Skim resequencing finely maps the downy mildew resistance loci RPF2 and RPF3 in spinach cultivars whale and Lazio

Commercial production of spinach(Spinacia oleracea L.)is centered in California and Arizona in the US,where downy mildew caused by Peronospora effusa is the most destructive disease.Nineteen typical races of P.effusa have been reported to infect spinach,with 16 identified after 1990.The regular appearance of new pathogen races breaks the resistance gene introgressed in spinach.We attempted to map and delineate the RPF2 locus at a finer resolution,identify linked single nucleotide polymorphism(SNP)markers,and report candidate downy mildew resistance(R)genes.Progeny populations segregating for RPF2 locus derived from resistant differential cultivar Lazio were infected using race 5 of P.effusa and were used to study for genetic transmission and mapping analysis in this study.Association analysis performed with low coverage whole genome resequencing-generated SNP markers mapped the RPF2 locus between 0.47 to 1.46 Mb of chromosome 3 with peak SNP(Chr3_1,221,009)showing a LOD value of 61.6 in the GLM model in TASSEL,which was within 1.08 Kb from Spo12821,a gene that encodes CC-NBS-LRR plant disease resistance protein.In addition,a combined analysis of progeny panels of Lazio and Whale segregating for RPF2 and RPF3 loci delineated the resistance section in chromosome 3 between 1.18–1.23 and 1.75–1.76 Mb.This study provides valuable information on the RPF2 resistance region in the spinach cultivar Lazio compared to RPF3 loci in the cultivar Whale.The RPF2 and RPF3 specific SNP markers,plus the resistant genes reported here,could add value to breeding efforts to develop downy mildew resistant cultivars in the future.

Effects of Different Application Rates of Bioorganic Fertilizer on the Growth of Spinach in a Short Term

[Objectives]This study was conducted to promote the rational use of bioorganic fertilizers.[Methods]Stanley bioorganic fertilizer was selected to investigate the laws and characteristics of the effects of bioorganic fertilizer on spinach growth with different application rates in a short term and found out the precise application rate.[Results]As the application rate of bioorganic fertilizer increasing,the emergence rate of spinach decreased.The total weights and leaf areas of spinach plants treated with different application rates of bioorganic fertilizers were all higher than those of the control check(CK).The total weights and leaf areas of spinach plants applied with bioorganic fertilizer at different rates were all higher than those of the CK.The total weight of spinach plants increased linearly with the application rate of bioorganic fertilizer increasing among treatments,while the leaf area fluctuated with the increase of bioorganic fertilizer concentration among various treatments.The average root volumes and average diameters of treatments applied with bioorganic fertilizer at different rates were all higher than those in the CK,but the average root length showed a different trend.The average root length was higher in the CK than in various bioorganic fertilizer treatments in the early growth period,but the differences of various treatments from the CK gradually decreased in the middle period,and in the later period,the root length of spinach treated with organic fertilizer gradually exceeded the CK.[Conclusions]This study provides a theoretical basis for the rational application of bioorganic fertilizers in spinach production.

Effect of Nano-anatase TiO_2 on Spectral Characterization of PhotosystemⅡParticles from Spinach

The photosystem Ⅱ(PSⅡ) particles were purified by means of nano-anatase TiO_2 treatment of spinach and studied by spectroscopy. The results show that the electron transport and the oxygen-evolving rate of PSⅡ are accelerated after it has been treated with nano-anatase TiO_2; the UV-Vis absorption spectrum of PSⅡ particles is increased; the red shift of fluorescence emission peak of PSⅡ is 2 nm; the peak intensity is decreased; the PSⅡ signal Ⅱs of low temperature electron paramagnetic resonanace(EPR) spectrum is intensified under light, and the PSⅡ circular dichroism(CD) spectrum is similar to that of control. It is suggested that nano-anatase TiO_2 might bind to the PSⅡ reaction center complex and intensify the function of the PSⅡ electron donor, however, nano-anatase TiO_2 treatment does not change the configuration of the PSⅡ reaction center complex.

Effects of Rare Earth Elements on Vigor Enhancement of Aged Spinach Seeds

The effect and the mechanism of action of lanthanum, cerium and neodymium on aged seeds of spinach were studied. By LaCl_3, CeCl_3, and NdCl_3 treatment, the germination rate, germination index and vigor index of aged spinach seeds are increased and the activities of superoxide dismutase, catalase and peroxidase are enhanced. Moreover the ·O_2^- and malondialdehyde content are decreased and the cell membrane permeability of aged spinach seeds is reduced. Among these three rare earth elements, Ce treatment enhances vigor of aged seeds most significantly, that of Nd treatment secondly and La treatment is not as effective as the other two treatments. The reason may be from 4f electron characteristic and alternation valence of REEs.

Effects of 4f Electron Characteristics and Alternation Valence of Rare Earths on Photosynthesis: Regulating Distribution of Energy and Activities of Spinach Chloroplast

Chloroplasts were isolated from spinach treated with taCl3, CeCl3, and NdCl3. Because of owning 4f electron characteristics and alternation valence, Ce treatment presented the highest enhancement in light absorption, energy transfer from LHC Ⅱ to PS Ⅱ, excitation energy distribution from PS Ⅰ to PS Ⅱ, and fluorescence quantum yield around 680 nm. Compared with Ce treatment, Nd treatment resulted in relatively lower enhancement in these physiological indices, as Nd did not have alternation valence. La treatment presented the lowest enhancement, as La did not have either 4f electron or alternation valence. The increase in activities of whole chain electron transport, PS ⅡDCPIP photoreduction, and oxygen evolution of chloroplasts was of the following order： Ce〉Nd 〉La〉 control. However, the photoreduction activities of spinach PS I almost did not change with La, Ce, or Nd treatments. The results suggested that 4f electron characteristics and alternation valence of rare earths had a close relationship with photosynthesis improvement.

Effects of CeCl_3 on Energy Transfer and Oxygen Evolution in Spinach Photosystem Ⅱ

Due to 4f electron characteristics and alternation valence, cerium involved in an oxidation-reduction reaction in plant, closely relating to photosynthesis. Our studies proved that cerium could promote photosynthesis and greatly improve spinach growth. However, the mechanism of promoting energy transfer and conversion by cerium remains unclear. Here we reported that the effects of Ce^3＋ on energy transfer and oxygen evolution in photosystem Ⅱ （PS Ⅱ ） isolated from spinach, which was related to 4f electron characteristics and alternation valence in Ce molecule. The methods of absorption spectrum, fluorescence spectrum were used in the research. Results showed that Ce^3＋ treatment at low concentration could suitably change PS Ⅱ mieroenvironment, increase the absorbance of visible light, improve the energy transfer among amino acids within PS Ⅱ protein-pigment complex, and accelerate energy transport from tyrosine residue to chlorophyll a. In summary, the photochemical activity of PS Ⅱ （fluorescence quantum yield） and its oxygen evolving rate were enhanced by Ce^3＋.

Effect of Nd^(3+) on Photosynthesis of Spinach

The effect of Nd^(3+) on the photosynthesis and the growth of spinach was studied. The results show that Nd^(3+) improves the growth of spinach and increases chlorophyll content and photosynthetic rate. UV-Vis spectrum indicates that the Soret band of chl-a in spinach with NdCl_3 treatment is blue shifted by 2 nm, and the Q band is red shifted by 1 nm, and the ratio of Soret band intensity and Q band intensity increases. FT-IR spectra show that the peak of porphyrin ring in chl-a of spinach with NdCl_3 treatment is widened, suggesting that the formation of Nd^(3+)-chl-a. Treated by NdCl_3, the fluorescence emission peak of PSⅡ in spinach leaves is blue shifted by 12 nm and the intensity declines obviously, indicating that Nd^(3+) is bound to the PSⅡ protein-pigment complex and the electron transfer rate increases.

Accumulation of Rare Earth Elements in Spinach and Soil under Condition of Using REE and Acid Rain Stress

The content and distribution characteristics of REE in spinach and soil under using REE and acid rain stress were studied by pot experiments. The results show that the content of REE is 0 527～0 696 (μg·g -1 ) in the above ground portion of spinach, 2 668～3 003 (μg·g -1 ) in the under ground portion of spinach and 229 09～250 30 (μg·g -1 ) in the soil. With the acidity of acid rain increasing, the leaching of REE in plants and soil is strengthened and the amount of REE reduces with decreasing of pH value. After REE are used, though plants show the selective absorption to Ce group elements (especially spraying on leaves), regardless under acid rain stress or using REE or not, the distribution model of REE in the above ground and under ground portion of plants is basically the same with the control. Plants also follow the Oddo Harkins rule of the REE of distribution abundance, light rare earth elements is enriched, the minus of Eu is abnormal and admeasure of Ce is a rich model. The results show that REE in plants mainly come from soil and are affected by it.

Biomass Accumulation and Water Purification of Water Spinach Planted on Water Surface by Floating Beds for Treating Biogas Slurry

To find a new way treating the wastewater from biogas reactors in a pig farm, vegetated floating bed was built for observing the water-purifying capability of water spinach (Ipomoea aquatic) planted on the water surface. Experiments were carried out to record the growth and biomass accumulation of water spinach and its effect on purification of biogas wastewater. The results show that the water which mixed with biogas wastewater has been purified significantly by water spinach on the floating bed. During its growth season within four months, the overall length of water spinach reached 199 ± 35 cm, while its root length reached 63 ± 28.6 cm. The average weight of individual fresh plant is of 1285 ± 619.7 g. Meanwhile, the concentration of total nitrogen (TN) in water under the floating bed decreased from 8.9 ± 0.062 mg·L-1 to 0.5 ± 0.011 mg·L-1;the concentration of total phosphorus (TP) decreased from 4.4 ± 0.236 mg·L-1 to 0.92 ± 0.024 mg·L-1;the concentration of chemical oxygen demand (COD) decreased from 87.3 ± 6.68 mg·L-1 to 0.74 ± 0.46 mg·L-1. It suggests that the water spinach removed more than 90% of pollutants in terms of TN, TP, and COD from the water. Results show that the vegetated floating bed technique is a feasible way to dispose the biogas slurry.

Elevated Carbon Dioxide Level Suppresses Nutritional Quality of Lettuce and Spinach

Rising global CO2 levels are a major factor that impacts not only the environment but also many plant functions including growth, productivity and nutritional quality. The study examined the impact of elevated [CO2] on nutritional quality and growth characteristics of lettuce (Lactuca sativa) and spinach (Spinacia oleracea). Elevated [CO2] decreased the concentration of many important nutrients including nitrogen (protein), potassium and phosphorus in the edible parts of both lettuce and spinach. The nitrogen concentration in lettuce shoots was reduced by more than 30% at elevated [CO2] compared to the plants grown at ambient level of CO2. Similarly the concentration of a number of micronutrients including sulfur, zinc, copper and magnesium, was depressed in lettuce shoots. Although the total phenolic content and antioxidant capacity were higher in lettuce at elevated CO2, they were not affected in spinach. The photosynthetic activity was variable among the plant species while there was no increase in the carbon accumulation in these plants at elevated [CO2]. However, there was significant reduction in the leaf stomatal conductance in both lettuce and spinach in response to higher [CO2], which is likely affect both water loss from the leaves and their photosynthetic activity. The results indicate a broad adverse impact of rising [CO2] on the nutritional quality of commonly consumed leafy vegetables namely, lettuce and spinach.

Effects of Spinach Powder Fat-Soluble Extract on Proliferation of Human Gastric Adenocarcinoma Cells

Four kinds of assays were used to study the effect of a fat-soluble extract of spinach powder (SPFE) on the proliferation of human gastric adenocareinoma cell line (SGC-7901) in vitro.These studies included: (Ⅰ) cell growth assay, (Ⅱ) colony forming assay, (Ⅲ) MTT colorimetric assay, and (Ⅳ) 3H-TdR incorporation assay. The concentrations of SPFE expressed as the level of β-carotene in the medium were 2×10-8, 2×10-7 and 2×10-6 mol/L β-carotene in assays (Ⅰ)～(Ⅲ), but 4×10- 8, 4×10-7 and 4×10-6 mol/L β-caretene in assay (Ⅳ) respectively. The results indicated that SPFE inhibited the prolifendion and colony forming ability of SGC-7901 cells. And in MTT assay, SPFE inhibited the viability of SGC7901 cells, but no inhibitory effect of SPFE was observed on the viability of lymphocytes in peripheral blood of healthy people. Finally, in the 3H-TdR incorporation test, both SPFE and β-carotene showed significant inhibitory effects on DNA synthesis in SGC-7901 cells, but SPFE was more effective than β-carotene.

The Impacts on Spinach Growth and Yield by Biological Organic Fertilizer

To decrease fertilization amount of chemical fertilizer and improve the quality of vegetable crops,spinach was taken as the test material,and the impact of different fertilizer on spinach growth and yield was studied via the manners of biological organic fertilizer and organic fertilizer + chemical fertilizer. Experimental results showed that in the formula of organic fertilizer + chemical fertilizer,chlorophyll and nitrogen contents in spinach leaves obviously increased; in the formula of only adding organic fertilizer,spinach leaf temperature,leaf width,root length,plant height and fresh weight were all better than those in the formula of organic fertilizer + chemical fertilizer,and better formulas were A_5,E_5,F_3 and I_5,in which spinach plant height in E_5 was 5. 63 times higher than G_5,root length in E_5 was 2. 67 times higher than G_5,and fresh weight in G_5 was 32. 6 times higher than G_5. By comprehensive analysis,the most suitable formula for spinach production was E_5,and the research could provide theoretic basis for fertilization amount of organic fertilizer required by spinach growth and development.

Lead Remediation of Contaminated Water by Charcoal, LA Red Clay, Spinach, and Mustard Green

Lead is a toxic and naturally occurring substance with documented neurotoxin, toxic, and long-lasting adverse health effects globally. Lead exposure can cause impaired physical and mental development in children. Exposure to high lead levels affects the intestinal tract, kidneys, joints and reproductive system in adults. This study evaluates the removal of 1500 PPM of lead from contaminated aqueous solution using Celite, Louisiana Red Clay, Charcoal, and supernatants from aqueous extracts of Mustard Green (Brassica juncea), and Spinach (Spinacea oleracea). After shaking triplicate reaction mixtures for each substrate for 22 hours at room temperature, lead removal by the five substrates were analyzed by EPA Method 6010, using Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES). Results suggest that the order of lead removal is Spinach (98%) > Charcoal (96%) > LA Red Clay (88%) > Mustard Green (87%) > Celite (4%). The study concludes that liquid substrates such as the supernatants from pureed spinach and mustard green can effectively remove lead from contaminated water.

Cerium relieving the inhibition of photosynthesis and growth of spinach caused by lead

Chloroplasts were isolated from spinach cultured in lead chloride-present, Ce3+-administered, cerium chloride-administered lead chloride-present Hoagland’s media or that of Hoagland’s media. The experimental study demonstrated the effects of cerium (Ce) on distribution of light energy and photochemical activities of spinach chloroplast grown in lead (Pb)-present media. It was observed that Pb2+ significantly inhibited photosynthesis in spinach, including light absorption, energy transfer from LHCⅡ to photosystem Ⅱ, excitation energy distribution from photosystem I to photosystem Ⅱ, and transformation from light energy to electron energy and oxygen evolution of chloroplasts, and decreased spinach growth. However, Ce3+ treatment to Pb2+-present chloroplasts could obviously improve light absorption and excitation energy distribution in both photosystems and increase activity of photochemical reaction and oxygen evolution of chloroplasts. The results suggested that Ce3+ under Pb2+ stress could maintain the stability of chloroplast membrane, and improve photosynthesis of spinach chloroplast, thus promote spinach growth.

Research advances and prospects of spinach breeding,genetics,and genomics

Spinach(Spinacia oleracea)is a diploid(2n=2x=12),wind-pollinated and highly heterozygous crop.The plants are mostly dioecious,although some monoecious plants exist.Spinach is an economically important cool-season leafy vegetable crop.Demand for spinach is increasing worldwide,particularly due to its high nutritional content.Spinach is a versatile crop eaten raw or cooked and used as salads or mixed with other cuisines.This review article provides an overview of origin and domestication,genetic diversity and population structure,genetic and genomic resources,major diseases threatening spinach production,breeding progress,and synthesizing how these resources can help in spinach improvement.The rapid development of genomic and sequence resources of spinach has increased biological and genetics research and laid the foundation for adopting molecular breeding.Downy mildew is the most serious disease affecting spinach and breeding programs focus on developing cultivars resistant to continually emerging new races of downy mildew pathogens.The use of genomic and molecular resources and approaches offers promises in population improvement and hybrid development to address biotic and abiotic stresses production challenges and provide improved breeding materials and strategies against the rapidly changing pathogen races and climatic conditions.

Research Progress in Spinach (Spinacia oleracea L.) Germplasm Resources

Spinach is one of the main vegetable species.The study of spinach germplasm resources is beneficial to discovering excellent genes and accelerating the breeding efficiency,thereby further promoting the development of the spinach industry.In this study,the origin,propagation,collection,preservation,genetic diversity and breeding status of spinach were reviewed,and the problems and prospects of spinach germplasm resources were put forward.This paper provides reference for the research and breeding of spinach germplasm resources.

A Novel Convolutional Neural Networks Based Spinach Classification and Recognition System

In the present scenario,Deep Learning(DL)is one of the most popular research algorithms to increase the accuracy of data analysis.Due to intra-class differences and inter-class variation,image classification is one of the most difficult jobs in image processing.Plant or spinach recognition or classification is one of the deep learning applications through its leaf.Spinach is more critical for human skin,bone,and hair,etc.It provides vitamins,iron,minerals,and protein.It is beneficial for diet and is readily available in people’s surroundings.Many researchers have proposed various machine learning and deep learning algorithms to classify plant images more accurately in recent years.This paper presents a novel Convolutional Neural Network(CNN)to recognize spinach more accurately.The proposed CNN architecture classifies the spinach category,namely Amaranth leaves,Black nightshade,Curry leaves,and Drumstick leaves.The dataset contains 400 images with four classes,and each type has 100 images.The images were captured from the agricultural land located at Thirumanur,Salem district,Tamil Nadu.The proposed CNN achieves 97.5%classification accuracy.In addition,the performance of the proposed CNN is compared with Support Vector Machine(SVM),Random Forest,Visual Geometry Group 16(VGG16),Visual Geometry Group 19(VGG19)and Residual Network 50(ResNet50).The proposed provides superior performance than other models,namely SVM,Random Forest,VGG16,VGG19 and ResNet50.

Influence of Synthetic Antioxidants on Extraction of All-<i>trans</i>-Lutein from Spinach under Air and Nitrogen Atmosphere

Extraction is most commonly used sample preparation technique in quantitative determination of all-trans-lutein in spinach. In our study RP-HPLC was applied to identify the constituents of spinach extract and to quantify all-trans-lutein content with the mobile phase consisted of acetone and water. Due to sensitivity of all-trans-lutein, we compared effects of different extraction conditions;air and nitrogen atmosphere and ethanol, ethanol with added 0.1% TBHQ and ethanol with added 0.1% BHT as solvents. Results for the all-trans-lutein content in the spinach samples and spinach samples with standard addition obtained in air and in nitrogen confirmed the induced degradation of all-trans-lutein in oxygen from the air. Ethanol containing synthetic antioxidant TBHQ under nitrogen atmosphere gave the highest yield of extraction and recovery of all-trans-lutein from spinach.

Spinach aldolase interactions with rabbit, chicken, and fish muscle phosphofructokinase-1

Previous studies showed that rabbit muscle phosphofructokinase-1 (PFK-1) activity losses due to dilution, due to inhibition by ascorbate, and due to some lithium salts were prevented by rabbit muscle aldolase. Chicken PFK-1 and fish PFK-1 interacted with ascorbate and were inhibited, consistent with a previously proposed function that ascorbate facilitates glycogen in resting muscle by inhibiting glycolysis. This report shows that a plant enzyme, spinach aldolase, has the same ability to prevent rabbit muscle PFK-1 activity loses as rabbit muscle aldolase and in some instances it was a better protector from activity losses than rabbit aldolase. Spinach aldolase also protected chicken and fish PFK-1s from inhibitions by ascorbate and from activity losses due to dilution. Prevention of losses PFK-1 activities from animal species by a plant protein, spinach aldolase, suggests an evolutionary conservative relationship between PFK-1s and aldolases.

Minor alleles are associated with white rust(Albugo occidentalis)susceptibility in spinach(Spinacia oleracea)

Minor alleles(MA)have been associated with disease incidence in human studies,enabling the identification of diagnostic risk factors for various diseases.However,allelic mapping has rarely been performed in plant systems.The goal of this study was to determine whether a difference in MA prevalence is a strong enough risk factor to indicate a likely significant difference in disease resistance against white rust(WR;Albugo occidentalis)in spinach(Spinacia oleracea).We used WR disease severity ratings(WR-DSRs)in a diversity panel of 267 spinach accessions to define resistant-and susceptibility-associated groups within the distribution scores and then tested the single-nucleotide polymorphism(SNP)variants to interrogate the MA prevalence in the most susceptible(MS)vs.most resistant(MR)individuals using permutation-based allelic association tests.A total of 448 minor alleles associated with WR severity were identified in the comparison between the 25%MS and the 25%MR accessions,while the MA were generally similar between the two halves of the interquartile range.The minor alleles in the MS group were distributed across all six chromosomes and made up~71%of the markers that were also strongly associated with WR in parallel performed genome-wide association study.These results indicate that susceptibility may be highly determined by the disproportionate overrepresentation of minor alleles,which could be used to select for resistant plants.Furthermore,by focusing on the distribution tails,allelic mapping could be used to identify plant markers associated with quantitative traits on the most informative segments of the phenotypic distribution.