genes encoding phytochelatin synthase, MTPs, NRAMP, and vacuoles protein storage might play vital roles in the transportation and compartmentalization process of Cd. The MAPK and some transcription factors such as bHLH, AP2/ERF, and WRKY showed changed expressions and might be engaged in mediation of stress response. These findings provide a boarder view on the regulatory mechanism of EC on Cd stress and provide numerous potential target genes for future engineering of Cd-tolerant cultivars in soybean breeding programs under climate changes scenarios.

The innate immune sensor STING accelerates neointima formation via NF-κB signaling pathway.

Vascular smooth muscle cells (VSMCs) proliferation, migration, and phenotypic switching are considered crucial events in the progression of neointima formation. Stimulator of interferon genes (STING), an innate immune sensor of cyclic dinucleotides against pathogens, in neointima formation remains obscure. Here, we observed a significant increase in STING expression on the neointima of injured vessels and mouse aortic VSMCs induced by PDGF-BB. In vivo, global knockout of STING (Sting-/-) attenuated neointima formation after vascular injury. In vitro data showed that STING deficiency significantly alleviated PDGF-BB-induced proliferation and migration in VSMCs. Furthermore, these contractile marker genes were upregulated in Sting-/- VSMCs. Overexpression of STING promoted proliferation, migration, and phenotypic switching in VSMCs. Mechanistically, STING-NF-κB signaling was involved in this process. The pharmacological inhibition of STING induced by C-176 partially prevented neointima formation due to suppression of VSMCs proliferation. Taken together, STING-NF-κB axis significantly promoted proliferation, migration, and phenotypic switching of VSMCs, which may be a novel therapeutic approach to combat vascular proliferative diseases.

Identification and expression analysis of genome-wide long noncoding RNA responsive CO2 fluctuated environment in marine microalga Nannochloropsis oceanica.

Long non-coding RNAs (lncRNAs) have been demonstrated to participate in plant growth and development as well as response to different biotic and abiotic stresses. However, the knowledge of lncRNA was limited in microalgae. In this study, by RNA deep sequencing, 134 lncRNAs were identified in marine Nannochloropsis oceanica in response to carbon dioxide fluctuation. Among them, there were 51 lncRNAs displayed differentially expressed between low and high CO2 treatments, including 33 upregulation and 18 downregulation lncRNAs. Cellulose metabolic process, glucan metabolic process, polysaccharide metabolic process, and transmembrane transporter activity were functionally enriched. Multiple potential target genes of lncRNA and lncRNA-mRNA co-located gene network were analyzed. Subsequent analysis had demonstrated that lncRNAs would participate in many biological molecular processes, including gene expression, transcriptional regulation, protein expression and epigenetic regulation. In addition, alternative splicing events were firstly analyzed in response to CO2 fluctuation. There were 2051 alternative splicing (AS events) identified, which might be associated with lncRNA. These observations will provide a novel insight into lncRNA function in Nannochloropsis and provide a series of targets for lncRNA-based gene editing in future.

Identification and functional characterization of a cystathionine ß-lyase (CBL) enzyme for H2S production in Arabidopsis thaliana.

Sulfide or sulfur metabolism plays an important role in the growth and development of plants. Cystathionine ß-lyase (CBL) is an important enzyme in methionine synthesis, but a comprehensive understanding of CBL functions is limited. As the third gasotransmitter, hydrogen sulfide (H2S) plays important physiological roles in plants. In this study, we found that the endogenous H2S content in Arabidopsis thaliana cbl mutants was lower than that in the wild type. Under PEG-based osmotic stress conditions, the H2S contents of CBL-overexpression (OE-CBL) plants increased significantly compared with the wild type. Additionally, the OE-CBL plants increased their tolerance to osmotic stress by increasing the transcription levels of drought-related genes and their relative water-loss rates. Compared with cbl and wild type, OE-CBL plants resisted drought stress by significantly closing their stomata, resulting in improved survival rates. Root tip-bending experiments showed that CBL overexpression relieved osmotic, heavy metal and cold stresses in Arabidopsis. The recombinant CBL activity in vitro revealed that CBL produced H2S using L-cysteine as a substrate. Thus, CBL had a very strong cysteine desulfhydrase activity that could produce endogenous H2S using L-cysteine as a substrate, and it played an important role in plant abiotic stress resistance.

Hydrogen sulfide inhibits the abscission of tomato pedicel through reconstruction of a basipetal auxin gradient.

Abscission is an important developmental process and an essential agricultural trait. Auxin and ethylene are two phytohormones with important roles in the complex, but still elusive signaling network of abscission. Here, we found that hydrogen sulfide (H2S), a newly identified gasotransmitter, inhibits the initiation of tomato pedicel abscission. The underlying mechanism was explored through transcriptome profile analysis in various pedicel tissues with or without H2S treatment in the early abscission stage. The data suggested that H2S strongly influences the global transcription of pedicel tissues, exerts differential expression regulation along the pedicel, and markedly influences both the auxin and ethylene signaling pathways. Computational analysis revealed that H2S reconstructs a basipetal auxin gradient along the pedicel at 4 h after treatment; this finding was further substantiated by the GUS-staining results of DR5::GUS pedicels. The inhibitory effect of H2S to the ethylene signaling pathway might be an indirect action. Moreover, the subtilisin-like proteinase family members involved in the release of peptide signal molecules are critical components of the abscission signaling network downstream of auxin and ethylene.

Functional characterization of the Serine acetyltransferase family genes uncovers the diversification and conservation of cysteine biosynthesis in tomato.

Sulfur-containing compounds are essential for plant development and environmental adaptation, and closely related to the flavor and nutrition of the agricultural products. Cysteine, the first organic sulfur-containing molecule generated in plants, is the precursor for most of these active substances. Serine acetyltransferase (SERAT) catalyzes the rate-limiting step of its formation. However, despite their importance, systematic analyses of these enzymes in individual species, especially in economically important crops, are still limited. Here, The SERAT members (SlSERATs, four in total) were identified and characterized in tomato. Phylogenetically, the four SlSERAT proteins were classified into three subgroups with distinct genomic structures and subcellular localizations. On the function, it was interesting to find that SlSERAT3;1, possessed a high ability to catalyze the formation of OAS, even though it contained a long C-terminus. However, it retained the essential C-terminal Ile, which seems to be a characteristic feature of SERAT3 subfamily members in Solanaceae. Besides, SlSERAT1;1 and SlSERAT2;2 also had high activity levels and their catalyzing abilities were significantly improved by the addition of an OAS-(thiol)-lyase protein. At the transcriptional level, the four SlSERAT genes had distinct expression patterns during tomato plant development. Under abiotic stress conditions, the chloroplast-localized SlSERATs were the main responders, and the SlSERATs adopted different strategies to cope with osmotic, ion toxicity and other stresses. Finally, analyses in the loss-of-function and overexpression lines of SlSERAT1;1 suggested that function redundancy existed in the tomato SERAT members, and the tomato SERAT member was ideal target for S-assimilation manipulating in molecular breeding.

Physical activity positively predicts bone architecture and bone strength in adolescent males and females.

AIMS: Physical activity (PA) has positive effects on bone accrual and geometry in children during growth. However, we do not know how PA influences adaptations in bone architecture during growth. We evaluated the contribution of PA to bone density, architecture and strength in adolescents. METHODS: We used HR-pQCT (XtremeCT, Scanco Medical) to assess cross-sectional moments of inertia [Imin, Imax (mm4)], total bone density (Tt.Dn, mg HA/cm³), total bone area (Tt.Ar, mm²), cortical bone density (Ct.Dn, mg HA/cm³), cortical thickness (Ct.Th, µm), trabecular bone density (Tb.Dn, mg HA/cm³), trabecular number (Tb.N, mm⁻¹) and trabecular thickness (Tb.Th, µm) at the distal tibia in 146 male and 132 female participants (15-20 years). We evaluated the contribution of impact loading PA (ImpactPA) and non-impact loading PA (NoimpactPA) on bone (p < 0.05). RESULTS: ImpactPA explained 10% of variance in Imin (p = 0.000), and 12% of variance in Imax (p = 0.000) in male participants. In male participants, ImpactPA explained 6% of variance in Tt.Ar (p = 0.003). In female participants, ImpactPA explained 4% of variance in Tt.Dn (p = 0.011), 5% of variance in Tb.Dn (p = 0.004) and 8% of variance in Tb.N (p = 0.001). CONCLUSION: Our findings suggest that ImpactPA is significantly associated with bone architecture and bone strength in adolescent males and females.

H2S Persulfidated and Increased Kinase Activity of MPK4 to Response Cold Stress in Arabidopsis.

Hydrogen sulfide (H2S) is a gasotransmitter along with nitric oxide and carbon oxide, which is involved in plant growth and development as well as biotic and abiotic stress resistance. In a previous study, we reported that mitogen-activated protein kinases, especially MPK4, are important downstream components of H2S involved in alleviating cold stress; however the underlying mechanism is unclear. In this study, we determined that the ability of H2S to alleviate cold stress is impaired in mpk4 mutants, but not in the upstream mek2 and crlk1 mutants. MPK4 was basically persulfidated, and NaHS (H2S donor) further increased the persulfidation level of MPK4. MEK2 was not persulfidated by H2S. NaHS treatments increased the MPK4 activity level nearly tenfold. The persulfidation signal of MPK4 did not disappear after eight cystein residues in MPK4 were site-mutated, respectively. Above all, our results suggested that H2S alleviates cold stress directly by persulfidating MPK4 and increasing the MPK4 kinase activity.