Development and Evaluation of a Loop-mediated Isothermal Amplification Assay for the Rapid Detection and Identification of Pectobacterium carotovorum on Celery in the Field

Pectobacterium carotovorum is the causal agent of bacterial soft rot in a wide range of vegetable host species.Once P.carotovorum infects the plant,the spread of the disease is difficult to control.In this study,a rapid and sensitive method based on loop-mediated isothermal amplification(LAMP)was developed for detecting P.carotovorum in celery with soft rot using a primer set designed from the pmrA conserved sequence of P.carotovorum.The specificity of the LAMP primer set for P.carotovorum was extensively validated on both P.carotovorum strains and nontarget strains.The sensitivity was 1 pg of P.carotovorum genomic DNA,which demonstrated 10 times more sensitive than the conventional PCR assay.LAMP was also used to detect P.carotovorum in bacterial suspension.The lowest detection concentration was 104 CFU·mL^−1.In addition,a LAMP assay,in conjunction with a crude DNA extraction method,was successfully performed on P.carotovorum-infected samples derived from both artificially and naturally infected plants.In summary,the LAMP assay established in this study constitutes a simple,sensitive,and rapid method for the detection of P.carotovorum,and has potential application in the control of celery soft rot disease through early detection.

基于Celery和Django的分布式自动化测试系统设计

为了实现快速高效使用计算集群解决大量测试用例管理和执行的问题,文中提出了一种基于Celery和Django的分布式自动化测试系统。该系统提出了由API服务器层、用例管理层、任务调度层和任务执行层组成四层架构,详细描述了每层的功能和具体实现。该系统实现了用例的管理、分布式执行、失败重试等功能。该系统能够快速部署和配置测试执行节点,实现了充分利用计算集群资源、提高测试效率的目的。

Analysis of Genetic Relationship among Celery Germplasms by RAPD

In this study, forty celery cultivars introduced from different regions of China were used as experimental materials to verify and analyze the practicability of RAPD technology in the identification of celery cuhivars. The results showed that RAPD technology could distinguish accurately the genetic relationship among various celery cultivars as a simple and ideal DNA molecular marker technology suitable for genetic relationship analysis. To be specific, 13 RAPD primers with clear amplified bands and significantly different number of amplified bands were screened, which provided basis for the identification of genetic relationship among different celery cultivars.

Effects of Different Drip Irrigation Fertilizers on Nutrient Levels in Celery and Soil under Drip Irrigation

This study was conducted to investigate the effects of different fertilizers on nitrogen, phosphorus and potassium ＇absorption and distribution by celeo, and the changes of soil nutrients in the 0 -40 cm soil layer under drip irrigation, so as to provide a theoretical basis for nutrient management of greenhouse celery culti- vation and special fertilizer development. With celery as an experiment material and the ratio of conventional fertilization as control treatment, the effects of different ratios of nitrogen, phosphorus and potassium on nutrient absorption by celery and changes of soil nutrients were investigated by plot experiment in greenhouse. The results showed that the contents and distribution proportions of N and P in leaf were higher than those in stem, while for K, the content and distribution proportion were higher in stem than in leaf. The absorption amount of K was the highest in celery, followed by N, and the absorption amount of P element was the least. The mean ratio of N, P and K in celery was 1：0.556： 1.609. There were evident dynamic changes in contents of soil available nutrients in the 0 -20 cm soil layer in various growth stages of celery under different drip irrigation fertilizers. The contents of soil available nutrients were higher on the 28＇h , 47~ and 83＇h d ＂after fieht planting, while those before field planting and after harvest were lower. So the amounts of soil available nutrients were closely related to the growth stage of celery. In the whole growth period of celery, the mean input amounts of N, P205 and K20 were 805, 1 049 and 916 kg/hm2 , respectively, but the absorption amounts of nutrients by celery were far less than inputs, and the amounts of N, P205 and K20 absorbed by celery＂ were only 23% -26% , 10% and 31% -35% of the appli- cation amounts, respectively. The apparent balance of N, P2 O5 and Kz O were 613,943 and 609 kg/hm2 , respectively, indicating excess fertilization in this experi- ment. Under this experiment condition, Tj （ N： PzOs： K20 = 1 ： 0.63： 1.08） favored increase of celery yield and absorption of nitrogen, phosphorus and petassium by celery. The results will provide a scientific basis for study and utilization of special fertilizer for drip irrigation on celery. Key words Drip irrigation; Fertilizer for drip irrigation; Celery; Soil nutrient; Apparent balance

Clustering Analysis on the Climatic Conditions in Hundreds of Kilometers of Celery Belts in Hulu River Valley

By using climate data in national stations in Xiji County,Ningxia during 1981 and 2020,a regression analysis was carried out on weather data in crop growth season in three automatic weather stations in Hulu River Valley. The results showed that celery belts of Hulu River Valley was divided into two groups: early-maturing region of south Xinglong-Xiaohe where is warm and rainy,serotinous region of north Jiqiang-Xinying where is warm and cold and rainless. Four subregions: Xinlong,Xiaohe,Jiqiang,Xinying. Each sub-region was divided into five regions according to climate layer and observation in growth season: temperature accumulating planting period,low temperature seedling period,suitable temperature for external leaf growth stage,high-temperature for celery mulching-sanded plantation in different sowing periods, water and fertilizer,insect prevention,time to market sales.

Effects of topdressing ratio and frequency on the dry matter, yield, and quality of tomato and celery under a small amount of continuous subsurface drip irrigation

Compared with conventional full irrigation,the existing water-saving irrigation method achieves the purpose of water saving by actively controlling soil moisture.High-frequency irrigation can make the ideal conditions for soil water movement and root absorption of water and nutrients.This research used a plot experiment in a greenhouse and set up different fertilization amounts and frequencies during the growth stage to study the effects of small-amount and continuous subsurface drip irrigation on the dry matter,yield,and quality of tomato and celery.The results showed that the frequency of topdressing had a great influence on the dry matter accumulation of tomatoes,and the amount of topdressing had little effect on the fresh weight of the upper part of a tomato plant.The application of high-frequency fertilizer increased the dry matter accumulation in the underground part of the tomato.Under the premise given amount of total fertilization,the growth rate and yield of tomatoes were positively correlated with the amount of topdressing.The optimum fertilization frequency was 1 time during the first fruit stage,3 times for the second fruit stage,and 5 times for the third fruit stage,the yield during the fourth stage was increased with higher frequency,and the topdressing was started ahead of the fourth fruit stage when the diameter of fruit was 40 mm.The lower fertilization frequency during the early stage and higher fertilization frequency during the later stage can increase the yield of celery.The higher ratio of topdressing,the higher frequency during the early growth stage,and the lower frequency during the later stage can achieve the best quality of celery.

Bioaccumulation and translocation of cadmium in cole (Brassica campestris L.) and celery (Apium graveolens) grown in the polluted oasis soil,Northwest of China

A pot experiment was conducted to study the bioaccumulation and translocation of cadmium （Cd） in cole （Brassica campestris L.） and celery （Apium graveolens） grown in the Cd-polluted oasis soil, Northwest of China. The results showed that Cd in the unpolluted oasis soil was mainly bound to carbonate fraction （F2） and Fe-Mn oxide fraction （F3）. However, marked change of Cd fractions was observed with increasing soil Cd concentrations, in which the concentration of Cd in F1 （exchangeable fraction）, F2 and F3 increased significantly （p 〈 0.001 for F1, F2 and F3）. The growth of cole and celery could be facilitated by low concentrations of Cd, but inhibited by high cortcentmdons. The correlation analysis between the fraction distribution coefficient of Cd in the soil and Cd concentration accumulated in the two vegetables showed that Cd in F1 in the soil made the greatest contribution on the accumulation of Cd in the two vegetables. The high bio-eoncentration factor and the translocation factor of Cd in both cote and celery were observed, and Cd had higher accumulation in the edible parts of the two vegetables. Therefore, both cole and celery grown in Cd-polluted oasis soil have higher risk to human health. And the two vegetables are not suitable to be cultivated as vegetables consumed by human in the Cd-polluted oasis soil.

Dynamic changes in soil chemical properties and microbial community structure in response to different nitrogen fertilizers in an acidified celery soil

To determine the effects of different kinds of nitrogen fertilizer,especially high-efficiency slowrelease fertilizers,on soil pH,nitrogen(N)and microbial community structures in an acidic celery soil,four treatments(CK,no N fertilizer;NR,urea;PE,calcium cyanamide fertilizer;and SK,controlled-release N fertilizer)were applied,and soil pH,total soil N,inorganic N,and soil microbial biomass C were analyzed.Phospholipid fatty acids(PLFAs)were extracted and detected using the MIDI Sherlock microbial identification system.The PE treatment significantly improved soil pH,from 4.80 to>6.00,during the whole growth period of the celery,and resulted in the highest celery yield among the four treatments.After 14 d application of calcium cyanamide,the soil nitrate content significantly decreased,but the ammonium content significantly increased.The PE treatment also significantly increased soil microbial biomass C during the whole celery growth period.Canonical variate analysis of the PLFA data indicated that the soil microbial community structure in the CK treatment was significantly different from those in the N applied treatments after 49 d fertilization.However,there was a significant difference(P<0.05)in soil microbial community structure between the PE treatment and the other three treatments at the end of the experiment.Calcium cyanamide is a good choice for farmers to use on acidic celery land because it supplies sufficient N,and increases soil pH,microbial biomass and the yield of celery.

Identification and quantification of benzimidazole metabolites of thiophonate-methyl sprayed on celery cabbage using SiO_2@NiO solid-phase extraction in combination with HPLC-MS/MS

Thiophonate-methyl(TPM) is one of fungicides and pesticides widely used in agriculture field.However,the residue of its benzimidazole(BZD) metabolites in related agricultural products poses a potential risk to consumers.In this paper,nickel oxide nanoparticle-deposited silica(SiO_2@NiO) composite was used for the selective enrichment and purification of TPM's BZD metabolites in celery cabbage sprayed with TPM.Meanwhile,high-performance liquid chromatography coupled with precursor ion scan-mass spectrometry(HPLC-PIS-MS) and high-resolution MS/MS analysis(HR-MS/MS) was utilized for their qualitative and quantitative analysis.Twenty-one potential TPM's BZD metabolites were found and four of them were identified.One metabolite was discovered for the first time.Besides,a robust and sensitive quantitative method was developed with good linearities(R^2> 0.9972) within a wide range of 10.00-1000 ng/g.The detection limits of three known TPM's metabolites were within the range of 3.20-4.90 ng/g.Relative standard deviations(RSDs) of intra-day and inter-day precisions were less than 18.3%,which showed perfect reproducibility.The method was successfully applied to monitoring TPM's BZD metabolites in celery cabbage sprayed with TPM and the concentration versus time curves of TPM's metabolites in celery cabbage were plotted.This method is expected to be used to monitor BZD residues in various fruits and vegetables.

Comparative metabolomics provides novel insights into the basis of petiole color differences in celery(Apium graveolens L.)

Plant metabolites are important for plant development and human health.Plants of celery(Apium graveolens L.)with different-colored petioles have been formed in the course of long-term evolution.However,the composition,content distribution,and mechanisms of accumulation of metabolites in different-colored petioles remain elusive.Using ultra-high performance liquid chromatography-tandem mass spectrometry(UHPLC-MS/MS),1159 metabolites,including 100 lipids,72 organic acids and derivatives,83 phenylpropanoids and polyketides,and several alkaloids and terpenoids,were quantified in four celery cultivars,each with a different petiole color.There were significant differences in the types and contents of metabolites in celery with different-colored petioles,with the most striking difference between green celery and purple celery,followed by white celery and green celery.Annotated analysis of metabolic pathways showed that the metabolites of the different-colored petioles were significantly enriched in biosynthetic pathways such as anthocyanin,flavonoid,and chlorophyll pathways,suggesting that these metabolic pathways may play a key role in determining petiole color in celery.The content of chlorophyll in green celery was significantly higher than that in other celery cultivars,yellow celery was rich in carotenoids,and the content of anthocyanin in purple celery was significantly higher than that in the other celery cultivars.The color of the celery petioles was significantly correlated with the content of related metabolites.Among the four celery cultivars,the metabolites of the anthocyanin biosynthesis pathway were enriched in purple celery.The results of quantitative real-time polymerase chain reaction(q RT-PCR)suggested that the differential expression of the chalcone synthase(CHS)gene in the anthocyanin biosynthesis pathway might affect the biosynthesis of anthocyanin in celery.In addition,HPLC analysis revealed that cyanidin is the main pigment in purple celery.This study explored the differences in the types and contents of metabolites in celery cultivars with different-colored petioles and identified key substances for color formation.The results provide a theoretical basis and technical support for genetic improvement of celery petiole color.

Differences of cadmium absorption and accumulation in selected vegetable crops

A pot experiment and a sandy culture experiment grown with three vegetable crops of Chinese cabbage ( B. chinensis L., cv. Zao\|Shu 5), winter greens ( B.var.rosularis Tsen et Lee, cv. Shang\|Hai\|Qing) and celery ( A.graveolens L. var. dulce DC., cv. Qing\|Qin) were conducted, respectively. The initial soil and four incubated soils with different extractable Cd (0.15, 0.89, 1.38, 1.84 and 2.30 mg Cd/kg soil) were used for the pot experiment. Five treatments were designed (0, 0.0625, 0.125, 0.250 and 0.500 mg Cd/L) in nutrient solution in the sandy culture experiment. Each treatment in pot and sandy culture experiments was trireplicated. The objectives of the study were to examine Cd accumulation in edible parts of selected vegetable crops, its correlation with Cd concentrations in vegetable garden soil or in nutrient solution, and evaluate the criteria of Cd pollution in vegetable garden soil and in nutrient solution based on the hygienic limit of Cd in vegetables. Cadmium concentrations in edible parts of the three selected vegetable crops were as follows: 0.01—0.15 mg/kg fresh weight for Chinese cabbage, 0.02—0.17 mg/kg fresh weight for winter greens, and 0.02—0.24 mg/kg fresh weight for celery in the pot experiment, and 0.1—0.4 mg/kg fresh weight for Chinese cabbage, 0.1—1.4 mg/kg fresh weight for winter greens, and 0.05—0.5 mg/kg fresh weight for celery in the pot experiment(except no\|Cd treatment). The order of the three test vegetable crops for cadmium accumulation in the edible parts was celery>winter greens>Chinese cabbage in both the pot experiment and the sandy culture experiment. Cadmium accumulation in edible parts or roots of the vegetable crops increased with increasing of cadmium concentration in the medium(soil or nutrient solution). And cadmium concentrations in edible parts of the test vegetable crops were significantly linearly related to the Cd levels in the growth media (soil and nutrient solution). Based on the regression equations established and the limit of cadmium concentration in vegetable products, the thresholds of Cd concentration in the growth medium evaluated was as follows: 0.5 mg/kg soil of extractable Cd for soil and 0.02 mg /L for nutrient solution. The high capacity for cadmium accumulation in the edible parts of different vegetable crops together with the absence of visual symptoms implies a potential danger for humans.