RESUMEN

Wampee (Clausena lansium [Lour.] Skeels) is a tropical fruit. In July 2022, shoot rot symptom was observed in wampee (cv. JIXIN) in a field ((21°25'N, 110°10'E, about 100 ha ), Guangdong Province, China. The most obvious symptom of the disease was the rotting and withering of the tops. Disease incidence was approximately 90% (n = 500). Twenty diseased samples were randomly collected from the field and cut into 2 mm × 2 mm pieces next to the margins of diseased tissues. These pieces were then sterilized with 75% alcohol for 30 s and 2% sodium hypochlorite for 3 min and subsequently washed with sterile water three times. Tissue pieces were placed onto potato dextrose agar (PDA) and incubated at 25℃ for 3 days. Pure cultures were obtained by transferring hyphal tips to new PDA plates. Sixty isolates of Fusarium ssp. (60/80 = 75%) were obtained. Three representative single-spore isolates (CLFP-1, CLFP-2, and CLFP-3) were used for further study. Colonies were white to pink on PDA. Conidiogenous cells were monophialidic or polyphialidic. Macroconidia were slightly curved, tapering apically with 3 to 5 septa, and measured from 31.7 to 55.5 µm × 2.5 to 5.0 µm in size (n=50). The morphological features of these fungi were analogous to F. proliferatum (Leslie and Summerell 2006). For molecular identification, a colony PCR method (Lu et al. 2012) was used to amplify the internal transcribed spacer (ITS) and portions of elongation factor 1-α (EF1-α), RNA polymerase II largest subunit (RPB1), and RNA polymerase II second largest subunit (RPB2) genes using primers ITS1/ITS4, EF1-728F/EF1-986R, RPB1-R8/RPB1-F5, and RPB2-7CF/fRPB2-11aR, respectively (O'Donnell et al. 1998; 2010). The sequences were submitted to GenBank under accession numbers OP740961 to OP740963 (ITS), and OP800846 to OP800854 (RPB1, RPB2, EF1-α). The BLAST comparison of the sequences showed the three isolates were 100% similar to F. proliferatum (ITS: MT378328; TEF1: MH582344; RPB1: MN193921; RPB2: MN892349). The sequences of the three isolates were 100% identical (ITS, 537/537 bp; RPB1, 1606/1606 bp; RPB2, 770/770 bp and EF1-α, 683/683 bp) with those of F. proliferatum (accession nos. MT378328, MN193921, MH582196, and MH582344) through BLAST analysis. Analysis of the concatenated sequences revealed a 99.87 to 100% identity with the isolates of the F. proliferatum (F. fujikuroi species complex, Asian clade) by polyphasic identification using the FUSARIUM-ID database (Yilmaz et al. 2021). The sequences were also concatenated for phylogenetic analysis by the maximum likelihood method. The isolates clustered with F. proliferatum. Pathogenicity was tested through in vivo experiments. The inoculated and control plants (n = 5, 3 months old, cv. JIXIN) were sprayed with a spore suspension (1 × 105 per mL) of the three isolates and sterile distilled water, respectively, until run-off (Feng and Li. 2019). The test was performed three times. The plants were grown in pots in a greenhouse at 25℃ to 28℃, with relative humidity of approximately 80%. Symptoms were observed on the inoculated plants with disease incidence 100% after 2 weeks, while the control plants remained healthy. The pathogen re-isolated from all the inoculated plants was identical to the inoculated isolates in morphology and ITS sequences. No pathogen were isolated from the control plants. To the best of our knowledge, this study is the first to report F. proliferatum causing shoot blight symptom in wampee (cv. JIXIN). This disease has caused severe losses and will provide the foundation for management strategies.

RESUMEN

Twenty one riparian soil samples along Jiushanwai River and Shanxia River of Wenzhou city were collected in August 2010 to investigate the pollution characteristics of polycyclic aromatic hydrocarbons (PAHs). The samples were extracted by an accelerated solvent extractor (ASE), purified by a purification column and determined by GC-MS. Results showed that the total concentrations of PAHs in the riparian soils ranged from 60.7 ng x g(-1) to 3 871.3 ng x g(-1), and the concentrations of sigma PAHs in soils along the Shanxia River were significantly lower than the levels along Jiushanwai River. The dominant compounds were 2 to 3 rings in the riparian soils along both rivers, which in average accounted for 62.47% - 72.51% in sigma PAHs. Compared with the PAHs concentrations in soils of other areas in the world, the riparian soils of the studied rivers were moderately polluted by PAHs, but the concentrations of BaP in three soil samples were much higher than the soil standard value of the former Soviet Union, which should be paid more attention. Based on the ratios of Ant/(Ant + Phe) and Fla/(Fla + Pyr) and principal component analysis results, PAHs in riparian soils of the studied rivers were mainly derived from both the petroleum and combustion.

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RESUMEN

Concentrations of 18 polycyclic aromatic hydrocarbons (PAHs) in water and surface sediments collected from the urban rivers of Wenzhou city in spring and summer were measured by GC-MS. The results showed that the total PAHs concentrations in water and sediments of the studied rivers varied in ranges of 146.74-3 047.89 ng x L(-1) and 21.01-11 990.48 ng x g(-1), respectively. Higher concentrations occurred in spring. The low and middle rings of 2-4-ring were dominant in both water and sediments, but the concentrations of 5-ring and 6-ring PAHs in sediments were relatively higher than those in water. The EBaP values of PAHs in water of the studied rivers in spring and summer were 1.69-51.95 ng x L(-1) and 0-3.03 ng x L(-1), respectively. Eighty percent of water samples in spring surpassed the limits of BaP in surface water of China. The concentrations of sigma PAHs in the sediments both in spring and summer were lower than the ERM value, but part of the components of PAHs had values higher than the ERM, suggesting possible toxic effect on living organisms. Based on the PAHs molecule ratios and principal component analysis, a mixed PAHs source of petroleum and combustion in water and sediments was diagnosed, while sediments showed a greater proportion of combustion sources.

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The concentration and ecological risk of Polycyclic aromatic hydrocarbons (PAHs) were investigated in thirty-three surface soil samples collected from cultivated land in Chongming Island in July 2008. Those samples were extracted using an accelerated solvent extractor (ASE) and determined by GC-MS. Results showed that the concentrations of PAHs ranged between 24.92-1014.61 ng x g(-1) (dry weight), with a mean value of 192.83 ng x g(-1). The sixteen priority PAHs with exception of Indeno(1, 2, 3-cd) pyrene (IcdP) and Dibenzo(a, h)anthracene (DahA) were all detected in all the samples. The dominant compounds were 2-3 ring and 4 ring PAHs, which accounted for 42.6% and 42.2%, respectively, while the 5-6 ring PAHs accounted for 15.7%. PAHs in soil were mainly derived from the fossil oil and the combustion of wood and coal, as determined by the concentration ratio method. The non-industrial combustion and automobile exhaust emissions in Chongming Island may be two of the important sources of PAHs in farmland soil. The analysis of ecological risk showed that the agricultural soil of Chongming Island had low ecological risk.

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Thirty surface soil samples were collected to investigate the residue concentrations of organochlorine pesticides (OCPs) in agricultural soil of Chongming Island in July 2008. Those samples were extracted using accelerated solvent extraction (ASE) and determined by gas chromatography with an electron capture detector (GC-microECD). Results showed that the concentrations of OCPs (dry weight) ranged between 3.11-117.47 ng x g(-1), with mean value of 26.25 ng x g(-1). Two major contaminants of OCPs were DDTs and HCHs, the concentration of which varied from 0.14 ng x g(-1) to 77.89 ng x g(-1) and from 1.14 ng x g(-1) to 22.43 ng x g(-1), respectively. At the same times, hexachlorobenzene (0.23-11.63 ng x g(-1)), aldrin (0.03-0.75 ng x g(-1)), heptachlor epoxide (0.05-1.44 ng x g(-1)), dieldrin (0.05-5.33 ng x g(-1)), endrin (ND-14.66 ng x g(-1)) and mirex (0.03-10.58 ng x g(-1)) could also be detected. Most of DDTs had been degraded to DDD and DDE, with the major compounds of DDE (about 64.7%), and the recent existed DDT was the residue of early input. All of the four isomers of HCHs were detected, and the contents of alpha-HCH (about 48.1%) and beta-HCH (about 33.4%) were the maximum. The highest OCPs residues appeared in the soil of farm cultivation compared to greenhouse cultivation and ordinary open-air cultivation.

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