Transcriptomics and metabolomics analyses provide insights into postharvest ripening and senescence of tomato fruit under low temperature

Tomato is one of the most important vegetable crops in the world and is a model plant used to study the ripening of climacteric fleshy fruit.During the ripening process of tomato fruit,flavor and aroma metabolites,color,texture and plant hormones undergo significant changes.However,low temperatures delayed the ripening process of tomato fruit,inhibiting flavor compounds and ethylene production.Metabolomics and transcriptomics analyses of tomato fruit stored under low temperature(LT,5°C)and room temperature(RT,25°C)were carried out to investigate the effects of storage temperature on the physiological changes in tomato fruit after harvest.The results of transcriptomics changes revealed that the differentially expressed genes(DEGs)involved in tomato fruit ripening,including several kinds of transcription factors(TFs)(TCP,WRKY,MYB and bZIP),enzymes involved in cell wall metabolism[beta-galactosidase(β-GAL),pectinesterase(PE)and pectate lyase(PL),cellulose and cellulose synthase(CESA)],enzymes associated with fruit flavor and aroma[acetyltransferase(AT),malic enzyme(ME),lipoxygenase(LOX),aldehyde dehydrogenase(ALDH),alcohol dehydrogenase(ADH)and hexokinase(HK)],genes associated with heat stress protein 70 and genes involved in the production of plant hormones such as Ethylene responsive factor 1(ERF1),Auxin/indoleacetic acids protein(AUX/IAA),gibberellin regulated protein.Based on the above results,we constructed a regulatory network model of the effects of different temperatures during the fruit ripening process.According to the analysis of the metabolomics results,it was found that the contents of many metabolites in tomato fruit were greatly affected by storage temperature,including,organic acids(L-tartaric acid,a-hydroxyisobutyric acid and 4-acetamidobutyric acid),sugars(melezitose,beta-Dlactose,D-sedoheptulose 7-phosphate,2-deoxyribose 1-phosphate and raffinose)and phenols(coniferin,curcumin and feruloylputrescine).This study revealed the effects of storage temperature on postharvest tomato fruit and provided a basis for further understanding of the molecular biology and biochemistry of fruit ripening.

Procyanidin A_1 and its digestive products alleviate acrylamide-induced IPEC-J2 cell damage through regulating Keap1/Nrf2 pathway

Our previous study has revealed that procyanidin A_(1)(A_(1))and its simulated digestive product(D-A,)can alleviate acrylamide(ACR)-induced intestine cell damage.However,the underlying mechanism remains unknown.In this study,we elucidated the molecular mechanism for and D-A_(1) to alleviate ACR-stimulated IPEC-J2 cell damage.ACR slightly activated nuclear factor erythroid 2-related factor 2(Nrf2)signaling and its target genes,but this activation could not reduce intestine cell damage.A_(1) and D-A_(1) could alleviate ACR-induced cell damage,but the effect was abrogated in cells transiently transfected with Nrf2 small interfering RNA(siRNA).Further investigation confirmed that A_(1) and D-A_(1) interacted with Ketch-like ECH-associated protein 1(Keapl),which boosted the stabilization of Nrf2,subsequently promoted the translocation of Nrf2 into the nucleus,and further increased the expression of antioxidant proteins,thereby inhibiting glutathione(GSH)consumption,maintaining redox balance and eventually alleviating ACR-induced cell damage.Importantly,there was no difference between A_(1) and D-A_(1) treated groups,indicating that A_(1) can tolerate gastrointestinal digestion and may be a potential compound to limit the toxicity of ACR.

Microbial phenolic metabolites 3-(3',4'-dihydroxyphenyl)propanoic acid and 3',4'-dihydroxyphenylacetic acid prevent obesity in mice fed high-fat diet

Obesity is associated with numerous metabolic disorders,and dietary polyphenols have been confirmed to have beneficial effects on the metabolism in obesity.However,the effect of 3-(3’,4’-dihydroxyphenyl)propanoic acid(DHPA)and 3’,4’-dihydroxyphenylacetic acid(DHAA),two main metabolites of dietary polyphenols,on obesity remains poorly understood.In this study,DHPA and DHAA were found to alleviate obesity,as well as regulate insulin resistance,lipid metabolism,and oxidative stress response in high-fat diet(HFD)mice.Surprisingly,the 16S rRNA sequencing and UHPLC-Q-TOF/MS demonstrated that DHPA and DHAA only slightly disturbed the intestinal microbiome,but significantly altered the urine metabolome of HFD mice mainly by regulating pentose and glucuronate interconversion,tyrosine metabolism,pentose phosphate and tricarboxylic acid(TCA)cycle as indicated by metabolic pathway analysis based on Kyoto Encyclopedia of Genes and Genomes(KEGG)database.Correlation analysis revealed that the differential metabolites are strongly associated with body weight,blood glucose,insulin level,and superoxide dismutase(SOD)enzyme activity.Our results revealed that DHPA and DHAA exert their anti-obesity effect by regulating important metabolites in the glucose,lipid and tyrosine metabolism pathways.

Soil application of Trichoderma asperellum GDFS1009 granules promotes growth and resistance to Fusarium graminearum in maize

Of diseases affecting maize(Zea mays), Fusarium graminearum is one of the most common pathogenic fungi that cause stalk rot. In the present study, the Trichoderma asperellum GDFS1009 strain was shown to be an effective biocontrol agent against stalk rot. In a confrontation culture test, Trichoderma strain displayed an approximately 60% inhibition rate on the mycelial growth of F. graminearum. In pot trials, the application of 2 g/pot of T. asperellum GDFS1009 granules had the best control effect on stalk rot at the seedling stage(up to 53.7%), while the average plant height and fresh weight were also significantly improved. Additionally when fertilizer was added at 8 g/pot, the application of 3 g/pot of Trichoderma granules had the best control effect on maize stalk rot(40.95%). In field trials, when inoculating F. graminearum alone, the disease index for inoculating was 62.45, but only 31.43 after treatment with T. asperellum GDFS1009 granules, suggesting a control efficiency of 49.67%. Furthermore, in a naturally F. graminearum-infected field, Trichoderma granules, when applied for 3 consecutive years, showed significant control of stalk rot and increased yields.

Combined application of Trichoderma harzianum SH2303 and difenoconazole-propiconazolein controlling Southern corn leaf blight disease caused by Cochliobolus heterostrophus in maize

Southern corn leaf blight(SCLB)disease caused by Cochliobolus heterostrophus is one of the major threats to corn production worldwide.The synergistic application of low toxic chemical fungicide and biocontrol agents could improve biocontrol stability and efficiency against plant diseases,which ultimately reduce use of chemical fungicide.Trichoderma spp.,well-known biocontrol fungi have been used to control some foliar diseases.However,few works have been reported on synergistic application of chemical fungicide and Trichoderma against foliar diseases.This study was aimed to investigate the control effect on the synergistic application of Trichoderma harzianum SH2303 and difenoconazole-propiconazole(DP)against SCLB.Results showed that the synergistic application of DP and SH2303 reduced the leaf spot area compared to the control.The efficacy of synergistic application of DP+SH2303 against SCLB could last for 15–20 d in pot trial under the greenhouse condition.Under the natural field condition,maize treated with DP+DP and DP+SH2303 showed 60%control,which was higher than that of SH2303+DP(45%)and SH2303+SH2303(35%).All these treatments induced the synthesis of defense-related enzymes(phenylalanine ammonia lyase(PAL),catalase(CAT),and superoxide dismutase(SOD))and the defence-related gene expression of SA pathway(PR1).Taken together the in-vitro leaf test and field trial,the control of SCLB by synergistic application of DP+SH2303 was similar to that of DP+DP.Among synergistic application,the sequential application of DP+SH2303 showed better control than the sequential application of SH2303+DP.It was concluded that the synergistic application of chemical fungicide(DP)and biocontrol agent(T.harzianum SH2303)could be used to reduce the chemical fungicide and to reduce the SCLB diseases in maize,which provided alternative approach to realize an eco-friendly controlling of the foliar disease.

Screening of antagonistic Trichoderma strains and their application for controlling stalk rot in maize

Maize is one of the major crops in China, but maize stalk rot occurs nationwide and has become one of the major challenges in maize production in China. In order to find an environment-friendly and feasible technology to control this disease, a Trichoderma-based biocontrol agent was selected. Forty-eight strains with various inhibition activities to Fusarium graminearum, and Fusarium verticillioides were tested. A group of Trichoderma strains(DLY31, SG3403, DLY1303 and GDFS1009) were found to provide an inhibition rate to pathogen growth in vitro of over 70%. These strains also prevented pathogen infection over 65% and promoted the maize seedling growth for the main root in vivo by over 50%. Due to its advantage in antifungal activity against pathogens and promotion activity to maize, Trichoderma asperellum GDSF1009 was selected as the most promising strain of the biocontrol agent in the Trichoderma spectrum. Pot experiments showed that the Trichoderma agent at 2–3 g/pot could achieve the best control of seedling stalk rot and promotion of maize seedling growth. In the field experiments, 8–10 g/hole was able to achieve over 65% control to stalk rot, and yield increased by 2–11%. In the case of natural morbidity, the control efficiency ranged from 27.23 to 48.84%, and the rate of yield increase reached 11.70%, with a dosage of Trichoderma granules at 75 kg ha^-1. Based on these results, we concluded that the Trichoderma agent is a promising biocontrol approach to stalk rot in maize.

Effect of different levels of nitrogen deficiency on switchgrass seedling growth

Switchgrass(Panicum virgatum L.) is a warm-season rhizomatous perennial grass that can tolerate diverse abiotic stresses while yielding relatively high biomass, and is considered a leading biofuel feedstock for marginal lands. Nitrogen(N) is crucial for the growth and development of switchgrass, and its tolerance to low N supply and high N use efficiency are very important for its production under poor conditions. The large-scale planting of switchgrass on marginal lands could be an effective approach to solving the problem of feedstock supply for biomass energy. This study used a hydroponic experiment to evaluate the effect of N deficiency on switchgrass seedlings. Three N treatments(0, 0.15, and 1.50 mmol L-1Hoagland's solution)and six cultivars were used, three of each ecotype(upland and lowland). The results showed that biomass, leaf area, root surface area, net photosynthesis, and total chlorophyll content significantly decreased under low N treatments compared with those in full strength Hoagland's nutrient solution. However, once established, all plants survived extreme N stress(0 mmol L-1) and, to some extent, were productive. Cultivar Kanlow performed best of the six cultivars under stress. Significant interactions between stress treatment and cultivars showed that breeding for cultivars with high yield and superior performance under N deficiency is warranted. The lowland outperformed the upland ecotypes under stress, suggesting that lowland cultivars may survive and be productive under a wider range of stress conditions.However, given the better adaptability of lowland ecotypes to hydroponic cultivation, further study is needed.

CPTA treatment reveals potential transcription factors associated with carotenoid metabolism in flowers of Osmanthus fragrans

Osmanthus fragrans is one of the top ten traditional flowers in China.It is divided into three different groups according to its color.α-Carotene and β-carotene are the main determinants to distinguish the color differences between three groups.However,the dominant genes and transcription factors involved in carotenoid metabolism remain unclear.CPTA treatment(0.7mmol·L−1)remarkably promoted lycopene,α-carotene and β-carotene contents in flowers.Transcriptome sequencing analysis revealed that CPTA treatment could trigger chain reactions in carotenoid metabolism pathway genes.Four up-regulated and 10 down-regulated transcription factors which have close association with carotenoid variation were significantly induced by CPTA treatment.The up-regulated TFs such as MYB43,MYB123,HSF,were further subjected to transcript expression determination in different cultivars with drastic colors.Among them,transcript expression of four up-regulated TFs coincided with the carotenoid accumulation in different cultivars.We selected up-regulated OfMYB43 to verify its function,which is related to stress tolerance and transcriptional regulation.Transient overexpression of OfMYB43 in O.fragrans flowers showed that it could remarkably promote the expression of PDS,ZISO,LCYE and CCD4,leading to increased accumulation of β-branch carotenoids.OfMYB43 was a potential positive regulator of carotenoid biosynthesis in O.fragrans flowers.This study provides insight into the molecular mechanism of carotenoid metabolism in O.fragrans.

Comparative transcriptome analysis of different heat stress responses between self-root grafting line and heterogeneous grafting line in rose

Rose is sensitive to high temperature which will make the rose go into a semi-dormancy state.Grafting is an excellent way to enhance rose heat tolerance.Here,heat-tolerant Rosa multiflora‘Huanong Wuci 1'(W)and heat-sensitive Rosa chinensis‘Old Blush’(X)were selected as experimental materials.The RNA-seq technique was used to investigate the transcriptomes of self-root grafting line(XX0),heterogeneous grafting line(XW0),self-root grafting line under 6 h heat stress(XX6),and heterogeneous grafting line under 6 h heat stress(XW6).Under high temperature stress,multiple signaling pathways were activated,moreover,a large number of transcription factors and functional genes were induced,especially the HSFs and HSPs with remarkably upregulated expression levels.The GO analysis showed that the differences in the expressions of the genes related to fatty acids and carbohydrates were observed between self-root grafting line and heterogeneous grafting line.In addition,14 P450s were differentially expressed,and one lectin gene was up-regulated in XW0 vs XW6,but down-regulated in XX0 vs XX6.Considering physiological and biochemical traits such as relative electrolyte leakage,SOD activity,proline,and total soluble sugars,DEGs involved in these processes may be key factors to resist high temperature.The present study provides an insight into the complex mechanism underlying grafting in response to heat stress.Our results indicate that grafting is an effective way to improve rose heat resistance.

Inhibitory effect of chitosan on growth of the fungal phytopathogen,Sclerotinia sclerotiorum,and sclerotinia rot of carrot

The antifungal activity of chitosan on a common fungal phytopathogen, Sclerotinia sclerotiorum, and the control effect on sclerotinia rot of carrot were investigated. Mycelial growth and fungal biomass were strongly inhibited by chitosan. Using propidium iodide stain combined with fluorescent microscopy, the plasma membrane of chitosan-treated S. sclerotiorum mycelia was observed to be markedly damaged. Concomitantly, protein leakage and lipid peroxidation was also found to be significantly higher in chitosan-treated mycelia compared to the control. Chitosan provided an effective control of sclerotinia rot of carrot, with induction of activity of defense-related enzymes including polyphenoloxidase and peroxidase. These data suggest that the effects of chitosan on sclerotinia rot of carrot may be associated with the direct damage to the plasma membrane and lipid peroxidation of S. sclerotiorum, and the elicitation of defense response in carrot.

Sod gene of Curvularia lunata is associated with the virulence in maize leaf

Curvularia leaf spot, caused mainly by Curvularia lunata, is a widespread plant disease in China. In the recent years, di- rectional host selection by the pathogen, which likely results in the virulence differentiation in pathogens, is widely reported. Among the hallmarks potentially associated to pathogen variation in virulence, superoxide dismutase gene Sod has been found to be closely related to the enhancement of virulence. In the present study, the full-length of Sod was obtained via Blastn alignment against GenBank and the whole genome of C. lunata. In order to understand the role of Sod in the vir- ulence variation in C. lunata, targeted gene disruption was performed to construct Sod mutants. The cell wall degrading enzyme （CWDE） activities and toxin production of ASod were not distinctly different from wild-type strain CX-3 and its complon. However, at an early stage of infection, 3Sod virulence appeared to be lower than CX-3 and the complon, while at a later stage, its virulence gradually returned to the level of CX-3 and the complon. Furthermore, the melanin production of ASod was significantly reduced compared to CX-3 and the complon, suggesting that Sod gene influences the virulence by regulating melanin production at an early stage of infection but is not essential for pathogenicity. However, the disruption of Sod did not significantly affect the transcriptional expression of the melanin biosynthesis-associated genes, bml and scd. Therefore, we infer that Sod in C. lunata are involved, to some extent, with the virulence in maize leaf, but still needs further studies to have a clear understanding of its mechanism.

6-Benzylaminopurine treatment maintains the quality of Chinese chive(Allium tuberosum Rottler ex Spreng.) by enhancing antioxidant enzyme activity

Chinese chive usually develops an off-flavor after a short storage time. To explore effective ways to maintain the postharvest quality of Chinese chive, the effect of exogenous application of 6-benzylaminopurine（6-BA） on postharvest quality and antioxidant activity of chive was evaluated, and the mechanism of the physiological responses of chive to 6-BA treatment was explored. Chives were sprayed for 10 min with 100, 300, or 500 mg L–1 6-BA or with alkaline solution as the control, then stored at（2±1）°C with a relative humidity（RH） of 80–85%. We found that 300 mg L–1 6-BA significantly delayed yellowing and chlorophyll degradation, maintained the total phenolic and flavonoid content, and improved the activities of antioxidant enzymes, including superoxide dismutase（SOD）, catalase（CAT） and peroxidase（POD）. In conclusion, we identified exogenous application of 6-BA as an effective method for maintaining postharvest quality of Chinese chive. In addition, our finding that the activities of antioxidant enzymes increase in response to exogenous 6-BA provides new insights into the mechanism of cytokinin-based postharvest fresh-keeping.

Comparative Analysis of Gene Expression in Two Muskmelon Cultivars(Cucumis melo L.) Under Salt Stress

Salinity is one of the most important abiotic stresses that adversely affects crop growth and productivity. A subtractive suppression hybridization （SSH） library were constructed from the roots of salt-sensitive Yulu cultivar melon seedlings under salt stress; 557 high-quality expressed sequence tags （ESTs） were randomly sequenced, with an average size of 428 bp, which assembled into 68 contigs and 315 singletons. Compared with our previous SSH library generated from the salt-tolerant Bingxuecui cultivar, the proportion of transcripts involved in metabolism, protein fate, cellular communication/signal transduction mechanisms, and cell rescue/defense were 4, 1.46, 0.94, and 0.4% higher, respectively, in the salt-tolerant cultivar than the in salt-sensitive cultivar. Quantitative real-time PCR analysis of eleven transcripts revealed temporal variations in their expression in the two cultivars under salt stress. One NAC gene （JZ477011） was heterologously expressed in yeast for functional characterization, and enhanced the sensitivity of yeast cells to high-salinity to salt stress and inhibited their growth. Information regards to their functions would aid in the understanding of response mechanisms to saline stress and in the development of molecular markers for selecting salt-tolerant melon cultivars.

Genome-wide detection for runs of homozygosity analysis in three pig breeds from Chinese Taihu Basin and Landrace pigs by SLAF-seq data

Erhualian(E),Meishan(MS)and Mi(MI)pigs are excellent indigenous pig breeds in Chinese Taihu Basin,which have made great contributions to the genetic improvement of commercial pigs.Investigation of the genetic structure and inbreeding level of the 3 pig breeds is of great significance for the sustainable breeding of commercial pigs.The length and number of runs of homozygosity(ROH)as well as the frequency of genomes covered by ROH can be used as indicators to evaluate the level of inbreeding and the origin of the population.In this study,the ROH characteristics of E,MS,MI and Landrace(L)pigs were analyzed by SLAF-seq data,and the inbreeding coefficient based on ROH(F_(ROH))was calculated.In addition,we have identified candidate genes in the genomic regions associated with ROH.A total of10568 ROH were detected in 116 individuals of 4 pig breeds.The analysis showed that there were significant differences in genetic structure between 3 Taihu Basin pig breeds and L,and the genetic structure of E and MI was similar.The results of F_(ROH)showed that the inbreeding level of MS was the highest(0.25±0.07),while E and MI were lower than L.Compared with the other 3 pig populations,MS showed a higher frequency of long ROH(>5 Mb),indicating higher inbreeding in MS in recent generations.A large number of candidate genes related to reproductive traits are located in the genomic regions with a high frequency of ROH,and these genes are expected to be used as candidate genes in marker-assisted selection(MAS)breeding programs.Our findings can provide theoretical support for genetic conservation and genetic improvement of 3 pig breeds in Chinese Taihu Basin.

Regulations of m^(6)A methylation on tomato fruit chilling injury

Tomato fruit are sensitive to chilling injury(CI)during cold storage.Several factors have been discovered to be involved in chilling injury of tomato fruit.Plant hormones play an important regulatory role,however,the relationship between chilling injury and N6-methyladenosine(m^(6)A)methylation of transcripts in plant hormone pathways has not been reported yet.In order to clarify the complex regulatory mechanism of m^(6)A methylation on chilling injury in tomato fruit,Nanopore direct RNA sequencing was employed.A large number of enzymes and transcription factors were found to be involved in the regulation process of fruit chilling injury,which were associated with plant hormone,such as 1-aminocyclopropane 1-carboxylate synthase(ACS),aspartate aminotransferase(AST),auxin response factor(ARF2),ethylene response factor 2(ERF2),gibberellin 20-oxidase-3(GA20ox)and jasmonic acid(JA).By conjoint analysis of the differential expression transcripts related to chilling injury andm^(6)Amethylation differential expression transcripts 41 differential expression transcripts were identified involved in chilling injury including 1-aminocyclopropane-1-carboxylate oxidase(ACO)and pectinesterase(PE)were down-regulated and heat shock cognate 70 kD protein 2(cpHSC70),HSP70-binding protein(HspBP)and salicylic acid-binding protein 2(SABP2)were up-regulated.Our results will provide a deeper understanding for chilling injury regulatory mechanism and post-harvest cold storage of tomato fruit.

Development Status, Problems and Countermeasures of Large- and Intermediate-Scale Biogas Projects in Beijing’s Mountainous Counties

Developing large- and intermediate-scale biogas project is an important gripper ofBeijingrural energy construction and “Green Beijing” construction. The existing projects have made obvious energy and environment benefits, but the overall effects have not been fully exerted. There is still a large gap betweenBeijing’s ecological civilization goal and the operation effect. This paper takes biogas projects ofBeijingseven mountainous counties as examples, the development status, ecological environment construction and existing problems of operating are explained respectively. Finally, some countermeasures and suggestions are proposed for promoting the sustainable development of biogas project inBeijing, such as strengthening technical innovation and setting standards, innovating development patterns and planning reasonable layout, improve the maintenance mechanism and intensify policy support.

The genome and transcriptome analysis of snake gourd provide insights into its evolution and fruit development and ripening

Snake gourd(Trichosanthes anguina L.),which belongs to the Cucurbitaceae family,is a popular ornamental and food crop species with medicinal value and is grown in many parts of the world.Although progress has been made in its genetic improvement,the organization,composition,and evolution of the snake gourd genome remain largely unknown.Here,we report a high-quality genome assembly for snake gourd,comprising 202 contigs,with a total size of 919.8 Mb and an N50 size of 20.1 Mb.These findings indicate that snake gourd has one of the largest genomes of Cucurbitaceae species sequenced to date.The snake gourd genome assembly harbors 22,874 protein-coding genes and 80.0%of the genome consists of repetitive sequences.Phylogenetic analysis reveals that snake gourd is closely related to sponge gourd but diverged from their common ancestor~33–47 million years ago.The genome sequence reported here serves as a valuable resource for snake gourd genetic research and comparative genomic studies in Cucurbitaceae and other plant species.In addition,fruit transcriptome analysis reveals the candidate genes related to quality traits during snake gourd fruit development and provides a basis for future research on snake gourd fruit development and ripening at the transcript level.

Research on the Necessity of Building National-level Grape and Cherry Germplasm Resources Bank in Shandong Province

At present,the grape and cherry industries in Shandong are in the leading position in China and have driven the development of related high-end manufacturing industries such as wine,brandy,preserved fruit processing,fruit juice processing and health products. Therefore,vigorously developing the grape and cherry industries in Shandong Province and carrying out development and innovation are important parts of Shandong Province in responding to the strategy of national new and old kinetic energy conversion. However,currently the germplasm resources preserved in the fruit tree resources banks in China are only 45% of those in the US and 27. 2% of those in the EU. Moreover,the development of fruit trees resources banks in Shandong is relatively backward in China,and there is still no banks related with grape and cherry germplasm resources in Shandong. Therefore,importance can be attached to the agriculture,forestry,and animal husbandry to build germplasm resources banks for grape and cherry industries in Shandong Province. Building the national-level grape and cherry germplasm resources bank in Shandong Province can also promote the utilization of wild and farm germplasm resources in the future; advance the research on the genes related to disease resistance,stress resistance and quality of grapes and cherries; push forward the construction and development of cherry and grape mutants banks. It is conducive to the research on the agronomic traits of grapes and cherries,and can provide the parents resources for planting innovation and improving the quality of grapes and cherries,as well as promote the development and application of molecular markers of grapes and cherries,including the identification of lines and crossbreeding. Thereby,it cannot only promote the industry development,but also achieve the development of cultivation,breeding and basic research in an all-round way and the development of ＂ production,study and research＂ going side by side.

Dual-Roof Solar Greenhouse—A Novel Design for Improving the Heat Preserving Capacity in Northern China

Dual-roof solar greenhouse, a new style of solar greenhouse, was designed in this study intending to reduce heat loss in cold time and improve land use efficiency in Beijing, the Capital city of China. Designing and applying the dual-roof greenhouse in metropolitan area had dual effects of saving energy and enhancing land use efficiency. According to the monitoring study and analysis conducted in winter of 2012, the averaged night temperature of south room was about 12.1°C in December, which was satisfying for growing average leaf vegetables. Total energy saved by dual-roof in whole winter was quantified as 1.1 × 107 MJ&#46yr-1 (winter), potentially about 37.4 t coal was saved in Beijing area during whole winter-growing period. Considering the application of north room, the land use efficiency was improved by 62.5% in dual-roof solar greenhouse.