The combined effect of handgrip strength and obesity phenotype on the risk of stroke in Chinese middle-aged and elderly: A cohort study.

OBJECTIVE: The aim of this study was to investigate the combined effect of handgrip strength (HGS) and obesity phenotype on the risk of stroke in Chinese middle-aged and elderly people. METHODS: The data was used from the China Health and Retirement Longitudinal Study (CHARLS). Middle-aged and older adults who participated in surveys between 2011 and 2018 were included in the study. They were divided into 4 different types of obesity phenotypes based on obesity and metabolic status: metabolically healthy non-overweight/obesity (MHNO), metabolically healthy overweight/obesity (MHO), metabolically abnormal non-overweight/obesity (MANO), and metabolically abnormal overweight/obesity (MAO). The HGS level was divided into low and high groups according to the median values. Cox proportional risk regression model was used to analyze the joint effect of HGS and obesity phenotype on the risk of stroke among participants. RESULTS: A total of 7904 participants aged 58.89±9.08 years were included in this study. After adjusting for potential confounders, high HGS&MHO (HR=1.86, 95 % CI=1.12-3.09), high HGS&MANO (HR=2.01, 95 %CI=1.42-2.86), high HGS&MAO (HR=2.01, 95 % CI=1.37-2.93), low HGS&MHNO (HR=1.57, 95 % CI=1.00-2.46), low HGS&MHO (HR=2.09, 95 % CI=1.29-3.38), low HGS&MANO (HR=2.02, 95 % CI=1.35-3.03), and low HGS&MAO (HR=2.48, 95 % CI=1.72-3.58) group had significantly higher risks of stroke than the high HGS&MHNO group. CONCLUSION: The coexistence of metabolically unhealthy and low HGS can synergistically increase the risk of stroke in Chinese middle-aged and elderly people.

Transcription factors Pbr3RAV2 and PbrTTG1 regulate pear resistance to Botryosphaeria dothidea via the autophagy pathway.

Pear ring rot, caused by Botryosphaeria dothidea, is the most serious disease of pear (Pyrus spp.) trees. However, the molecular mechanisms underlying pear resistance to B. dothidea remain elusive. Herein, we demonstrated that the pear AuTophagy-related Gene 1a (PbrATG1a) plays a key role in autophagic activity and resistance to B. dothidea. Stable overexpression of PbrATG1a enhanced resistance to B. dothidea in pear calli. Autophagy activity was greater in PbrATG1a overexpressing calli than in WT calli. We used yeast one-hybrid screening to identify a transcription factor, Related to ABI3 and VP1 (Pbr3RAV2), that binds the promoter of PbrATG1a and enhances pear resistance to B. dothidea by regulating autophagic activity. Specifically, overexpression of Pbr3RAV2 enhanced resistance to B. dothidea in pear calli, while transient silencing of Pbr3RAV2 resulted in compromised resistance to B. dothidea in Pyrus betulaefolia. In addition, we identified Transparent Testa Glabra 1 (PbrTTG1), which interacts with Pbr3RAV2. Pathogen infection enhanced the interaction between Pbr3RAV2 and PbrTTG1. The Pbr3RAV2-PbrTTG1 complex increased the binding capacity of Pbr3RAV2 and transcription of PbrATG1a. In addition to providing insights into the molecular mechanisms underlying pear disease resistance, these findings suggest potential genetic targets for enhancing disease resistance in pear.

PbARF19-mediated auxin signaling regulates lignification in pear fruit stone cells.

The stone cells in pear fruits cause rough flesh and low juice, seriously affecting the taste. Lignin has been demonstrated as the main component of stone cells. Auxin, one of the most important plant hormone, regulates most physiological processes in plants including lignification. However, the concentration effect and regulators of auxin on pear fruits stone cell formation remains unclear. Here, endogenous indole-3-acetic acid (IAA) and stone cells were found to be co-localized in lignified cells by immunofluorescence localization analysis. The exogenous treatment of different concentrations of IAA demonstrated that the application of 200 µM IAA significantly reduced stone cell content, while concentrations greater than 500 µM significantly increased stone cell content. Besides, 31 auxin response factors (ARFs) were identified in pear genome. Putative ARFs were predicted as critical regulators involved in the lignification of pear flesh cells by phylogenetic relationship and expression analysis. Furthermore, the negative regulation of PbARF19 on stone cell formation in pear fruit was demonstrated by overexpression in pear fruitlets and Arabidopsis. These results illustrated that the PbARF19-mediated auxin signal plays a critical role in the lignification of pear stone cell by regulating lignin biosynthetic genes. This study provides theoretical and practical guidance for improving fruit quality in pear production.

The PbbHLH62/PbVHA-B1 module confers salt tolerance through modulating intracellular Na+/K+ homeostasis and reactive oxygen species removal in pear.

The vacuolar H+-ATPase (V-ATPase) is a multi-subunit membrane protein complex, which plays pivotal roles in building up an electrochemical H+-gradient across tonoplast, energizing Na+ sequestration into the central vacuole, and enhancing salt stress tolerance in plants. In this study, a B subunit of V-ATPase gene, PbVHA-B1 was discovered and isolated from stress-induced P. betulaefolia combining with RT-PCR method. The RT-qPCR analysis revealed that the expression level of PbVHA-B1 was upregulated by salt, drought, cold, and exogenous ABA treatment. Subcellular localization analyses showed that PbVHA-B1 was located in the cytoplasm and nucleus. Moreover, overexpression of PbVHA-B1 gene noticeably increased the ATPase activity and the tolerance to salt in transgenic Arabidopsis plants. In contrast, knockdown of PbVHA-B1 gene in P.betulaefolia by virus-induced gene silencing had reduced resistance to salt stress. In addition, using yeast one-hybride (Y1H) and yeast two-hybride (Y2H) screens, PbbHLH62, a bHLH transcription factor, was identified as a partner of the PbVHA-B1 promoter and protein. Then, we also found that PbbHLH62 positively regulate the expression of PbVHA-B1 and the ATPase activity after salt stress treatment. These findings provide evidence that PbbHLH62 played a critical role in the salt response. Collectively, our results demonstrate that a PbbHLH62/PbVHA-B1 module plays a positive role in salt tolerance by maintain intracellular ion and ROS homeostasis in pear.

Multi-omics provide insights into the regulation of DNA methylation in pear fruit metabolism.

BACKGROUND: Extensive research has been conducted on fruit development in crops, but the metabolic regulatory networks underlying perennial fruit trees remain poorly understood. To address this knowledge gap, we conduct a comprehensive analysis of the metabolome, proteome, transcriptome, DNA methylome, and small RNAome profiles of pear fruit flesh at 11 developing stages, spanning from fruitlet to ripening. Here, we systematically investigate the metabolic landscape and regulatory network involved. RESULTS: We generate an association database consisting of 439 metabolites and 14,399 genes to elucidate the gene regulatory network of pear flesh metabolism. Interestingly, we detect increased DNA methylation in the promoters of most genes within the database during pear flesh development. Application of a DNA methylation inhibitor to the developing fruit represses chlorophyll degradation in the pericarp and promotes xanthophyll, ß-carotene, and abscisic acid (ABA) accumulation in the flesh. We find the gradual increase in ABA production during pear flesh development is correlated with the expression of several carotenoid pathway genes and multiple transcription factors. Of these transcription factors, the zinc finger protein PbZFP1 is identified as a positive mediator of ABA biosynthesis in pear flesh. Most ABA pathway genes and transcription factors are modified by DNA methylation in the promoters, although some are induced by the DNA methylation inhibitor. These results suggest that DNA methylation inhibits ABA accumulation, which may delay fruit ripening. CONCLUSION: Our findings provide insights into epigenetic regulation of metabolic regulatory networks during pear flesh development, particularly with regard to DNA methylation.

PuNDH9, a subunit of ETC Complex I regulates plant defense by interacting with PuPR1.

NAD+ and NADH play critical roles in energy metabolism, cell death, and gene expression. The NADH-ubiquinone oxidoreductase complex (Complex I) has been long known as a key enzyme in NAD+ and NADH metabolism. In the present study, we found and analyzed a new subunit of Complex I (NDH9), which was isolated from Pyrus ussuriensis combined with RT-PCR. Following infection with A. alternata, RT-qPCR analysis demonstrated an increase in the expression of PuNDH9. Genetic manipulation of PuNDH9 levels suggested that PuNDH9 plays key roles in NADH/NAD+ homeostasis, defense enzyme activities, ROS generation, cell death, gene expression, energy metabolism, and mitochondrial functions during the pear- A. alternata interaction. Furthermore, Y2H, GST-pull down, and a split-luciferase complementation imaging assays revealed that PuNDH9 interacts with PuPR1. We discover that PuNDH9 and PuPR1 synergistically activate defense enzyme activities, ROS accumulation, cell death, and plant defenses. Collectively, our findings reveal that PuNDH9 is likely important for plant defenses.

The transcription factor PbbHLH164 is destabilized by PbRAD23C/D.1 and mediates ethylene biosynthesis during pear fruit ripening.

The phytohormone ethylene plays an important role in climacteric fruit ripening. However, the knowledge on molecular regulation of ethylene biosynthesis remains limited in pear fruit. Herein, a new basic helix-loop-helix transcription factor, PbbHLH164, was identified based on the transcriptome analysis of different developing and ripening fruits of two pear cultivars 'Sucui No. 1' and 'Cuiguan'. PbbHLH164 was more highly expressed in ripening fruit than in developing fruit and positively correlated with ethylene production in both cultivars. PbbHLH164 could directly bind to the promoter of 1-aminocyclopropane-1-carboxylate synthase, PbACS1b, to enhance the expression, leading to the increase of ethylene production and the acceleration of fruit ripening. Interestingly, PbbHLH164 physically interacted with an ubiquitin-like/ubiquitin-associated protein PbRAD23C/D.1, and the interaction of PbbHLH164 with PbRAD23C/D.1 attenuated the function of PbbHLH164 in enhancing the activity of the PbACS1b promoter. Notably, PbRAD23C/D.1 was involved in the degradation of PbbHLH164, and this degradation was inhibited by an ubiquitin proteasome inhibitor MG132. Different from PbbHLH164, PbRAD23C/D.1 was more highly expressed in developing fruit than in ripening fruit of both cultivars. These results suggest that the increase of ethylene production during pear fruit ripening results from the up-regulated expression of PbbHLH164 and the down-regulated expression of PbRAD23C/D.1. This information provided new insights into the molecular regulation of ethylene biosynthesis during fruit ripening.

Physiological and autophagy evaluation of different pear varieties (Pyrus spp.) in response to Botryosphaeria dothidea infection.

Ring rot disease is one of the most common diseases in pear orchards. To better understand the physiology, biochemistry and autophagic changes of different pear varieties after Botryosphaeria dothidea (B.dothidea) infection, we evaluated eight different pear varieties for B. dothidea resistance. The susceptible varieties had larger spot diameters, lower chlorophyll contents and higher malondialdehyde contents than the resistant varieties. In disease-resistant varieties, reactive oxygen species (ROS) levels were relatively lower, while the ROS metabolism (antioxidant enzyme activities and the ascorbic acid-glutathione cycle) was also maintained at higher levels, and it induced a significant upregulation of related gene expression. In addition, autophagy, as an important evaluation index, was found to have more autophagic activity in disease-resistant varieties than in susceptible varieties, suggesting that pathogen infestation drives plants to increase autophagy to defend against pathogens. In summary, the results of this study reveal that different resistant pear varieties enhance plant resistance to the disease through a series of physio-biochemical changes and autophagic activity after inoculation with B. dothidea. This study provides clear physiological and biochemical traits for pear disease resistance selection, potential genetic resources and material basis for pear disease control and disease resistance, breeding and points out the direction for research on the mechanism of pear resistance to B. dothidea.

Self S-RNase reduces the expression of two pollen-specific COBRA genes to inhibit pollen tube growth in pear.

Due to self-incompatibility (SI) prevents self-fertilization, natural or artificial cross-pollination has been conducted in many orchards to stabilize fruit yield. However, it is still puzzled which routes of self S-RNase arresting pollen tube growth. Herein, 17 COBRA genes were isolated from pear genome. Of these genes, the pollen-specifically expressed PbCOB.A.1 and PbCOB.A.2 positively mediates pollen tube growth. The promoters of PbCOB.A.1 and/or PbCOB.A.2 were bound and activated by PbABF.E.2 (an ABRE-binding factor) and PbC2H2.K16.2 (a C2H2-type zinc finger protein). Notably, the expressions of PbCOB.A.1, PbCOB.A.2, and PbC2H2.K16.2 were repressed by self S-RNase, suggesting that self S-RNase reduces the expression of PbCOB.A.1 and PbCOB.A.2 by decreasing the expression of their upstream factors, such as PbC2H2.K16.2, to arrest pollen tube growth. PbCOB.A.1 or PbCOB.A.2 accelerates the growth of pollen tubes treated by self S-RNase, but can hardly affect level of reactive oxygen species and deploymerization of actin cytoskeleton in pollen tubes and cannot physically interact with any reported proteins involved in SI. These results indicate that PbCOB.A.1 and PbCOB.A.2 may not relieve S-RNase toxicity in incompatible pollen tube. The information provides a new route to elucidate the arresting pollen tube growth during SI reaction.

PusALDH1 gene confers high levels of volatile aroma accumulation in both pear and tomato fruits.

Aroma is an important commercial trait that determines fruit quality and has an important influence on the overall flavor of fruits. Plant ALDH genes have been implicated in diverse pathways and play crucial roles in physiological activities. In this study, via genome resequencing we identified one gene PusALDH1 (Pbr034873.1) related to aroma biosynthesis that can respond to the induction of methyl jasmonate. Transient transformation of pear fruits and heterologous stable transformation of tomato further confirmed the function of PusALDH1 in aroma accumulation. The content of ALDH precursor substance, benzaldehyde, was reduced in the overexpressing pear and tomato fruits, and the content of ALDH product, benzoic acid and benzoic acid derivatives, was increased in the pear fruits. Meanwhile, transgenic tomato fruits with PusALDH1 overexpression exhibited a greater area of yellow placenta, indicating that the gene may be related to the growth and development of the fruit. Taken together, PusALDH1 could act as a strong candidate gene in aroma synthesis.

Genome-wide identification, comparative analysis and functional roles in flavonoid biosynthesis of cytochrome P450 superfamily in pear (Pyrus spp.).

BACKGROUND: The cytochrome P450 (CYP) superfamily is the largest enzyme metabolism family in plants identified to date, and it is involved in many biological processes, including secondary metabolite biosynthesis, hormone metabolism and stress resistance. However, the P450 gene superfamily has not been well studied in pear (Pyrus spp.). RESULTS: Here, the comprehensive identification and a comparative analysis of P450 superfamily members were conducted in cultivated and wild pear genomes. In total, 338, 299 and 419 P450 genes were identified in Chinese white pear, European pear and the wild pear, respectively. Based on the phylogenetic analyses, pear P450 genes were divided into ten clans, comprising 48 families. The motif and gene structure analyses further supported this classification. The expansion of the pear P450 gene family was attributed to whole-genome and single-gene duplication events. Several P450 gene clusters were detected, which have resulted from tandem and proximal duplications. Purifying selection was the major force imposed on the long-term evolution of P450 genes. Gene dosage balance, subfunctionalization and neofunctionalization jointly drove the retention and functional diversification of P450 gene pairs. Based on the association analysis between transcriptome expression profiles and flavonoid content during fruit development, three candidate genes were identified as being closely associated with the flavonoid biosynthesis, and the expression of one gene was further verified using qRT-PCR and its function was validated through transient transformation in pear fruit. CONCLUSIONS: The study results provide insights into the evolution and biological functions of P450 genes in pear.

PbrChiA: a key chitinase of pear in response to Botryosphaeria dothidea infection by interacting with PbrLYK1b2 and down-regulating ROS accumulation.

Pear ring rot, caused by the pathogenic fungi Botryosphaeria dothidea, seriously affects pear production. While the infection-induced reactive oxygen species (ROS) burst of infected plants limits the proliferation of B. dothidea during the early infection stage, high ROS levels can also contribute to their growth during the later necrotrophic infection stage. Therefore, it is important to understand how plants balance ROS levels and resistance to pathogenic B. dothidea during the later stage. In this study, we identified PbrChiA, a glycosyl hydrolases 18 (GH18) chitinase-encoding gene with high infection-induced expression, through a comparative transcriptome analysis. Artificial substitution, stable overexpression, and virus induced gene silencing (VIGS) experiments demonstrated that PbrChiA can positively regulate pear resistance as a secreted chitinase to break down B. dothidea mycelium in vitro and that overexpression of PbrChiA suppressed infection-induced ROS accumulation. Further analysis revealed that PbrChiA can bind to the ectodomain of PbrLYK1b2, and this interaction suppressed PbrLYK1b2-mediated chitin-induced ROS accumulation. Collectively, we propose that the combination of higher antifungal activity from abundant PbrChiA and lower ROS levels during later necrotrophic infection stage confer resistance of pear against B. dothidea.

The dynamic changes of mango (Mangifera indica L.) epicuticular wax during fruit development and effect of epicuticular wax on Colletotrichum gloeosporioides invasion.

Mango fruits are susceptible to diseases, such as anthracnose, during fruit development, leading to yield reduction. Epicuticular wax is closely related to resistance of plants to pathogenic bacterial invasion. In this study, the effect of mango fruit epicuticular wax on the invasion of Colletotrichum gloeosporioides was investigated, followed by to understand the changes of wax chemical composition and crystal morphology during mango fruit development using GC-MS and SEM. Results showed that the epicuticular wax of mango fruits can prevent the invasion of C. gloeosporioides, and 'Renong' showed the strongest resistance to C. gloeosporioides. The wax content of four mango varieties first increased and then decreased from 40 days after full bloom (DAFB) to 120 DAFB. In addition, 95 compounds were detected in the epicuticular wax of the four mango varieties at five developmental periods, in which primary alcohols, terpenoids and esters were the main wax chemical composition. Furthermore, the surface wax structure of mango fruit changed dynamically during fruit development, and irregular platelet-like crystals were the main wax structure. The present study showed the changes of wax content, chemical composition and crystal morphology during mango fruit development, and the special terpenoids (squalene, farnesyl acetate and farnesol) and dense crystal structure in the epicuticular wax of 'Renong' fruit may be the main reason for its stronger resistance to C. gloeosporioides than other varieties. Therefore, these results provide a reference for the follow-up study of mango fruit epicuticular wax synthesis mechanism and breeding.

PbPDCB16-mediated callose deposition affects the plasmodesmata blockage and reduces lignification in pear fruit.

Stone cell, a type of lignified cell, is a unique trait in pear and one of the key factors affects pear fruit quality and economic value. The transmissibility of cell lignification process has been proven to exist, however the effects of callose on the permeability of plasmodesmata (PD) and how to influence cell lignification processes are still unknown. In this study, the genome-wide analysis of PD callose binding proteins (PDCB) gene family in pear genome was performed, and 25 PbPDCB genes were identified and divided into four branches. Similar intron/exon structural patterns were observed in the same branch, strongly supporting their close evolutionary relationship. The expression of PbPDCB16 was negatively correlated with lignin accumulation through qRT-PCR analysis. With transient expression in pear fruit and stable expression in pear calli, the increased callose content accompanied by decreased lignin content was further observed. Besides, compared with wild type Arabidopsis, the transgenic plants grew slowly, and cell walls in the stem were thinner, while fewer PDs were observed on the cell walls, and the interspore filaments were also blocked in transgenic Arabidopsis through the transmission electron microscope (TEM). In summary, overexpression of PbPDCB16 could promote accumulation of callose at PD to affect the PD-mediated intercellular connectivity, and inhibit the intercellular communication. This study will provide new insight in reducing the lignin content through callose deposition, and also provide the theoretical basis for further exploration of lignin metabolism and cell wall lignification to form stone cells in pear fruit.

Transcription factor PbbZIP4 is targeted for proteasome-mediated degradation by the ubiquitin ligase PbATL18 to influence pear's resistance to Colletotrichum fructicola by regulating the expression of PbNPR3.

Pear anthracnose caused by Colletotrichum fructicola is one of the main fungal diseases in all pear-producing areas. The degradation of ubiquitinated proteins by the 26S proteasome is a regulatory mechanism of eukaryotes. E3 ubiquitin ligase is substrate specific and is one of the most diversified and abundant enzymes in the regulation mechanism of plant ubiquitination. Although numerous studies in other plants have shown that the degradation of ubiquitinated proteins by the 26S proteasome is closely related to plant immunity, there are limited studies on them in pear trees. Here, we found that an E3 ubiquitin ligase, PbATL18, interacts with and ubiquitinates the transcription factor PbbZIP4, and this process is enhanced by C. fructicola infection. PbATL18 overexpression in pear callus enhanced resistance to C. fructicola infection, whereas PbbZIP4 overexpression increased sensitivity to C. fructicola infection. Silencing PbATL18 and PbbZIP4 in Pyrus betulaefolia seedlings resulted in opposite effects, with PbbZIP4 silencing enhancing resistance to C. fructicola infection and PbATL18 silencing increasing sensitivity to C. fructicola infection. Using yeast one-hybrid screens, an electrophoretic mobility shift assay, and dual-luciferase assays, we demonstrated that the transcription factor PbbZIP4 upregulated the expression of PbNPR3 by directly binding to its promoter. PbNPR3 is one of the key genes in the salicylic acid (SA) signal transduction pathway that can inhibit SA signal transduction. Here, we proposed a PbATL18-PbbZIP4-PbNPR3-SA model for plant response to C. fructicola infection. PbbZIP4 was ubiquitinated by PbATL18 and degraded by the 26S proteasome, which decreased the expression of PbNPR3 and promoted SA signal transduction, thereby enhancing plant C. fructicola resistance. Our study provides new insights into the molecular mechanism of pear response to C. fructicola infection, which can serve as a theoretical basis for breeding superior disease-resistant pear varieties.

Weekend warrior physical activity pattern is associated with lower depression risk: Findings from NHANES 2007-2018.

OBJECTIVE: This study aimed to explore the association between weekend warrior physical activity (PA) pattern and depression risk in American adults. METHODS: Data of adults (n = 21,125) from NHANES 2007-2018 were used. Adults were categorized into 4 PA patterns (inactive, insufficiently active, weekend warrior, and regularly active) by self-reported PA levels. Participant characteristics in different groups were tested using the Rao & Scott adjusted χ2 test. Multivariate logistic regression models with adjustment for demographics data, behavioral factors and health condition were used to explore the association between PA patterns and depression risk. Finally, interaction analyses were conducted to test if the associations differ by gender, age, race, education level, income level and marital status. RESULTS: Multivariate logistic regression models showed that insufficiently active, weekend warrior and regularly active adults had 31% (OR: 0.69, 95%CI:0.54-0.88), 57% (OR: 0.43, 95%CI:0.25-0.74) and 54% (OR: 0.46, 95%CI:0.39-0.54) reduced depression risk when compared with inactive adults, respectively. When compared with regularly active adults, inactive (OR: 2.188, 95%CI:1.842-2.600) and insufficiently active (OR: 1.505, 95%CI:1.159-1.955) adults had elevated depression risk, but no significant difference was found between weekend warrior (OR: 0.949, 95%CI:0.538-1.675) and regularly active adults. Moreover, the associations did not differ by demographic variables. CONCLUSIONS: This study showed that adults who engaged in either regularly active pattern or weekend warrior pattern, experienced lower risk of depression compared to inactive adults. Weekend warrior and regularly active patterns showed similar benefits for lowering depression risk in adults, encouraging adults to take up PA in limited sessions.

PearMODB: a multiomics database for pear (Pyrus) genomics, genetics and breeding study.

Pear (Pyrus ssp.) belongs to Rosaceae and is an important fruit tree widely cultivated around the world. Currently, challenges to cope with the burgeoning sets of multiomics data are rapidly increasing. Here, we constructed the Pear Multiomics Database (PearMODB) by integrating genome, transcriptome, epigenome and population variation data, and aimed to provide a portal for accessing and analyzing pear multiomics data. A variety of online tools were built including gene search, BLAST, JBrowse, expression heatmap, synteny analysis and primer design. The information of DNA methylation sites and single-nucleotide polymorphisms can be retrieved through the custom JBrowse, providing an opportunity to explore the genetic polymorphisms linked to phenotype variation. Moreover, different gene families involving transcription factors, transcription regulators and disease resistance (nucleotide-binding site leucine-rich repeat) were identified and compiled for quick search. In particular, biosynthetic gene clusters (BGCs) were identified in pear genomes, and specialized webpages were set up to show detailed information of BGCs, laying a foundation for studying metabolic diversity among different pear varieties. Overall, PearMODB provides an important platform for pear genomics, genetics and breeding studies. Database URL http://pearomics.njau.edu.cn.

Sleep duration and depressive symptoms in Chinese middle-aged and older adults: The moderating effects of grip strength.

BACKGROUND: Evidence on the combined effect of sleep duration and grip strength on depressive symptoms is scarce. This study aimed to explore the moderating effect of grip strength on the association between sleep duration and depressive symptoms in a large cohort of middle-aged and older adults. METHOD: Data were extracted from the China Health and Retirement Longitudinal Study (CHARLS) 2011-2018 wave. Grip strength and sleep duration were assessed by dynamometer and self-report, respectively. Depressive symptoms were determined by the Centre for Epidemiological Studies Depression scale (CESD-10). Multivariable cox regression model was used to explore the associations between sleep duration, and depressive symptoms, and assess moderation by grip strength. RESULTS: A total of 4337 participants aged 57.0 ± 8.1 years (45.1 % females) were included in this study. During the 7-year follow up period, 1508 participants developed depressive symptoms. Short sleep duration (<6 h/d) was significantly associated with an increased risk of depressive symptoms [Hazard ratio (HR):1.24, 95 % confidence interval (CI):1.09, 1.40)]. This association remained in individuals with the low (HR:1.22, 95%CI:1.00, 1.49) and middle grip strength (HR:1.32, 95%CI: 1.07, 1.63), but attenuated in individuals with high grip strength (HR:1.11, 95%CI: 0.86, 1.43). CONCLUSIONS: High grip strength mitigated the association between short sleep duration and higher risk of depressive symptoms. Thus, improving sleep duration and strengthening muscle strength are recommended to prevent depressive symptoms in middle-aged and older adults.

Acetylation of inorganic pyrophosphatase by S-RNase signaling induces pollen tube tip swelling by repressing pectin methylesterase.

Self-incompatibility (SI) is a widespread genetically determined system in flowering plants that prevents self-fertilization to promote gene flow and limit inbreeding. S-RNase-based SI is characterized by the arrest of pollen tube growth through the pistil. Arrested pollen tubes show disrupted polarized growth and swollen tips, but the underlying molecular mechanism is largely unknown. Here, we demonstrate that the swelling at the tips of incompatible pollen tubes in pear (Pyrus bretschneideri [Pbr]) is mediated by the SI-induced acetylation of the soluble inorganic pyrophosphatase (PPA) PbrPPA5. Acetylation at Lys-42 of PbrPPA5 by the acetyltransferase GCN5-related N-acetyltransferase 1 (GNAT1) drives accumulation of PbrPPA5 in the nucleus, where it binds to the transcription factor PbrbZIP77, forming a transcriptional repression complex that inhibits the expression of the pectin methylesterase (PME) gene PbrPME44. The function of PbrPPA5 as a transcriptional repressor does not require its PPA activity. Downregulating PbrPME44 resulted in increased levels of methyl-esterified pectins in growing pollen tubes, leading to swelling at their tips. These observations suggest a mechanism for PbrPPA5-driven swelling at the tips of pollen tubes during the SI response. The targets of PbrPPA5 include genes encoding cell wall-modifying enzymes, which are essential for building a continuous sustainable mechanical structure for pollen tube growth.