Risk and related factors of elbow musculoskeletal diseases: A nationwide cross-sectional survey in China.

OBJECTIVE: Although studies have shown that Work-related Musculoskeletal Disorders (WMSDs) are common and continue to be a main source of disability and work time loss, there are few reports on elbow WMSDs. The aim of this study was to explore the prevalence and associated factors of elbow WMSDs. METHODS: The valid questionnaires of 57501 workers from 15 different industries nationwide were collected and the Chi-square test and logistic-regression-analysis were applied to reveal the prevalence and risk factors of elbow. RESULTS: The findings indicated that prevalence of elbow WMSDs among workers was 7.3%. The prevalence of elbow WMSDs in toy manufacturing was 21.3%, which significantly higher than that in other industries (P<0.05). Logistic regression analysis showed that aged 40 and above, married, very poor health, left-handed, lifting weights (more than 20 kg each time) , work requiring upper limb or hand force, work in an uncomfortable position, repetitive operations within one minute, using vibrating tools, work involves cold, cool winds or temperature changes, work being completed in the same workshop, work being done outdoors, frequent deal with customers , two shifts, often work overtime, staff shortage, often work for colleagues were the risk factors of elbow WMSDs.The higer education level and monthly income, and enough rest time were the protective factors of elbow WMSDs. CONCLUSION: The toy manufacturing is a high-risk industry for elbow WMSDs. The publicity and education of ergonomics knowledge should be strengthened, and the workers' ergonomics awareness should be improved to reduce the impact of WMSDs.

SlGAD2 is the target of SlTHM27, positively regulates cold tolerance by mediating anthocyanin biosynthesis in tomato.

Cold stress significantly limits the yield and quality of tomato. Deciphering the key genes related to cold tolerance is important for selecting and breeding superior cold-tolerant varieties. γ-aminobutyric acid (GABA) responds to various types of stress by rapidly accumulating in plant. In this study, glutamic acid decarboxylase (GAD2) was a positive regulator to enhance cold stress tolerance of tomato. Overexpression of SlGAD2 decreased the extent of cytoplasmic membrane damage and increased the endogenous GABA content, antioxidant enzyme activities, and reactive oxygen species (ROS) scavenging capacity in response to cold stress, whereas Slgad2 mutant plants showed the opposite trend. In addition, SlGAD2 induced anthocyanin biosynthesis in response to cold stress by increasing the content of endogenous GABA. Further study revealed that SlGAD2 expression was negatively regulated by the transcription factor SlTHM27. However, the transcript levels of SlTHM27 were repressed under cold stress. Antioxidant enzyme activities, SlGAD2 transcript levels, GABA and anthocyanin contents were significantly increased in Slthm27 mutant plants. Further, our study demonstrated that SlTHM27 decreases SlGAD2-promoted cold resistance in tomato by repressing SlGAD2 transcription. Overall, our results showed that the SlTHM27-SlGAD2 model regulates the cold tolerance in tomato by regulating GABA and anthocyanin.

Overexpression of SlWRKY6 enhances drought tolerance by strengthening antioxidant defense and stomatal closure via ABA signaling in Solanum lycopersicum L.

Drought is a major handicap for plant growth and development. WRKY proteins comprise one of the largest families of plant transcription factors, playing important roles in plant growth and stress tolerance. In tomato (Solanum lycopersicum L.), different WRKY transcription factors differentially (positively or negatively) regulate drought tolerance, however, the role of SlWRKY6 in drought response and the associated molecular mechanisms of stress tolerance remain unclear. Here we report that SlWRKY6, a member of the WRKYII-b group, is involved in the functional aspects of drought resistance in tomato. Transcriptional activation assays show that SlWRKY6 is transcriptionally active in yeast cells, while the subcellular localization assay indicates that SlWRKY6 is localized in the nucleus. Overexpression of SlWRKY6 in tomato plants resulted in stronger antioxidant capacity and drought resistance as manifested by increased photosynthetic capacity and decreased reactive oxygen species accumulation, malondialdehyde content and relative electrolyte leakage in transgenic tomato plants compared with wild-type under drought stress. Moreover, increased abscisic acid (ABA) content and transcript abundance of ABA synthesis and signaling genes (NCED1, NCED4, PYL4, AREB1 and SnRK2.6) in the transgenic tomato plants indicated potential involvement of the ABA pathway in SlWRKY6-induced drought resistance in tomato plants. Inspection of 2-kb sequences upstream of the predicted binding sites in the promoter of SlNCED1/4 identified two copies of the core W-box (TTGACC/T) sequence in the promoter of SlNCED1/4, which correlates well with the expression of these genes in response to drought, further suggesting the involvement of ABA-dependent pathway in SlWRKY6-induced drought resistance. The study unveils a critical role of SlWRKY6, which can be useful to further reveal the drought tolerance mechanism and breeding of drought-resistant tomato varieties for sustainable vegetable production in the era of climate change.

Exogenous 5-Aminolevulinic acid improved low-temperature tolerance tomato seedling by regulating starch content and phenylalanine metabolism.

Tomato is an important horticultural cash crop, and low-temperature stress has seriously affected the yield and quality of tomato. 5-Aminolevulinic acid (ALA) is widely used in agriculture as an efficient and harmless growth regulator. It is currently unclear whether exogenous ALA can cope with low-temperature stress by regulating tomato starch content and phenylalanine metabolism. In this study, exogenous ALA remarkably improved the low-temperature tolerance of tomato seedlings. RNA-sequencing results showed that exogenous ALA affected starch metabolism and phenylalanine metabolism in tomato seedling leaves under low-temperature stress. Subsequently, we used histochemical staining, observation of chloroplast microstructure, substance content determination, and qRT-PCR analysis to demonstrate that exogenous ALA could improve the low-temperature tolerance of tomato seedlings by regulating starch content and phenylalanine metabolism (SlPAL, SlPOD1, and SlPOD2). Simultaneously, we found that exogenous ALA induced the expression of SlMYBs and SlWRKYs under low-temperature stress. In addition, dual luciferase, yeast one hybrid, and electrophoretic mobility shift assays indicate that SlMYB4 and SlMYB88 could regulate the expression of SlPOD2 in phenylalanine metabolism. We demonstrated that exogenous ALA could improve the low-temperature tolerance of tomato seedlings by regulating starch content and phenylalanine metabolism.

[Develop the rural ecology in the New Era]. / 发展新时代的乡村生态学.

Rural ecology is a comprehensive field of study that takes the rural social-ecological-economic systems as the objective object and emphasizes spatial carrier governance. The development of rural ecology in the New Era embodies and implements comprehensively the core concepts of Xi Jinping Thought on Socialism with Chinese Cha-racteristics for a New Era, including harmonious coexistence between humans and nature, rural revitalization, green development, and the comprehensive construction of a socialist modernized nation. Under the goal of Chinese-style modernization, rural ecology exhibits characteristics distinct from the past, such as the integration of research objects, the intersectionality of basic theories, the computational feature of technical methods, and the orientation of exporting outcomes. To provide disciplinary support for modernization-oriented science to meet the new demands of country's rural development, effectively narrating the story of sustainable rural development in China and providing fundamental guarantees for the safety of rural systems, a number of issues such as paradigm innovation in research, improvement of data quality, and integration of comprehensive technologies, should be fully considered.

5-Aminolevulinic acid improves cold resistance through regulation of SlMYB4/SlMYB88-SlGSTU43 module to scavenge reactive oxygen species in tomato.

Cold stress severely affects the growth and quality of tomato. 5-Aminolevulinic acid (ALA) can effectively improve tomato's cold stress tolerance. In this study, a tomato glutathione S-transferase gene, SlGSTU43, was identified. Results showed that ALA strongly induced the expression of SlGSTU43 under cold stress. SlGSTU43-overexpressing lines showed increased resistance to cold stress through an enhanced ability to scavenge reactive oxygen species. On the contrary, slgstu43 mutant lines were sensitive to cold stress, and ALA did not improve their cold stress tolerance. Thus, SlGSTU43 is a key gene in the process of ALA improving tomato cold tolerance. Through yeast library screening, SlMYB4 and SlMYB88 were preliminarily identified as transcription factors that bind to the SlGSTU43 promoter. Electrophoretic mobility shift, yeast one-hybrid, dual luciferase, and chromatin immunoprecipitation assays experiments verified that SlMYB4 and SlMYB88 can bind to the SlGSTU43 promoter. Further experiments showed that SlMYB4 and SlMYB88 are involved in the process of ALA-improving tomato's cold stress tolerance and they positively regulate the expression of SlGSTU43. The findings provide new insights into the mechanism by which ALA improves cold stress tolerance. SlGSTU43, as a valuable gene, could be added to the cold-responsive gene repository. Subsequently, it could be used in genetic engineering to enhance the cold tolerance of tomato.

SlBEL11 regulates flavonoid biosynthesis, thus fine-tuning auxin efflux to prevent premature fruit drop in tomato.

Auxin regulates flower and fruit abscission, but how developmental signals mediate auxin transport in abscission remains unclear. Here, we reveal the role of the transcription factor BEL1-LIKE HOMEODOMAIN11 (SlBEL11) in regulating auxin transport during abscission in tomato (Solanum lycopersicum). SlBEL11 is highly expressed in the fruit abscission zone, and its expression increases during fruit development. Knockdown of SlBEL11 expression by RNA interference (RNAi) caused premature fruit drop at the breaker (Br) and 3 d post-breaker (Br+3) stages of fruit development. Transcriptome and metabolome analysis of SlBEL11-RNAi lines revealed impaired flavonoid biosynthesis and decreased levels of most flavonoids, especially quercetin, which functions as an auxin transport inhibitor. This suggested that SlBEL11 prevents premature fruit abscission by modulating auxin efflux from fruits, which is crucial for the formation of an auxin response gradient. Indeed, quercetin treatment suppressed premature fruit drop in SlBEL11-RNAi plants. DNA affinity purification sequencing (DAP-seq) analysis indicated that SlBEL11 induced expression of the transcription factor gene SlMYB111 by directly binding to its promoter. Chromatin immunoprecipitation-quantitative polymerase chain reaction and electrophoretic mobility shift assay showed that S. lycopersicum MYELOBLASTOSIS VIRAL ONCOGENE HOMOLOG111 (SlMYB111) induces the expression of the core flavonoid biosynthesis genes SlCHS1, SlCHI, SlF3H, and SlFLS by directly binding to their promoters. Our findings suggest that the SlBEL11-SlMYB111 module modulates flavonoid biosynthesis to fine-tune auxin efflux from fruits and thus maintain an auxin response gradient in the pedicel, thereby preventing premature fruit drop.

Galactinol Regulates JA Biosynthesis to Enhance Tomato Cold Tolerance.

Low temperatures can inhibit plant growth and development and reduce fruit yield. This study demonstrated that the expression of AnGolS1 from Ammopiptanthus nanus (A. nanus) encoding a galactinol synthase enhanced tomato cold tolerance. In AnGolS1-overexpressing plants, the jasmonic acid (JA) biosynthesis substrates 13-hydroperoxylinolenicacid and 12,13-epoxylinolenicacid were significantly accumulated, and the expression levels of the ethylene response factor (SlERF4-7) and serine protease inhibitor (SlSPI5) were increased. We speculated that there may be correlations among galactinol, ethylene signaling, the protease inhibitor, protease, and JA levels. The expression levels of SlERF4-7 and SlSPI5 as well as the JA content were significantly increased under exogenous galactinol treatment. Additionally, the expression of SlSPI5 was reduced in SlERF4-7-silenced plants, and SlERF4-7 was confirmed to bind to the dehydration-responsive element (DRE) of the SlSPI5 promoter. These results suggest that SlSPI5 is a target gene of the SlERF4-7 transcription factor. In addition, SlSPI5 interacted with cysteine protease (SlCPase), while SlCPase interacted with lipoxygenase (SlLOX5) and allene oxide synthase (SlAOS2). When SlCPase was silenced, JA levels increased and plant cold tolerance was enhanced. Therefore, galactinol regulates JA biosynthesis to enhance tomato cold tolerance through the SlERF4-7-SlSPI5-SlCPase-SlLOX5/SlAOS2 model. Overall, our study provides new perspectives on the role of galactinol in the JA regulatory network in plant adaptation to low-temperature stress.

Light quality regulates plant biomass and fruit quality through a photoreceptor-dependent HY5-LHC/CYCB module in tomato.

Increasing photosynthesis and light capture offers possibilities for improving crop yield and provides a sustainable way to meet the increasing global demand for food. However, the poor light transmittance of transparent plastic films and shade avoidance at high planting density seriously reduce photosynthesis and alter fruit quality in vegetable crops, and therefore it is important to investigate the mechanisms of light signaling regulation of photosynthesis and metabolism in tomato (Solanum lycopersicum). Here, a combination of red, blue, and white (R1W1B0.5) light promoted the accumulation of chlorophyll, carotenoid, and anthocyanin, and enhanced photosynthesis and electron transport rates by increasing the density of active reaction centers and the expression of the genes LIGHT-HARVESTING COMPLEX B (SlLHCB) and A (SlLHCA), resulting in increased plant biomass. In addition, R1W1B0.5 light induced carotenoid accumulation and fruit ripening by decreasing the expression of LYCOPENE ß-CYCLASE (SlCYCB). Disruption of SlCYCB largely induced fruit lycopene accumulation, and reduced chlorophyll content and photosynthesis in leaves under red, blue, and white light. Molecular studies showed that ELONGATED HYPOCOTYL 5 (SlHY5) directly activated SlCYCB, SlLHCB, and SlLHCA expression to enhance chlorophyll accumulation and photosynthesis. Furthermore, R1W1B0.5 light-induced chlorophyll accumulation, photosynthesis, and SlHY5 expression were largely decreased in the slphyb1cry1 mutant. Collectively, R1W1B0.5 light noticeably promoted photosynthesis, biomass, and fruit quality through the photoreceptor (SlPHYB1 and SlCRY1)-SlHY5-SlLHCA/B/SlCYCB module in tomato. Thus, the manipulation of light environments in protected agriculture is a crucial tool to regulate the two vital agronomic traits related to crop production efficiency and fruit nutritional quality in tomato.

Synthesis and structural characteristics analysis of melanin pigments induced by blue light in Morchella sextelata.

Morchella sextelata, a highly sought-after edible mushroom worldwide, is evaluated based on its cap color as an essential commercial property indicator. In the present study, the effects of blue light on cap pigmentation in M. sextelata, as well as the synthesis and structural characteristics of melanin pigments within the cap were examined. The results showed that an increase in the proportion of blue light within the lighting environment promoted melanin synthesis and melanization of the cap. Transmission and scanning electron microscopy revealed the localization of melanin within the mycelium and its ultrastructural characteristics. The UV-visible analysis demonstrated that melanin exhibited a maximum absorption peak at 220 nm and possessed high alkaline solubility as well as acid precipitability. The structural characteristics of melanin were analyzed using FTIR, NMR, HPLC, and elemental analysis, which confirmed the presence of eumelanin, pheomelanin, and allomelanin in both brown and black caps. Furthermore, blue light can stimulate the synthesis of both eumelanin and pheomelanin. The obtained results can serve as the foundation for comprehending the mechanism by which light regulates color formation in mushrooms.

A molecular framework for lc controlled locule development of the floral meristem in tomato.

Malformed tomato fruit with multiple locules is a common physiological disorder that significantly affects the quality of tomatoes. Research has shown that the occurrence of malformed fruit in tomatoes is closely linked to the number of locules, and two key QTLs, lc and fas, are involved in controlling this trait. It has been observed that lc has a relatively weaker effect on increasing locule number, which is associated with two SNPs in the CArG repressor element downstream of the SlWUS. However, the precise molecular mechanism underlying lc is not yet fully understood. In this study, we investigated the role of lc in tomato locule development. We found that the number of floral organs and fruit locules significantly increased in tomato lc knockout mutants. Additionally, these mutants showed higher expression levels of the SlWUS during carpel formation. Through cDNA library construction and yeast one-hybrid screening, we identified the MADS-box transcription factor SlSEP3, which was found to bind to lc. Furthermore, we observed an increase in floral organs and fruit locules similar to the lc CR plant on SlSEP3 silencing plants. However, it should be noted that the lc site is located after the 3' untranslated region (UTR) of SlWUS in the tomato genome. As a result, SlSEP3 may not be able to exert regulatory functions on the promoter of the gene like other transcription factors. In the yeast two-hybrid assay, we found that several histone deacetylases (SlHDA1, SlHDA3, SlHDA4, SlHDA5, SlHDA6, SlHDA7, and SlHDA8) can interact with SlSEP3. This indicated that SlSEP3 can recruit these proteins to repress nucleosome relaxation, thereby inhibiting SlWUS transcription and affecting the number of locules in tomato fruit. Therefore, our findings reveal a new mechanism for lc playing a significant role in the genetic pathway regulating tomato locule development.

Effects of Low Temperature on Pedicel Abscission and Auxin Synthesis Key Genes of Tomato.

Cold stress usually causes the abscission of floral organs and a decline in fruit setting rate, seriously reducing tomato yield. Auxin is one of the key hormones that affects the abscission of plant floral organs; the YUCCA (YUC) family is a key gene in the auxin biosynthesis pathway, but there are few research reports on the abscission of tomato flower organs. This experiment found that, under low temperature stress, the expression of auxin synthesis genes increased in stamens but decreased in pistils. Low temperature treatment decreased pollen vigor and pollen germination rate. Low night temperature reduced the tomato fruit setting rate and led to parthenocarpy, and the treatment effect was most obvious in the early stage of tomato pollen development. The abscission rate of tomato pTRV-Slfzy3 and pTRV-Slfzy5 silenced plants was higher than that of the control, which is the key auxin synthesis gene affecting the abscission rate. The expression of Solyc07g043580 was down-regulated after low night temperature treatment. Solyc07g043580 encodes the bHLH-type transcription factor SlPIF4. It has been reported that PIF4 regulates the expression of auxin synthesis and synthesis genes, and is a key protein in the interaction between low temperature stress and light in regulating plant development.

Silencing SlPP2C expression delayed plant senescence and fruit ripening in tomato.

Type 2C protein phosphatases (PP2Cs) play key roles in regulating plant senescence and ripening. Here, we discovered a subfamily F PP2C, SlPP2C, associated with leaf senescence through transcriptome analysis. The gene expression, protein accumulation, and promoter activity of SlPP2C all gradually increased along with the progression of leaf and flower senescence and fruit ripening in tomato. Also, the expression of SlPP2C was highly up-regulated by the senescent-inducible hormone treatments, showing more sensitivity to ethylene (ETH) and abscisic acid (ABA). Meanwhile, SlPP2C RNA interference (RNAi) tomato transgenic lines showed obvious delayed senescence and ripening phenotypes of leaves, flowers, and fruits. SlPP2C RNAi lines delayed leaf senescence with higher chlorophyll fluorescence and content, and lower expressions of senescence marker genes (SlSGR1 and SlSAG12) compared to WT. SlPP2C RNAi lines clearly delayed flower senescence time; it was at least twice longer than WT. SlPP2C RNAi lines delayed fruit ripening, exhibiting higher firmness and lower polygalacturonase activity compared to WT. In addition, we proved that SlPP2C is unable to interact with any of the ABA receptors (SlPYLs). Together, the results demonstrate that SlPP2C is a senescence-related and ripening-related gene.

Integrated enzymes activity and transcriptome reveal the effect of exogenous melatonin on the strain degeneration of Cordyceps militaris.

As a valuable medicinal and edible fungus, Cordyceps militaris has been industrialized with broad development prospects. It contains a lot of bioactive compounds that are beneficial to our health. However, during artificial cultivation, strain degeneration is a challenge that inhibits the industrialization utility of C. militaris. Exogenous melatonin (MT) can scavenge for reactive oxygen species (ROS) in fungus and can alleviate strain degeneration. To establish the significance and molecular mechanisms of MT on strain degeneration, we investigated the third-generation strain (W5-3) of C. militaris via morphological, biochemical, and transcriptomic approaches under MT treatment. Morphological analyses revealed that colony angulation of C. militaris was significantly weakened, and the aerial hypha was reduced by 60 µmol L-1 MT treatment. Biochemical analyses showed low levels of ROS and malondialdehyde (MDA), as well as increasing endogenous MT levels as exogenous MT increased. RNA-Seq revealed that compared with the control, several antioxidant enzyme-related genes were up-regulated under 60 µmol L-1 MT treatment. Among them, glutathione s-transferase genes were up-regulated by a factor of 11.04. In addition, genes that are potentially involved in cordycepin, adenosine and active compound biosynthesis for the growth and development of mycelium were up-regulated. Collectively, these findings provide the basis for further elucidation of the molecular mechanisms involved in C. militaris strain degeneration.

The association between adverse ergonomic factors and work-related musculoskeletal symptoms among medical staff in China: a cross-sectional study.

We investigated the prevalence of work-related musculoskeletal symptoms (WMSs) among medical staff and evaluated the associations of different levels of adverse ergonomic factors with WMSs. A total of 6099 Chinese medical staff were asked to complete a self-reported questionnaire to assess the prevalence and risk factors of WMSs from June 2018 to December 2020. A prevalence rate of 57.5% was observed for WMSs among overall medical staffs, which mainly affected the neck (41.7%) and shoulder (33.5%). 'Keeping sitting for long hours very frequently' (OR = 1.26, 95% CI: 1.04, 1.53) was positively associated with WMSs in doctors, while 'keeping sitting for long hours occasionally' (OR = 0.91, 95% CI: 0.85, 0.97) was identified as a protective factor of WMSs in nurses. The associations of adverse ergonomic factors, organisational factors, and environmental factors with WMSs were different among medical staff in different positions.Practitioner summary: We conducted a multi-city study concerning the risk factors of WMSs by carrying out a face-to-face one-to-multiple questionnaire survey among medical staff in China. As a risk factor of WMSs in medical staff, adverse ergonomic factors should be paid more attention by the standard setting department and policy makers.Abbreviations: WMSDs: work-related musculoskeletal disorders; WMSs: work-related musculoskeletal symptoms; MSDs: musculoskeletal disorders; NMQ: Nordic Musculoskeletal Questionnaires; DMQ: Dutch Musculoskeletal Questionnaires; NIOSH: National Institute for Occupational Safety and Health; ORs: odds ratios.

MicroRNA162 regulates stomatal conductance in response to low night temperature stress via abscisic acid signaling pathway in tomato.

MicroRNAs (miRNAs) mediate the degradation of target mRNA and inhibit mRNA translation to regulate gene expression at the transcriptional and post-transcriptional levels in response to environmental stress in plants. We characterized the post-transcriptional mechanism by deep sequencing small RNA (sRNA) to examine how miRNAs were involved in low night temperature (LNT) stress in tomato and whether the molecular mechanism depended on the abscisic acid (ABA) signaling pathway. We annotated conserved miRNAs and novel miRNAs with four sRNA libraries composed of wild-type (WT) tomato plants and ABA-deficient mutant (sit) plants under normal growth and LNT stress conditions. Reverse genetics analysis suggested that miR162 participated in LNT resistance and the ABA-dependent signaling pathway in tomato. miR162-overexpressing (pRI-miR162) and miR162-silenced (pRNAi-miR162) transgenic tomato plants were generated to evaluate miR162 functions in response to LNT stress. miR162 deficiency exhibited high photosynthetic capacity and regulated stomatal opening, suggesting negative regulation of miR162 in the ABA-dependent signaling pathway in response to LNT stress. As feedback regulation, miR162 positively regulated ABA to maintain homeostasis of tomato under diverse abiotic stresses. The mRNA of DICER-LIKE1 (DCL1) was targeted by miR162, and miR162 inhibited DCL1 cleavage in LNT response, including the regulation of miRNA160/164/171a and their targets. The DCL1-deficient mutants (dcl1) with CRISPR/Cas9 prevented stomatal opening to influence photosynthesis in the ABA signaling pathway under LNT stress. Finally, we established the regulatory mechanism of ABA-miR162-DCL1, which systematically mediated cold tolerance in tomato. This study suggests that post-transcriptional modulators acted as systemic signal responders via the stress hormone signaling pathway, and the model at the post-transcriptional level presents a new direction for research in plant abiotic stress resistance.

Exogenous melatonin enhances tomato heat resistance by regulating photosynthetic electron flux and maintaining ROS homeostasis.

Heat stress reduces plant growth and reproduction and increases agricultural risks. As a natural compound, melatonin modulates broad aspects of the responses of plants to various biotic and abiotic stresses. However, regulation of the photosynthetic electron transfer, reactive oxygen species (ROS) homeostasis and the redox state of redox-sensitive proteins in the tolerance to heat stress induced by melatonin remain largely unknown. The oxygen evolution complex activity on the electron-donating side of photosystem II (PSII) is inhibited, and the electron transfer process from QA to QB on the electron-accepting side of PSII is inhibited. In this case, heat stress decreased the chlorophyll content, carbon assimilation rate, PSII activity, and the proportion of light absorbed by tomato seedlings during electron transfer. The ROS burst led to the breakdown of the PSII core protein. However, exogenous melatonin increased the net photosynthetic rate by 11.3% compared with heat stress, substantially reducing the restriction of photosynthetic systems induced by heat stress. Additionally, melatonin reduces the oxidative damage to PSII by balancing electron transfer on the donor, reactive center, and acceptor sides. Melatonin was used under heat stress to increase the activity of the antioxidant enzyme and preserve ROS equilibrium. In addition, redox proteomics also showed that melatonin controls the redox levels of proteins involved in photosynthesis, and stress and defense processes, which enhances the expression of oxidative genes. In conclusion, melatonin via controlling the photosynthetic electron transport and antioxidant, melatonin increased tomato heat stress tolerance and aided plant growth.

Tetratricopeptide repeat protein SlREC2 positively regulates cold tolerance in tomato.

Cold stress is a key environmental constraint that dramatically affects the growth, productivity, and quality of tomato (Solanum lycopersicum); however, the underlying molecular mechanisms of cold tolerance remain poorly understood. In this study, we identified REDUCED CHLOROPLAST COVERAGE 2 (SlREC2) encoding a tetratricopeptide repeat protein that positively regulates tomato cold tolerance. Disruption of SlREC2 largely reduced abscisic acid (ABA) levels, photoprotection, and the expression of C-REPEAT BINDING FACTOR (CBF)-pathway genes in tomato plants under cold stress. ABA deficiency in the notabilis (not) mutant, which carries a mutation in 9-CIS-EPOXYCAROTENOID DIOXYGENASE 1 (SlNCED1), strongly inhibited the cold tolerance of SlREC2-silenced plants and empty vector control plants and resulted in a similar phenotype. In addition, foliar application of ABA rescued the cold tolerance of SlREC2-silenced plants, which confirms that SlNCED1-mediated ABA accumulation is required for SlREC2-regulated cold tolerance. Strikingly, SlREC2 physically interacted with ß-RING CAROTENE HYDROXYLASE 1b (SlBCH1b), a key regulatory enzyme in the xanthophyll cycle. Disruption of SlBCH1b severely impaired photoprotection, ABA accumulation, and CBF-pathway gene expression in tomato plants under cold stress. Taken together, this study reveals that SlREC2 interacts with SlBCH1b to enhance cold tolerance in tomato via integration of SlNCED1-mediated ABA accumulation, photoprotection, and the CBF-pathway, thus providing further genetic knowledge for breeding cold-resistant tomato varieties.

Creation of a Plant Metabolite Spectral Library for Untargeted and Targeted Metabolomics.

Large-scale high throughput metabolomic technologies are indispensable components of systems biology in terms of discovering and defining the metabolite parts of the system. However, the lack of a plant metabolite spectral library limits the metabolite identification of plant metabolomic studies. Here, we have created a plant metabolite spectral library using 544 authentic standards, which increased the efficiency of identification for untargeted metabolomic studies. The process of creating the spectral library was described, and the mzVault library was deposited in the public repository for free download. Furthermore, based on the spectral library, we describe a process of creating a pseudo-targeted method, which was applied to a proof-of-concept study of Arabidopsis leaf extracts. As authentic standards become available, more metabolite spectra can be easily incorporated into the spectral library to improve the mzVault package.

Fine mapping and cloning of a novel BrSCC1 gene for seed coat color in Brassica rapa L.

KEY MESSAGE: A novel BrSCC1 gene for seed coat color was fine mapped within a 41.1-kb interval on chromosome A03 in Brassica rapa and functionally validated by ectopic expression analysis. Yellow seed is a valuable breeding trait that can be potentiality applied for improving seed quality and oil productivity in oilseed Brassica crops. However, only few genes for yellow seed have been identified in B. rapa. We previously identified a minor quantitative trait locus (QTL), qSC3.1, for seed coat color on chromosome A03 in B. rapa. In order to isolate the seed coat color gene, a brown-seeded chromosome segment substitution line, CSSL-38, harboring the qSC3.1, was selected and crossed with the yellow-seeded recurrent parent, a rapid cycling inbred line of B. rapa (RcBr), to construct the secondary F2 population. Metabolite identification suggested that seed coat coloration in CSSL-38 was independent of proanthocyanidins (PAs) accumulation. Genetic analysis revealed that yellow seed was controlled by a single recessive gene, Seed Coat Color 1 (BrSCC1). Utilizing bulked segregant analysis (BSA)-seq and secondary F2 and F2:3 recombinants analysis, BrSCC1 was fine mapped within a 41.1-kb interval. By integrating gene expression profiling, genome sequence comparison, metabolite analysis, and functional validation through ectopic expression in Arabidopsis, the BraA03g040800.3C gene was confirmed to be BrSCC1, which positively correlated with the seed coat coloration. Our study provides a novel gene resource for the genetic improvement of yellow seeds in oilseed B. rapa.