Phytochrome B enhances seed germination tolerance to high temperature by reducing S-nitrosylation of HFR1.

Light and ambient high temperature (HT) have opposite effects on seed germination. Light induces seed germination through activating the photoreceptor phytochrome B (phyB), resulting in the stabilization of the transcription factor HFR1, which in turn sequesters the suppressor PIF1. HT suppresses seed germination and triggers protein S-nitrosylation. Here, we find that HT suppresses seed germination by inducing the S-nitrosylation of HFR1 at C164, resulting in its degradation, the release of PIF1, and the activation of PIF1-targeted SOMNUS (SOM) expression to alter gibberellin (GA) and abscisic acid (ABA) metabolism. Active phyB (phyBY276H ) antagonizes HFR1 S-nitrosylation and degradation by increasing S-nitrosoglutathione reductase (GSNOR) activity. In line with this, substituting cysteine-164 of HFR1 with serine (HFR1C164S ) abolishes the S-nitrosylation of HFR1 and decreases the HT-induced degradation of HFR1. Taken together, our study suggests that HT and phyB antagonistically modulate the S-nitrosylation level of HFR1 to coordinate seed germination, and provides the possibility to enhance seed thermotolerance through gene-editing of HFR1.

A transcription factor WRKY36 interacts with AFP2 to break primary seed dormancy by progressively silencing DOG1 in Arabidopsis.

The phytohormones abscisic acid (ABA) and gibberellic acid (GA) antagonistically control the shift between seed dormancy and its alleviation. DELAY OF GERMINATION1 (DOG1) is a critical regulator that determines the intensity of primary seed dormancy, but its underlying regulatory mechanism is unclear. In this study, we combined physiological, biochemical, and genetic approaches to reveal that a bHLH transcriptional factor WRKY36 progressively silenced DOG1 expression to break seed dormancy through ABI5-BINDING PROTEIN 2 (AFP2) as the negative regulator of ABA signal. AFP2 interacted with WRKY36, which recognizes the W-BOX in the DOG1 promoter to suppress its expression; Overexpressing WRKY36 broke primary seed dormancy, whereas wrky36 mutants showed strong primary seed dormancy. In addition, AFP2 recruited the transcriptional corepressor TOPLESS-RELATED PROTEIN2 (TPR2) to reduce histone acetylation at the DOG1 locus, ultimately mediating WRKY36-dependent inhibition of DOG1 expression to break primary seed dormancy. Our result proposes that the WRKY36-AFP2-TPR2 module progressively silences DOG1 expression epigenetically, thereby fine-tuning primary seed dormancy.

Temperature-decoupled hydrogen sensing with Pi-shifted fiber Bragg gratings and a partial palladium coating.

A novel, to the best of our knowledge, sensor architecture for palladium-coated fiber Bragg gratings is proposed and demonstrated that allows highly accurate multi-parameter sensing and decoupling of hydrogen concentration from temperature. By means of partly Pd-coated Pi-shifted FBGs (PSFBGs), the notch wavelength of the narrow transmission band and the flank wavelength of the broader reflection band experience different hydrogen and temperature sensitivities. PSFBGs were calibrated at hydrogen concentrations between 800 and 10,000 ppm and temperatures from 20 to 40°C, and a decreased hydrogen sensitivity at increased temperatures was found. Nonlinear temperature-dependent hydrogen calibration functions were therefore determined. An iterative matrix algorithm was used to decouple hydrogen concentration and temperature and to account for the nonlinear calibration functions. Achieved improvements and results have great importance for real field applications of FBG-based hydrogen sensing.

An improved algorithm for resolving overlapping peaks in ion mobility spectrometry and its application to the separation of glycan isomers.

Despite the popularity of ion mobility spectrometry (IMS) for glycan analysis, its limited structural resolution hinders the effective separation of many glycan isomers. This leads to the overlap of IMS peaks, consequently impacting the accurate identification of glycan compositions. To this end, an improved algorithm, namely second-order differentiation combined with a simulated annealing particle swarm optimization algorithm based on sine adaptive weights (DWSA-PSO), was proposed for the separation of overlapping IMS peaks formed by glycan isomers. DWSA-PSO first performed second-order differentiation to automatically determine the number of components in overlapping peaks and exclude impossible single-peak combinations. It then introduced sinusoidal adaptive weights and a simulated annealing mechanism to improve the algorithm's search capability and global optimization performance, thereby enabling accurate and efficient separation of individual peaks. To evaluate the performance of DWSA-PSO and its application to the separation of glycan isomers, multiple sets of overlapping peaks with different degrees of overlap were simulated, and various types of multi-component overlapping peaks were formed using six disaccharide and four trisaccharide isomers. The experimental results consistently demonstrated that the DWSA-PSO algorithm outperformed both the improved particle swarm optimization (IPSO) algorithm and the dynamic inertia weight particle swarm optimization (DIWPSO) algorithm in terms of separation accuracy, running time, and fitness values. In addition, the DWSA-PSO algorithm was successfully applied to the separation of glycan isomers in malt milk beverage. All these results reveal the capability of the DWSA-PSO algorithm to facilitate the accurate identification of glycan isomers.

Transcriptome Analysis of Rice Embryo and Endosperm during Seed Germination.

Seed germination is a complex, multistage developmental process that is an important step in plant development. In this study, RNA-Seq was conducted in the embryo and endosperm of unshelled germinating rice seeds. A total of 14,391 differentially expressed genes (DEGs) were identified between the dry seeds and the germinating seeds. Of these DEGs, 7109 were identified in both the embryo and endosperm, 3953 were embryo specific, and 3329 were endosperm specific. The embryo-specific DEGs were enriched in the plant-hormone signal-transduction pathway, while the endosperm-specific DEGs were enriched in phenylalanine, tyrosine, and tryptophan biosynthesis. We categorized these DEGs into early-, intermediate-, and late-stage genes, as well as consistently responsive genes, which can be enriched in various pathways related to seed germination. Transcription-factor (TF) analysis showed that 643 TFs from 48 families were differentially expressed during seed germination. Moreover, 12 unfolded protein response (UPR) pathway genes were induced by seed germination, and the knockout of OsBiP2 resulted in reduced germination rates compared to the wild type. This study enhances our understanding of gene responses in the embryo and endosperm during seed germination and provides insight into the effects of UPR on seed germination in rice.

Diketopiperazine Modulates Arabidopsis thaliana Root System Architecture by Promoting Interactions of Auxin Receptor TIR1 and IAA7/17 Proteins.

Plants can detect the quorum sensing (QS) signaling molecules of microorganisms, such as amino acids, fat derivatives and diketopiperazines (DKPs), thus allowing the exchange information to promote plant growth and development. Here, we evaluated the effects of 12 synthesized DKPs on Arabidopsis thaliana roots and studied their underlying mechanisms of action. Results showed that, as QS signal molecules, the DKPs promoted lateral root development and root hair formation in A.thaliana to differing degrees. The DKPs enhanced the polar transport of the plant hormone auxin from the shoot to root and triggered the auxin-responsive protein IAA7/17 to decrease the auxin response factor, leading to the accumulation of auxin at the root tip and accelerated root growth. In addition, the DKPs induced the development of lateral roots and root hair in the A. thaliana root system architecture via interference with auxin receptor transporter inhibitor response protein 1 (TIR1). A series of TIR1 sites that potentially interact with DKPs were also predicted using molecular docking analysis. Mutations of these sites inhibited the phosphorylation of TIR1 after DKP treatment, thereby inhibiting lateral root formation, especially TIR1-1 site. This study identified several DKP signal molecules in the QS system that can promote the expression of auxin response factors ARF7/19 via interactions of TIR1 and IAA7/17 proteins, thus promoting plant growth and development.

Insights into glucosinolate accumulation and metabolic pathways in Isatis indigotica Fort.

BACKGROUND: Glucosinolates (GSLs) play important roles in defending against exogenous damage and regulating physiological activities in plants. However, GSL accumulation patterns and molecular regulation mechanisms are largely unknown in Isatis indigotica Fort. RESULTS: Ten GSLs were identified in I. indigotica, and the dominant GSLs were epiprogoitrin (EPI) and indole-3-methyl GSL (I3M), followed by progoitrin (PRO) and gluconapin (GNA). The total GSL content was highest (over 20 µmol/g) in reproductive organs, lowest (less than 1.0 µmol/g) in mature organs, and medium in fresh leaves (2.6 µmol/g) and stems (1.5 µmol/g). In the seed germination process, the total GSL content decreased from 27.2 µmol/g (of seeds) to 2.7 µmol/g (on the 120th day) and then increased to 4.0 µmol/g (180th day). However, the content of indole GSL increased rapidly in the first week after germination and fluctuated between 1.13 µmol/g (28th day) and 2.82 µmol/g (150th day). Under the different elicitor treatments, the total GSL content increased significantly, ranging from 2.9-fold (mechanical damage, 3 h) to 10.7-fold (MeJA, 6 h). Moreover, 132 genes were involved in GSL metabolic pathways. Among them, no homologs of AtCYP79F2 and AtMAM3 were identified, leading to a distinctive GSL profile in I. indigotica. Furthermore, most genes involved in the GSL metabolic pathway were derived from tandem duplication, followed by dispersed duplication and segmental duplication. Purifying selection was observed, although some genes underwent relaxed selection. In addition, three tandem-arrayed GSL-OH genes showed different expression patterns, suggesting possible subfunctionalization during evolution. CONCLUSIONS: Ten different GSLs with their accumulation patterns and 132 genes involved in the GSL metabolic pathway were explored, which laid a foundation for the study of GSL metabolism and regulatory mechanisms in I. indigotica.

A conserved but plant-specific CDK-mediated regulation of DNA replication protein A2 in the precise control of stomatal terminal division.

The R2R3-MYB transcription factor FOUR LIPS (FLP) controls the stomatal terminal division through transcriptional repression of the cell cycle genes CYCLIN-DEPENDENT KINASE (CDK) B1s (CDKB1s), CDKA;1, and CYCLIN A2s (CYCA2s). We mutagenized the weak mutant allele flp-1 seeds with ethylmethane sulfonate and screened out a flp-1 suppressor 1 (fsp1) that suppressed the flp-1 stomatal cluster phenotype. FSP1 encodes RPA2a subunit of Replication Protein A (RPA) complexes that play important roles in DNA replication, recombination, and repair. Here, we show that FSP1/RPA2a functions together with CDKB1s and CYCA2s in restricting stomatal precursor proliferation, ensuring the stomatal terminal division and maintaining a normal guard-cell size and DNA content. Furthermore, we provide direct evidence for the existence of an evolutionarily conserved, but plant-specific, CDK-mediated RPA regulatory pathway. Serine-11 and Serine-21 at the N terminus of RPA2a are CDK phosphorylation target residues. The expression of the phosphorylation-mimic variant RPA2aS11,21/D partially complemented the defective cell division and DNA damage hypersensitivity in cdkb1;1 1;2 mutants. Thus, our study provides a mechanistic understanding of the CDK-mediated phosphorylation of RPA in the precise control of cell cycle and DNA repair in plants.

Discovery and modulation of diterpenoid metabolism improves glandular trichome formation, artemisinin production and stress resilience in Artemisia annua.

Plants synthesize diverse diterpenoids with numerous functions in organ development and stress resistance. However, the role of diterpenoids in glandular trichome (GT) development and GT-localized biosynthesis in plants remains unknown. Here, the identification of 10 diterpene synthases (diTPSs) revealed the diversity of diterpenoid biosynthesis in Artemisia annua. Protein-protein interactions (PPIs) between AaKSL1 and AaCPS2 in the plastids highlighted their potential functions in modulating metabolic flux to gibberellins (GAs) or ent-isopimara-7,15-diene-derived metabolites (IDMs) through metabolic engineering. A phenotypic analysis of transgenic plants suggested a complex repertoire of diterpenoids in Artemisia annua with important roles in GT formation, artemisinin accumulation and stress resilience. Metabolic engineering of diterpenoids simultaneously increased the artemisinin yield and stress resistance. Transcriptome and metabolic profiling suggested that bioactive GA4 /GA1 promote GT formation. Collectively, these results expand our knowledge of diterpenoids and show the potential of diterpenoids to simultaneously improve both the GT-localized metabolite yield and stress resistance, in planta.

AGAMOUS-LIKE67 Cooperates with the Histone Mark Reader EBS to Modulate Seed Germination under High Temperature.

Seed germination is a vital developmental process that is tightly controlled by environmental signals, ensuring germination under favorable conditions. High temperature (HT) suppresses seed germination. This process, known as thermoinhibition, is achieved by activating abscisic acid and inhibiting gibberellic acid biosynthesis. The zinc-finger protein SOMNUS (SOM) participates in thermoinhibition of seed germination by altering gibberellic acid/abscisic acid metabolism, but the underlying regulatory mechanism is poorly understood. In this study, we report that SOM binds to its own promoter and activates its own expression in Arabidopsis (Arabidopsis thaliana) and identify the MADS-box transcription factor AGAMOUS-LIKE67 (AGL67) as a critical player in SOM function, based on its ability to recognize CArG-boxes within the SOM promoter and mediate the trans-activation of SOM under HTs. In addition, AGL67 recruits the histone mark reader EARLY BOLTING IN SHORT DAY (EBS), which recognizes H3K4me3 at SOM chromatin. In response to HTs, AGL67 and EBS are highly enriched around the SOM promoter. The AGL67-EBS complex is also necessary for histone H4K5 acetylation, which activates SOM expression, ultimately inhibiting seed germination. Taken together, our results reveal an essential mechanism in which AGL67 cooperates with the histone mark reader EBS, which bridges the process of H3K4me3 recognition with H4K5 acetylation, thereby epigenetically activating SOM expression to suppress seed germination under HT stress.

The Transcriptome of Cunninghamia lanceolata male/female cone reveal the association between MIKC MADS-box genes and reproductive organs development.

BACKGROUND: Cunninghamia lanceolata (Chinese fir), a member of the conifer family Cupressaceae, is one of the most popular cultivated trees for wood production in China. Continuous research is being performed to improve C. lanceolata breeding values. Given the high rate of seed abortion (one of the reasons being the failure of ovule and pollen development) in C. lanceolata, the proper formation of female/male cones could theoretically increase the number of offspring in future generations. MIKC MADS-box genes are well-known for their roles in the flower/cone development and comprise the typical/atypical floral development model for both angiosperms and gymnosperms. RESULTS: We performed a transcriptomic analysis to find genes differentially expressed between female and male cones at a single, carefully determined developmental stage, focusing on the MIKC MADS-box genes. We finally obtained 47 unique MIKC MADS-box genes from C. lanceolata and divided these genes into separate branches. 27 out of the 47 MIKC MADS-box genes showed differential expression between female and male cones, and most of them were not expressed in leaves. Out of these 27 genes, most B-class genes (AP3/PI) were up-regulated in the male cone, while TM8 genes were up-regulated in the female cone. Then, with no obvious overall preference for AG (class C + D) genes in female/male cones, it seems likely that these genes are involved in the development of both cones. Finally, a small number of genes such as GGM7, SVP, AGL15, that were specifically expressed in female/male cones, making them candidate genes for sex-specific cone development. CONCLUSIONS: Our study identified a number of MIKC MADS-box genes showing differential expression between female and male cones in C. lanceolata, illustrating a potential link of these genes with C. lanceolata cone development. On the basis of this, we postulated a possible cone development model for C. lanceolata. The gene expression library showing differential expression between female and male cones shown here, can be used to discover unknown regulatory networks related to sex-specific cone development in the future.

ABI5-BINDING PROTEIN2 Coordinates CONSTANS to Delay Flowering by Recruiting the Transcriptional Corepressor TPR2.

ABI5-BINDING PROTEIN2 (AFP2) negatively regulates the abscisic acid signal by accelerating ABI5 degradation during seed germination in Arabidopsis (Arabidopsis thaliana). The abscisic acid signal is reported to delay flowering by up-regulating Flowering Locus C expression, but the role of AFP2 in regulating flowering time is unknown. Here, we found that flowering time was markedly delayed and CONSTANS (CO) expression was reduced in a transgenic Arabidopsis line overexpressing AFP2 under LD conditions. Conversely, the loss-of-function afp2 mutant showed slightly earlier flowering, with higher CO expression. These data suggest that AFP2 negatively regulates photoperiod-dependent flowering time by modulating the CO signal. We then found that AFP2 exhibited circadian expression rhythms that peaked during the night. Furthermore, the C-terminus of AFP2 interacted with CO, while its N-terminal ethylene response factor-associated amphiphilic repression motif interacted with the transcriptional corepressor TOPLESS-related protein2 (TPR2). Thus, AFP2 bridges CO and TPR2 to form the CO-AFP2-TPR2 complex. Biochemical and genetic analyses showed that AFP2 mediated CO degradation during the night. AFP2 also recruited histone deacetylase activity at Flowering Locus T chromatin through its interaction with TPR2. Taken together, our results reveal an elaborate mechanism by which AFP2 modulates flowering time through coordinating the activity and stability of CO.

Genome-Wide Identification and Analysis on YUCCA Gene Family in Isatis indigotica Fort. and IiYUCCA6-1 Functional Exploration.

Auxin is one of the most critical hormones in plants. YUCCA (Tryptophan aminotransferase of Arabidopsis (TAA)/YUCCA) enzymes catalyze the key rate-limiting step of the tryptophan-dependent auxin biosynthesis pathway, from IPA (Indole-3-pyruvateacid) to IAA (Indole-3-acetic acid). Here, 13 YUCCA family genes were identified from Isatis indigotica, which were divided into four categories, distributing randomly on chromosomes (2n = 14). The typical and conservative motifs, including the flavin adenine dinucleotide (FAD)-binding motif and flavin-containing monooxygenases (FMO)-identifying sequence, existed in the gene structures. IiYUCCA genes were expressed differently in different organs (roots, stems, leaves, buds, flowers, and siliques) and developmental periods (7, 21, 60, and 150 days after germination). Taking IiYUCCA6-1 as an example, the YUCCA genes functions were discussed. The results showed that IiYUCCA6-1 was sensitive to PEG (polyethylene glycol), cold, wounding, and NaCl treatments. The over-expressed tobacco plants exhibited high auxin performances, and some early auxin response genes (NbIAA8, NbIAA16, NbGH3.1, and NbGH3.6) were upregulated with increased IAA content. In the dark, the contents of total chlorophyll and hydrogen peroxide in the transgenic lines were significantly lower than in the control group, with NbSAG12 downregulated and some delayed leaf senescence characteristics, which delayed the senescence process to a certain extent. The findings provide comprehensive insight into the phylogenetic relationships, chromosomal distributions, and expression patterns and functions of the YUCCA gene family in I. indigotica.

Expression of FRIGIDA in root inhibits flowering in Arabidopsis thaliana.

FRIGIDA (FRI), as the major regulator of flowering time in Arabidopsis accessions, can activate its target FLOWERING LOCUS C (FLC) to delay flowering before vernalization. In addition to FLC, other FRI targets also exist in Arabidopsis. Although leaves sense environmental cues to modulate flowering time, it is not known if roots also regulate the floral transition. In this study, we investigated the spatio-temporal effect of FRI on flowering time. Local expression of FRI in the phloem and leaves activated FLC to delay flowering. Furthermore, we found that local expression of FRI in the roots also delayed flowering by activating other targets, MADS AFFECTING FLOWERING4 (MAF4) and MAF5, in the roots. Graft and genetic experiments revealed that the spatial expression of FRI in the root might generate a mobile signal, which is transmitted from roots to shoot and antagonizes the FT signal to delay flowering. Specifically expressing FRI in the embryo efficiently delayed flowering, even expressing FRI as early as the pro-embryo stage is enough to up-regulate FLC expression to delay flowering. Together, our findings demonstrate the spatio-temporal effect of FRI on delaying flowering, and we propose that root tissue also perceives the flowering signal to fine-tune the flowering time through MAF4/5 as novel targets of FRI.

The glutamate receptors AtGLR1.2 and AtGLR1.3 increase cold tolerance by regulating jasmonate signaling in Arabidopsis thaliana.

Plant glutamate-like receptors (GLRs), which are homologs of mammalian ionotropic glutamate receptors (iGluRs), are thought to be involved in plant growth, development, and environmental stress responses. In this study, we demonstrated that two members of Arabidopsis glutamate-like receptors, AtGLR1.2 and AtGLR1.3, play positive roles in the plant response to cold stress. Genetic and biochemical experiments revealed that exogenous jasmonate could attenuate the cold sensitivity of glr1.2 and glr1.3 mutants, and the overexpression of GLR1.2 or GLR1.3 enhanced cold tolerance by increasing endogenous jasmonate levels under cold stress. In addition, the expression of genes in the CBF/DREB1 signaling pathway was decreased in the glr1.2 and glr1.3 mutants, but was promoted in GLR1.2-OE and GLR1.3-OE transgenic plants compared with the wild-type during cold treatment. Further investigation revealed that AtGLR1.2 and AtGLR1.3 independently drove similar functions without directly interacting. Together, our findings suggest that AtGLR1.2 and 1.3 positively enhance cold tolerance in Arabidopsis by activating endogenous jasmonate accumulation and subsequently promoting the downstream CBF/DREB1 cold response pathway during cold stress.

Functional FRIGIDA allele enhances drought tolerance by regulating the P5CS1 pathway in Arabidopsis thaliana.

Flowering at the right time is important for the reproductive success of plants and their response to environmental stress. In Arabidopsis, a major determinant of natural variation in flowering time is FRIGIDA (FRI). In the present study, we show that overexpression of the functional FRIGIDA gene in wild-type Col background (ColFRI) positively enhances the drought tolerance by activating P5CS1 expression and promoting proline accumulation during water stress. Furthermore, no significant changes in FRI gene and protein expression levels were observed with drought treatment, whereas P5CS1 protein expression significantly increased. In contrast, vernalization treatment efficiently reduced P5CS1 expression levels and resulted in a decrease in drought tolerance in the ColFRI plants. The flc mutants with a functional FRI background also relieved FRI-mediated activation of P5CS1 during drought tolerance. Taken together, our findings reveal the novel function of FRI in enhancing drought resistance through its downstream P5CS1 pathway during water-deficit stress, which is dependent on its target, the FLC gene.

AFP2 as the novel regulator breaks high-temperature-induced seeds secondary dormancy through ABI5 and SOM in Arabidopsis thaliana.

Imbibed seeds monitor environmental and endogenous signals to break dormancy and initiate growth under appropriate conditions. In Arabidopsis thaliana, high temperature (HT) induces secondary seed dormancy, but the underlying mechanism remains unclear. In this study, we found that the abi5-1 mutant was insensitive to high temperature, whereas plants overexpressing ABI5 displayed sensitivity. We then identified ABA-insensitive five-binding protein 2 (AFP2), which interacts with ABI5 and is involved in HT-induced secondary seed dormancy. Under HT stress, the loss-of-function afp2 mutant showed lower seeds germination frequency, reversely, AFP2 overexpressing lines (OE-AFP2) showed high germination frequency. Similar to the abi5 mutant, the crossed OE-AFP2 abi5 or afp2 abi5 lines showed high germination under HT, suggesting that ABI5 is epistatic to AFP2. SOM is reported to negatively regulate seeds germination by altering GA/ABA metabolism, here we found that AFP2 and ABI5 altered SOM transcription. Specifically, overexpressing AFP2 suppressed SOM transcription, resulting in high expression of GA biosynthesis-related genes and low expression of ABA biosynthesis-related genes, ultimately promoting seed germination under HT. Thus, our data demonstrate that AFP2 is a novel regulator to control HT-induced secondary seed dormancy through ABI5 and SOM.

Comparative physiological and proteomic analyses reveal different adaptive strategies by Cymbidium sinense and C. tracyanum to drought.

MAIN CONCLUSION: A terrestrial orchid, Cymbidium sinense appears to utilizes "remedy strategy", while an epiphytic orchid, C. tracyanum , employs a "precaution strategy" to drought stress based on morphological, physiological and proteomic analysis. Drought condition influences plant growth and productivity. Although the mechanism by which plants adapt to this abiotic stress has been studied extensively, the water-adaptive strategies of epiphytes grown in water-limited habitats remain undefined. Here, root and leaf anatomies, dynamic changes in physiological and proteomic responses during periods of drought stress and recovery studied in an epiphytic orchid (Cymbidium tracyanum) and a terrestrial orchid (C. sinense) to investigate their strategies for coping with drought. Compared with C. sinense, C. tracyanum showed stronger drought-resistant adaptive characteristics to drought because its leaves had more negative water potential at turgor loss point and roots had higher proportion of velamen radicum thickness. Although both species demonstrated quick recovery of photosynthesis after stress treatment, they differed in physiological and proteomic responses. We detected and functionally characterized 103 differentially expressed proteins in C. sinense and 104 proteins in C. tracyanum. These proteins were mainly involved in carbon and energy metabolism, photosynthesis, and defense responses. The up-regulated expression of plastid fibrillin may have contributed to the marked accumulation of jasmonates only in stressed C. sinense, while ferredoxin-NADP reductase up-regulation was only found in C. tracyanum which possibly related to the stimulation of cyclic electron flow that is linked with photoprotection. These physiological and proteomic performances suggest distinct adaptive strategies to drought stress between C. sinense (remedy strategy) and C. tracyanum (precaution strategy). Our findings may help improve our understanding about the ecological adaptation of epiphytic orchids.

Hearing Aid Acquisition in Chinese Older Adults With Hearing Loss.

OBJECTIVES: To investigate the prevalence and associated factors of hearing aid acquisition in Chinese older adults. METHODS: We obtained data from a population-based survey on ear and hearing disorders, which was conducted in 4 provinces of China in 2014 to 2015. Trained examiners conducted pure tone audiometry and audiologists further ascertained for hearing loss. We relied on hearing conditions and audiologists' recommendations to identify 1503 participants who needed to wear hearing aids. RESULTS: Among those 1503 participants, the estimated prevalence of hearing aid acquisition was 6.5% (95% confidence interval = 5.3%, 7.8%). Urban residency, having severe hearing loss, understanding hearing aid function, and receiving a hearing test in the past 12 months were associated with elevated prevalence of hearing aid acquisition. The top-3 reported reasons for not acquiring a hearing aid were not understanding its function (25.4%), not needing it (22.3%), and not being able to afford it (21.3%). CONCLUSIONS: Hearing aid use, as a widespread rehabilitation and treatment of hearing loss, remains a big challenge in China. Apart from providing low-cost hearing aids, more efforts should focus on improving hearing knowledge and disseminating information about hearing aid function among older adults.

Hearing loss prevalence and risk factors among older adults in China.

OBJECTIVE: This study aims to investigate the prevalence of hearing loss, and to analyse the major demographics and risk factors that influence the prevalence in older adults of China. DESIGN: Cross-sectional investigation. STUDY SAMPLE: Probability proportionate to size sampling (PPS) was adopted for this survey. Among 45,052 individuals, 6984 older adults (≥60 years) were selected as subjects for this study. RESULTS: The prevalence of hearing loss defined as a speech frequency pure tone average of more than 25 dB HL in the better ear was 58.85%. Age and gender were the factors most strongly associated with hearing loss after multivariate adjustment. Ear disease, diabetes, hypertension, atherosclerosis, noise exposure, and ototoxic drugs were significantly correlated with hearing loss. The largest effects were found for ear disease and noise exposure (OR = 2.83 [95% CI: 2.43-3.29]; OR = 2.59 [95% CI: 1.80-3.72]). CONCLUSIONS: Hearing loss is prevalent in nearly two thirds of adults aged 60 years and older in China population. Chronic diseases, ear disease, and noise are important factors in adults aged 60 years and older.