Zhanjiang City Research Articles

Marivirga aurantiaca sp. nov., a halophilic nitrite-reducing bacterium, isolated from intertidal surface sediments

A novel Gram-stain-negative strain, designated S37H4T, was isolated from an intertidal surface sediment sample collected from Zhanjiang City, Guangdong province, south PR China. Cells of the strain were aerobic, non-flagellated, long rod-shaped and motile by gliding. S37H4T could grow at 4–40 °C, pH 7.0–8.5 and in 2.0–15.0 % NaCl, with optimal growth at 25–30 °C, pH 7.5 and 9.0 % NaCl, respectively. S37H4T was capable of nitrite removal under high-salt conditions, and there were three denitrification genes, nirK, norB and nosZ, in its genome. The results of phylogenetic analyses based on the 16S rRNA gene and genome sequences indicated that S37H4T represented a member of the genus Marivirga and formed a subclade with Marivirga lumbricoides JLT2000T. S37H4T showed the highest 16S rRNA sequence similarity to M. lumbricoides JLT2000T (98.3 %) and less than 97.0 % similarity with other type strains of species of the genus Marivirga . The average nucleotide identity (ANI) and digital DNA–DNA hybridization (dDDH) values between S37H4T and the reference type strains of species of the genus Marivirga were 70.7–74.3 % and 18.2–19.2 %, respectively. The major fatty acids of S37H4T were iso-C15 : 0, iso-C15 : 1G, iso-C17 : 0 3-OH and summed feature 3 (C16 : 1ω6c and/or C16 : 1ω7c). The major respiratory quinone of this novel strain was MK-7, and the predominant polar lipids were identified as phosphatidylethanolamine, an unidentified aminolipid, an unidentified phospholipid and three unidentified lipids. The results of analyses of phylogenetic, genomic, physiological and biochemical characteristics indicated that S37H4T represented a novel species of the genus Marivirga , for which the name Marivirga aurantiaca sp. nov. is proposed. The type strain is S37H4T (= GDMCC 1.1866T = KACC 21922T).

Building a Modern Industrial System to Promote High-quality Economic Development in Zhanjiang

The modern industrial system is the material foundation and strategic focus of the socialist market economy system, and is an inherent requirement for achieving high-quality economic development. Studying and exploring how to build a modern industrial system is of great practical significance for accelerating the construction of a new development pattern and promoting high-quality economic development. This article takes Zhanjiang City, Guangdong Province as an example to summarize and extract the prominent contradictions faced by the Zhanjiang industrial system, clarify the development ideas of the modern industrial system, and propose the need to use systematic thinking to integrate new development concepts into the construction process of the modern industrial system. From expanding the economic volume, accelerating the pace of digital economy development, building a marine financial center, improving the level of opening up to the outside world, building a strong city with innovative talents, and improving regional cooperation mechanisms Propose implementation paths for building a modern industrial system from seven aspects, including granting greater financial rights, to provide support for high-quality economic development in Zhanjiang.

First Report of Colletotrichum siamense causing Anthracnose on Ficus microcarpa in China.

Chinese banyan, Ficus microcarpaLinn. f. (Moraceae), is a native and popular landscape tree with highornamentalandeconomicvalue in South China. In May 2018, a foliar disease occurred on F. Microcarpa in Zhanjiang city (21˚17'51''N, 110˚18'16''E), Guangdong Province, China. Theincidenceof thediseasewas 10%andseveritywas 20% (n = 100 investigated plants). Symptoms first appeared on leaves as small black spots (up to 5 mm diam) with yellow haloes. The spots gradually enlarged in size and coalesced, resulting in necrosis and early shedding of the leaves. Ten symptomatic leaves from 10 plants were collected. The margins of the samples were cut into small pieces (5 × 5 mm), surface disinfected (75% ethanol 30 s, 0.1% HgCl2 45 s, rinsed 3 times with sterile distilled water), and placed on potato dextrose agar (PDA) at 28°C with a photoperiod of 12 h. After 5 days, a total of four isolates with 100% isolation frequency were obtained and three representative strains (T6, T6-1, and T6-2) were used for morphological and molecular characterization. Colonies on PDA were white to gray with cottony mycelia, a few bright orange conidial masses developed near the inoculum point. Conidia were single-celled, smooth-walled, straight, colorless, fusiform with obtuse to slightly rounded ends, and measured 13.2 to 17.5 (avg. 15.3) × 4.3 to 6.0 (avg. 5.2) μm in size (n = 50). Appressoria were oval to irregular in shape, dark brown, and ranged from 5.8 to 9.1 (avg. 7.5) × 4.8 to 6.5 (avg. 5.6) µm (n = 50). Morphological characteristics of the isolates agreed with the description of Colletotrichum siamense (Prihastuti et al. 2009). The ITS (Nos. MK225610, ON979519, ON979520), TUB2 (Nos. MK348533, OQ130408, OQ130409), ACT (Nos. MZ852755, OQ116933, OQ116934) andGAPDH (Nos. MZ852756, OQ130406, OQ130407) sequences were 99.35%, 98.76%, 98.92% and 97.60% identical to the type C. siamensestrain MFLU 090230 (accession nos. NR_144784, FJ907438, FJ907423 and FJ972575) through BLAST analysis, respectively. A phylogenetic tree was generated using the concatenated sequences of ITS, ACT, GAPDH and TUB2. The result showed that the 3 isolates were clustered with C. siamense strains including the type MFLU 090230. To perform pathogenicity tests, One leaf (wounded and/or unwounded) per seedling (n = 20, 2-year-old) was inoculated by dropping a 10 ul droplet of the conidial suspension (1 × 105) of isolate T6 or sterile distilled water (as control) at one point, respectively. These plants were wrapped in polyethylene bags for 2 days and incubated in a greenhouse at 28± 2°C with 80-90% relative humidity. Initial symptoms appeared within 5 days on all wounded and unwounded inoculated leaves, while the controls remained symptomless. Colletotrichum siamense was reisolated from the lesions in terms of morphology and molecular characterization, whereas no fungus was isolated from control leaves. The pathogenicity test was repeated three times under the same conditions. The diseases caused by C. siamense have been reported to cause anthracnose in a wide range of hosts (Weir et al. 2012), but not in F. microcarpa. In China, C. gloeosporioides has been reported to cause anthracnose on potted banyan F. microcarpa (Yao et al. 2016), but not C. siamense. This is the first report of C. siamense causing anthracnose on F. microcarpa in China.This study provides valuable information for the identification and control of the anthracnose on F. microcarpa.

Analysis of Economic Indicators in Zhanjiang City during Epidemic Period Based on Remote Sensing Light Index

GDP (Gross Domestic Product) reflects the economic power and market scale of a city, offering an important reference for political decision-making and national development. The luminous remote sensing plays an important role in exploring the city economic development, analyzing and forecasting urban GDP. The luminous remote sensing is a new method to evaluate and display macro issues of economic and social development. This article analyzes the correlation between the lighting index and the economic index GDP, and constructs the best linear regression model of the economic index of Zhanjiang, considering the impact of the Covid-19. Based on the regression slope of night light intensity before and after the Covid-19, this article analyzes the economic trend of Zhanjiang during the epidemic period. The results show that there is a significant linear correlation between the night light index and the socio-economic index, and the regression slope of the light can reflect the short-term economic trend and evaluate the city-level economic indicators well.

A Management Model to Operate a Commercial Tennis Club in Zhanjiang, China

Background and Aim: After the Beijing Olympic Games in 2008, tennis was rapidly developing in China. In 2021. China's tennis population has risen to the second largest in the world but it has only 800 tennis clubs out of the total 115,584 tennis clubs in the world, and in Zhanjiang City, only 17 tennis clubs are operating for commercial purposes. The result of surveying the needs assessment among the customers showed that there was a wide gap between observed perceptions and expectations in many issues in service management operations, which means that the customers were not satisfied with the club's operations. The researchers were interested in studying these issues to find customers’ needs and suggestions to improve the tennis clubs' service and management in this area by applying service quality and marketing mix strategies. The objectives: (1) to develop a management model to operate commercial tennis clubs in Zhanjiang City, China, based on service quality and marketing mix concepts (2) to confirm the model’s satisfaction, appropriateness, and practicality of the developed management model. Materials and Methods: This research was a research and development research. The data collection was 1) Interviews with the managers or representatives of the 17 clubs, 2) a survey of the 398 clubs’ customers with a dual response questionnaire, and 3) The consensus with 19 experts by Delphi. 4) a focus group discussion with 11 stakeholders. The research tools were a structured form for interviews, a dual response questionnaire, a questionnaire for consensus with a Delphi, and a form for recording the focus group discussion. The data was analyzed in descriptive, content analysis, and PNI modified by the use of SPSS. Results: The clubs should 1) set the positioning of the clubs 2) set vision, goals, and missions to be the direction of a club’s management, 3) set the division of works to share and understand the scope of duty and responsibility of each section, 4) consider the staff motivation and welfare, service quality 5) create operation manuals, and job descriptions, collecting data to improve the service quality 6) applying marketing to create strategies such as; offering a variety of products, pricing at the same rate of other clubs, set the easy and convenient operation process for customers.7) Collect the problems and needs of customers, and the readiness of management resources, to formulate the management strategies with the application of service quality and marketing mix concepts which could respond to expectations them Conclusion: The clubs should consider management functions and marketing mixes to create the strategies to operate the clubs by the responses to the needs of customers survey.

Occurrence and Genotypic Identification of Blastocystis spp., Enterocytozoon bieneusi, and Giardia duodenalis in Leizhou Black Goats in Zhanjiang City, Guangdong Province, China.

Blastocystis spp., Enterocytozoon bieneusi, and Giardia duodenalis are three common zoonotic intestinal parasites that cause severe diarrhea and enteric diseases. Leizhou black goats are characterized by a high reproductive rate, fast growth, and good meat quality, making them one of the pre-eminent goat breeds in China. Goats are reportedly common reservoirs of these three intestinal pathogens, but no information on their prevalence or genotypic distributions in black goats in Guangdong Province, China, is available. A total of 226 fecal samples were collected from goats in Zhanjiang city and genomic DNA was extracted from them. The presence of the three pathogens was detected using nested PCR targeting the sequences encoding SSU rRNA (Blastocystis spp.), the internal transcribed spacer of rRNA (ITS; E. bieneusi), as well as beta-giardin, glutamate dehydrogenase, and triosephosphate isomerase (G. duodenalis). All PCR products were sequenced to determine the species and genotypes of the organisms. The total prevalence rates of Blastocystis spp., E. bieneusi, and G. duodenalis were 33.63% (76/226), 17.70% (40/226), and 24.78% (56/226), respectively. Four subtypes of Blastocystis spp. were detected: ST5 (n = 6), ST10 (n = 50), ST14 (n = 14), and ST21 (n = 6). Among them, ST10 was the dominant genotype, accounting for 65.79% of strains, followed by the genotypes ST14 (18.42%), zoonotic ST5 (7.89%), and ST21 (7.89%). Four genotypes of E. bieneusi were detected: CHG3 (n = 32), CM21 (n = 4), CHG1 (n = 2), and ET-L2 (n = 2). Among these, CHG3 was the dominant genotype. Assemblage E (n = 54) and concurrent assemblages A and E (n = 2) were identified in the G. duodenalis-positive goats using multilocus genotyping. Blastocystis spp., E. bieneusi, and G. duodenalis infections were common in Leizhou black goats, all of which have zoonotic genotypes, indicating the potential risk of zoonotic transmission. Our results provide basic data for the prevention and control of these three intestinal pathogens. Further studies are required to better understand their genetic characteristics and zoonotic potential in Guangdong Province.

Factors Influencing the Driving Force of Innovative Talents and the Optimization Matching of Talent Policies in Zhanjiang City

This article conducts a study on the relationship between internal and external driving forces of innovative talents and their innovative behavior in Zhanjiang City, using theories such as the theory of intrinsic motivation and social cognitive theory. It establishes and verifies a mediating model of internal driving force in the relationship between external driving forces and innovative behavior. The study focuses on innovative talents in industries such as education, research institutions, and key enterprises in Zhanjiang City, and distributes questionnaires to collect data. Descriptive analysis, reliability and validity testing, regression analysis, factor analysis, and structural equation modeling are conducted using SPSS 19.0 and AMOS 26.0 to study the influencing factors of talent's internal driving force in Zhanjiang City. The study concludes that innovative behavior is influenced by both external driving forces and internal driving force, and that internal driving force partially mediates the relationship between external driving forces and innovative behavior. Based on the analysis results, improvement measures and suggestions are proposed.

Study on the Path Strategy of Zhanjiang City to Build a Modern Coastal Economic Belt

As a coastal city in Guangdong Province, Zhanjiang, with its unique geographical location and natural conditions, has become a focal point for building a modern coastal economic belt. This paper focuses on the path strategy of Zhanjiang City to build a modernized coastal economic belt and discusses the current situation, advantages, and opportunities of Zhanjiang City’s economic development.

Identification and pathogenicity of Aurifilum species (Cryphonectriaceae, Diaporthales) on Terminalia species in Southern China.

The family of Cryphonectriaceae (Diaporthales) contains many important tree pathogens and the hosts are wide-ranging. Tree species of Terminalia were widely planted as ornamental trees alongside city roads and villages in southern China. Recently, stem canker and cracked bark were observed on 2-6 year old Terminalianeotaliala and T.mantaly in several nurseries in Zhanjiang City, Guangdong Province, China. Typical conidiomata of Cryphonectriaceae fungi were observed on the surface of the diseased tissue. In this study, we used DNA sequence data (ITS, BT2/BT1, TEF-1α, rpb2) and morphological characteristics to identify the strains from Terminalia trees. Our results showed that isolates obtained in this study represent two species of Aurifilum, one previously described species, A.terminali, and an unknown species, which we described as A.cerciana sp. nov. Pathogenicity tests demonstrated that both A.terminali and A.cerciana were able to infect T.neotaliala and two tested Eucalyptus clones, suggesting the potential for Aurifilum fungi to become new pathogens of Eucalyptus.

Spatio-temporal variation and prediction of ecological quality based on remote sensing ecological index – a case study of Zhanjiang City, China

A significant portion of Zhanjiang City’s ecological land areas have been reduced as a result of the city’s growing urbanization, which has caused the city’s ecological environment quality to decline. In order to monitor the quality of the ecological environment, the remote sensing ecological index (RSEI) is frequently utilized. In this study, the Landsat series satellite images from 2000, 2005, 2009, 2015, and 2020 were used. The Normalized Differential Vegetation Index (NDVI), Wetness (WET), Normalized Differential Build-up and bare Soil Index (NDBSI), and Land Surface Temperature (LST) were the four indicators utilized in the RSEI to quantitatively evaluate the changes in ecological environment quality in Zhanjiang City. The results are as follows. (1) The mean RSEI values for the years 2000, 2005, 2009, 2015, and 2020 are, respectively, 0.579, 0.597, 0.597, 0.607, and 0.601. In addition, the overall ecological environment of Zhanjiang is very good. In terms of spatial differences, the ecological environment quality in the central and southeastern parts of Zhanjiang is significantly higher than that in other areas, while the ecological environment quality in its coastal town areas is much worse. The lower RSEI index of developed land in coastal areas proves that the RSEI index can reflect the deterioration of the urban environment in coastal areas from 2000 to 2020. Therefore, the RSEI can be used to evaluate the ecological environment quality of Zhanjiang City. (2) The ecological environment changes in the study area are “substantially better,” “better,” “no change,” “worse,” and “much worse,” respectively, according to the difference in RSEI processed between 2000 and 2020. These changes were 38.38, 6,047, 13.93, 6.65, and 34.58%. The percentage of ecological environmental quality in Zhanjiang City that has become better is higher than that has become worse. This indicates that the quality of ecological environment in Zhanjiang City has improved between 2000 and 2020. (3) The regression produced the following equation for the association, which was significant at the 0.053 level: 100*Rsei = 154.69–1.18*IS(R = 0.66). The remote sensing ecological index for Zhanjiang in 2035 is 0.488 when the city’s planned population and area are added together.

Inspection of IMERG precipitation estimates during Typhoon Cempaka using a new methodology for quantifying and evaluating bias

Bias analysis is a significant component in the performance evaluation of satellite precipitation products (SPPs), and the relative bias (RB) is usually adopted as a key metric in all relative studies. However, when calculating the RB, severe overestimation (positive RB) and underestimation (negative RB) with the opposite sign can be offset through summation when a small temporal scale changes to a large temporal scale, and the final result will ignore the actual situation, which weakens the validity and reliability of bias evaluation. To solve the above problem, the typhoon presenting capability (TPC), which consists of two metrics, the presenting capability indicator (PCI) and the bias type discriminant (BTD), was developed as a new methodology for error evaluation during tropical cyclone events. In this study, by applying the TPC, two quasi-real-time Integrated multi-satellite retrievals for global precipitation measurement (IMERG) products (i.e., the early run and late run) acquired during Typhoon Cempaka in July 2021 were evaluated. The main conclusions are as follows: (1) underestimation of the precipitation by the two IMERG products tended to occur at higher hourly rainfall intensities (>2 mm at gauge scale and 100 mm at regional scale), while overestimation occurred at lower intensities. (2) The false-alarm rate (FAR) and RB values were significantly higher in the Pearl River Delta (PRD) than in other regions of the study area. (3) Through calculation of the TPC, a positive and negative offset phenomenon was identified over the region around Zhanjiang City in western Guangdong. By introducing the TPC for performance evaluation of IMERG products during Typhoon Cempaka, it was concluded that TPC is an advanced replacement of the RB for disclosing bias situations when adopting IMERG to monitor and reconstruct typhoon processes.

Analysis of Hydrochemical Characteristics and Causes of Drinking Water Sources in South China: A Case Study in Zhanjiang City

The evaluation of groundwater environmental quality and the identification of recharge sources are very important for groundwater utilization. In this study, hydrochemistry and isotope analysis methods are used to investigate the recharge sources and hydrochemical processes of groundwater in Zhanjiang City. The results show that all samples of groundwater were drawn on the left of the global meteoric water line (GMWL: δD = 8δ18O + 10) and local meteorological water lines (LMWL1: δD = 8.17δ18O + 11.74 and LMWL2: δD = 7.50δ18O + 6.18), indicating that the groundwater was mainly recharged by meteoric precipitation and influenced by the effect of evaporation. In the middle and deep confined aquifers, the isotope data depleted with the depth, indicating that there is a relatively weak hydraulic connection between them. In addition, compared with unconfined groundwater, the isotope data of confined groundwater showed relative depletion, indicating that the confined aquifer may be partially recharged from other confined aquifers. The main chemical types in the groundwater were Na*Ca-HCO3. There are three major natural hydrochemical processes controlling the source of groundwater ions: silicate weathering, carbonate dissolution, and the cation exchange reaction. In addition, the differences in physical and chemical properties between unconfined groundwater and confined groundwater are significant. Due to the differences in anthropogenic activities and land-use types, the nitrate of the unconfined groundwater exceeds the groundwater standards. Due to the geological background of Zhanjiang City, iron and manganese exceed the third standard of groundwater in confined groundwater. Due to groundwater exploitation, TDS levels in confined groundwater have been increasing. Closed groundwater extraction is not sustainable, and it is depleting ancient water reserves. This study highlights the effectiveness of hydrochemistry and isotope analysis methods for identifying the recharge area and recharge mode of groundwater, andit is significant for fully understanding groundwater hydrochemistry and scientifically managing and protecting groundwater.

Thermoluminescence of Natural Quartz Grains Beside Huguangyan Maar Lake

In order to study the relationship between the thermoluminescence (TL) properties of natural quartz crystals and the irradiation history, the TL test of quartz particles was carried out on volcanic ash near Huguangyan Maar Lake in Zhanjiang City. The TL glow curve and dose response of quartz were measured. The parameters of TL traps are calculated, and the activation energies corresponding to the TL peaks of 260, 310 and 365 °C of quartz grains are 1.34, 1.44 and 1.51eV, respectively. The peak position of the TL glow curve changes mildly with the increase of irradiation dose of quartz particles, indicating that the energy of a TL trap is not a single value, but an energy distribution; in the range of 355 °C to 375°C, the TL sensitivity changes greatly with the increase of the historical irradiation dose.

First Report of leaf spot disease caused by Enterobacter mori on Canna indica in China.

Canna indica L. is a popular landscape ornamental herb of family Cannaceae throughout China. This plant has been extensively cultivated for decoration and as an ornamental in China. C. indica was seriously affected by a disease in the garden in spring of 2021 with an incidence of 21.2 to 45.6%, and it caused economic loss to control plant diseases with chemicals. Both young and older leaves developed necrotic lesions with small water-soaked spots on leaves, which then enlarged and were bordered by chlorosis. Symptomatic tissues were collected from Zhanjiang city (21.2N110.3E) and Wuchuan city (21.4N110.7E) in Guangdong province. Three symptomatic leaves from each city were surface disinfected in a 1% hypochlorite solution for 3 mins followed by being rinsed in sterile distilled water for 3 times. Six bacterial isolates originated from six single colonies were recovered from the samples. Colonies were raised and opaque with smooth margins. The bacteria were gram-negative, rod-shaped with sizes ranged from 0.4-0.7 μm wide and 1.2-2.0 μm long, without endospore, and were facultative anaerobes. For molecular identification, the direct colony PCR method (Lu et al. 2012) was used to amplify the 16S rDNA (Moreno et al., 2002), gyrB, leuS and rpoB of 2 selected strains, EM21ZJ1 and EM21WC1 using the primer pairs 27F/1492R, gyrB3/gyrB4, leuS3 /leuS4 and rpoBjt112/ rpoBjt748 respectively (Deletoile et al., 2009). The resulting sequences were deposited in GenBank (ON600470 and ON600471 for 16S rDNA; ON600472 and ON600473 for gyrB; ON600474 and ON600475 for LeuS; ON600476 and ON600477 for rpoB). BLAST searches with the four gene sequences revealed the greatest similarity with the sequences of Enterobacter mori (Zhu et al. 2011). The available complete genome sequences of Enterobacter species, especially type strains, were downloaded and the sequences of the corresponding 4 genes of each genome was extracted by Bioedit software. The concatenated sequences were aligned by Mega 11.0 with the neighbor-joining method. Multilocus sequence typing analysis showed that the concatenated sequences of the 2 isolates were clustered with E. mori with 100% bootstrap value. The 2 isolates were selected for pathogenicity tests to fulfill Koch's postulates. Six plants at three- to five-leaf stage were inoculated with each isolate separately, 2 sites of each leaf were inoculated, one site was wounded with a sterile needle and the other was not. The 2 sites of each leaf were covered with a piece of cotton drenched with 200 µl bacteria suspension (108 CFU/ml) from 2 isolates separately. Control plants were inoculated identically except Luria-Bertani (LB) medium was used to drench the cotton. Inoculated plants were placed in an incubator at 25°C, and 80% humidity under a 12-h light/dark cycle for 7 days. After 3 days of incubation, water-soaked yellow spots were observed in all the inoculated plants in both wounded and unwounded sites, except the negative control. The water-soaked yellow spots enlarged and became necrotic that matched those seen in garden. The pathogenicity tests were conducted three times with similar results. The bacteria were then reisolated from the lesions and found to have the same colony morphology and 99.9% identity of 16S rDNA sequences as those of the inoculum. According to morphological and sequence analysis, the pathogen was identified as E. mori. To our knowledge, this is the first report of disease of C. indica caused by E. mori.

First report of 16SrII-V phytoplasma associated with cowpea (Vigna unguiculata) phyllody in China

Cowpea plants exhibiting virescence, phyllody and little leaf symptoms were observed in the fields of Zhanjiang City, Guangdong province of China in October 2020. Total DNA was extracted from symptomatic cowpea leaves. Using phytoplasma universal primer pairs (R16mF2/R16mR1, P1/P7) and a secA primer pair (secAfor1/secArev3), expected PCR fragments of approximately 1400, 1800 and 800 bp were amplified from all symptomatic cowpea leaves. MUSCLE analysis revealed that the representative 16S rRNA gene sequence of cowpea phyllody phytoplasma (CPP) shared 98.67% nucleotide identity with the reference strain WBDL of ‘Ca. Phytoplasma aurantifolia’ (GenBank accession number U15442); and 100% nucleotide identity with 16SrII-V phytoplasmas associated with ‘Praxelis clematidea’ phyllody (GenBank accession number KY568717); ‘Desmodium triflorum’ little leaf (GenBank accession number MT452308); and ‘Ixeris chinensis’, ‘Emilia sonchifolia’, and ‘Desmodium ovalifolium’ witches’ broom (GenBank accession number MT416114, MT420682 and MK956144, respectively). Phylogenetic analyses based on the 16S rRNA and secA gene sequences revealed that the CPP strain clustered with the 16SrII-V subgroup and 16SrII group, respectively. Virtual restriction fragment length polymorphism analysis of the 16S rRNA sequence revealed that CPP was associated with the 16SrII-V subgroup. To our knowledge, this is the first report of the16SrII-V subgroup of phytoplasmas associated with cowpea phyllody disease.

First report of Bougainvillea spectabilis Willd bacterial leaf spot caused by Pantoea stewartii subspecies indologenes in China.

Bougainvillea spectabilis Willd. is an important ornamental flowering plant belonging to the family Nyctaginaceae. It is widely used in landscape designs in tropical and subtropical regions. In December 2020, severe disease-causing leaf spots were discovered on the leaves of B. spectabilis in the Modern Agricultural Park (110°19' E, 21°26' N) Zhanjiang City, Guangdong Province, China. Field surveys revealed that the disease was widespread, with an incidence of 60-80%. Early symptoms on the leaves appeared as tiny leaf spots that later developed into concentric circles surrounded by a yellowish halo (Fig. 1). Diseased leaves with typical symptoms were collected for pathogen isolation. The leading edges of the lesions were excised, sanitized in 75% ethanol for 30 s and in 3% sodium hypochlorite for 3 min, and rinsed three times with sterile distilled water (SDW). The diseased tissue was crushed in 1 mL SDW, soaked for 15 min, and then spread onto nutrient agar medium on a petri dish. Circular, bright yellow colonies with smooth margins were observed after 24 h of incubation at 28 °C. The isolate (SJM1) was a gram-negative bacillus with positive results for catalase, indole synthesis, maltose, and arbutin and negative results for sorbitol, lactose, salicin, and starch hydrolysis. The SJM1 genomic DNA was extracted using the TIANamp Bacterial DNA Kit, and partial 16S rDNA gene segments were amplified using the bacterial generic primers 27F and 1492R. The collated 16S rDNA gene sequences were submitted to the NCBI GenBank (MZ723935). BLAST analysis of the sequences revealed 99.38% identity with Pantoea stewartii (MG517424.1). Amplification using subspecies-specific primers galE (#562/564; Gehring et al. 2014), glmS (#356/341; Wensing et al. 2010), and pstC + pstS (#338/339; Wensing et al. 2010) revealed that the genes showed 99-100% identity with P. stewartii subsp. indologenes (galE = 100%, MZ754494.1; glmS = 99.79%, MZ75496.1; and pstC + pstS = 99.89%, MZ754495.1). Phylogenetic trees were constructed using the neighbor-joining method (MEGA X), with both the 16S rDNA sequence (Fig. 2 2A) and the concatenated 16S rDNA, galE, pstC + pstS, and glmS sequences (Fig.2 2B). The SJM1 isolate belonged to the same clade as P. stewartii subsp. indologenes and was 99% homologous to P. stewartii subsp. indologenes strain ZJ-FGZX1 (Fig. 2 2B; Ren et al. 2020). Pathogenicity tests were performed through prick wound inoculation. Sterile needles were used to create fresh wounds on healthy young leaves of one-year-old B. spectabilis plants. Wounds were inoculated with 20 μl bacterial suspension (1 × 108 CFU/ml) or SDW. Four leaves per plant and three plants per treatment were evaluated. The plants were incubated at 28 °C temperature and 80-90% relative humidity. After 4-7 days of inoculation, all plants inoculated with the bacterial suspension had spot symptoms with a halo, similar to those observed in the field. However, leaves inoculated with SDW alone did not show any symptoms. Furthermore, the colony morphology and 16S rDNA sequences of the strains isolated from the inoculated leaves were identical to those of the original isolates. These results verified Koch's postulates. Based on biochemical identification and sequencing analysis, the pathogen causing B. spectabilis leaf spot was identified as P. stewartii subsp. indologenes. Previous reports have shown that P. stewartii subsp. indologenes can cause diseases in Dracaena sanderiana, Cenchrus americanus, and Allium cepa (Zhang et al. 2020, Ashajyothi et al. 2021, Stumpf et al. 2018). To our knowledge, this is the first report of P. stewartii subsp. indologenes causing B. spectabilis leaf spot disease in China.

Mental health status among non-medical college students returning to school during the COVID-19 pandemic in Zhanjiang city: A cross-sectional study.

The coronavirus disease-2019 (COVID-19) pandemic has brought huge and continuous damage to mental health. The mental health of non-medical college students after returning to school remains largely unknown and the influencing factors were awaited to be deciphered. This cross-sectional study was launched among 1,083 non-medical students in Zhanjiang city by means of online survey (WeChat App) from August 1st, 2022 to August 7th, 2022. Knowledge about COVID-19 and attitude toward COVID-19 were assessed by using 7-items and 5-items questionnaires, respectively. Sleep quality, anxiety and depression symptoms were evaluated by Pittsburgh sleep quality index (PSQI), Hamilton depression rating scale-17 (HDRS-17) and self-rating anxiety scale (SAS), respectively. The results showed that more than half of the participants were knowledgeable about COVID-19. The majority of the participants held positive attitude toward COVID-19. The data demonstrated that 6.8% students had poor sleep quality, and 1.86, 0.37 and 0.37% students had mild, moderate and severe anxiety, respectively. About 26.7, 4.7 and 1.7% students had minimal, mild-moderate and severe depression. Female students showed higher proportions of anxiety (p = 0.02) and depression (p < 0.0001) than male students. Students with monthly household income below 3,000 RMB were more vulnerable to anxiety (p = 0.017) and depression (p = 0.004). Correlation analysis and Multivariate logistic regression analysis results showed that lower grade was positively related with anxiety and depression. Female students, income lower than 3,000 RMB/month, poor knowledge about COVID-19 and negative attitude toward COVID-19 were associated with insomnia, anxiety and depression. This study indicated that during the COVID-19 pandemic, a majority of non-medical students returning to school remained good sleep quality and a small number of students suffered from depression and anxiety. To our knowledge, this is a novel study revealing the mental health of non-medical college students concerning COVID-19 in Zhanjiang.

Investigation on Macrofungi in Zhanjiang City

Investigation on Macrofungi in Zhanjiang City

Research on the Rural Geography Research Course in Senior High School Based on the PTBL Teaching Model—A Case Study of Zhanjiang City, Guangdong Province

Research on the Rural Geography Research Course in Senior High School Based on the PTBL Teaching Model—A Case Study of Zhanjiang City, Guangdong Province

Research on Professional Development of Rural Teachers in Zhanjiang City Based on SWOT-PEST Analysis

Under the background of rural revitalization strategy, the key of rural education revitalization lies in the construction of rural teachers, and the key of rural teacher team construction lies in the professional development of teachers. Based on the SWOT-PEST model, from the micro and macro perspective, combined with the current politics, economy, society, technology analyzes the internal advantages and disadvantages, and external opportunities and threats, which adheres to the principle of “play advantages, overcome disadvantages”, from strengthening school-based research, relying education informatization, building teacher education community, choosing the best and matching the school administrators putting forward the corresponding SO strategy, ST strategy, WO strategy and WT strategy.