Lettuce (Lactuca sativa) is a leafy vegetable that belongs to the family Asteraceae. It is widely cultivated and consumed around the world. In May 2022, lettuce plants (cv. 204) showing soft rot symptoms were observed in greenhouses in Fuhai District (25°18'N, 103°6'E), Kunming City, Yunnan Province, China. The disease incidence in three greenhouses (0.3 ha in size) was between 10% to 15%. The lower parts of the outer leaves showed brown and water-soaked symptoms, but at the same time the roots were asymptomatic. Sclerotinia species can cause soft decay on lettuce leaves, known as lettuce drop, which can produce symptoms partially resembling those of bacterial soft rot (Subbarao 1998). The absence of white mycelium or black sclerotia on the leaf surfaces of diseased plants indicated that Sclerotinia species were not responsible for the disease. Instead, it is more likely that bacterial pathogens were the cause. Fourteen diseased plants were sampled from three greenhouses, and potential pathogens were isolated from the leaf tissues of six plant individuals. Leaf samples were cut into pieces ca. 0.5 cm in length. The pieces were then surface-sterilized by dipping in 75% ethanol for 60 sec, followed by three successive rinses using sterile distilled water. The tissues were immersed in 250 µl of 0.9% saline in 2 mL microcentrifuge tubes and gently pressed down with grinding pestles for 10 sec. The tubes were let stand still for 20 min. Aliquots (20 μl) 100-fold dilutions of the tissue suspensions were plated onto Luria-Bertani (LB) plates and incubated at 28°C for 24 h. Three single colonies were picked from each LB plate and restreaked five times for purity. After purification, eighteen strains were obtained, and nine of these were identified by 16S rDNA sequencing using the universal primer pair 27F/1492R (Weisburg et al. 1991). Six out of nine strains (6/9) belonged to the genus Pectobacterium (OP968950-OP968952, OQ568892- OQ568894), two strains (2/9) belonged to the genus Pantoea (OQ568895 and OQ568896), and one strain (1/9) belonged to Pseudomonas sp. (OQ568897). Since the Pectobacterium strains shared identical 16S rDNA sequence, strains CM22112 (OP968950), CM22113 (OP968951) and CM22132 (OP968952) were selected as representative strains for further testing. The 16S rDNA sequences of Pectobacterium strains were 100% identical to that of the P. polaris strain NIBIO 1392 (NR_159086.1). To identify the strains to the species level, multilocus sequence analysis (MLSA) was performed using sequences of six housekeeping genes acnA, gapA, icdA, mdh, proA and rpoS (OP972517-OP972534) (Ma et al. 2007; Waleron et al. 2008). Phylogenetic analysis showed that the strains clustered with P. polaris type strain NIBIO1006T (Dees et al. 2017). They were all capable of utilizing citrate, which is an important biochemical feature in distinguishing P. polaris from its most closely related sister species P. parvum (Pasanen et al. 2020). Lettuce plants (cv. 204), at the rosette stage, were inoculated with the strains CM22112 and CM22132 by injecting 100 µl of bacterial suspensions (107 CFU·mL-1) into the lower parts of the leaf; for the controls, 100 µl of saline was used instead. Inoculated plants were incubated at room temperature (23°C) and 90% relative humidity. Five days after inoculation, only the bacteria-inoculated lettuce showed severe soft rot symptoms. Similar results were observed in two independent experiments. Bacterial colonies were obtained from the infected lettuce leaves, which showed identical sequences to P. polaris strains CM22112 and CM22132. Therefore, these strains fulfilled Koch's postulates for lettuce soft rot. P. polaris is prevalent on potato in many countries (Dees et al. 2017). To our knowledge, this is the first report of P. polaris causing soft rot on lettuce in China. This disease could seriously affect the appearance and saleability of lettuce. Further research on the epidemiology and management strategies of the disease is needed.

从 10 个香菇菌株中筛选出 3 个不同菌龄适宜反季节栽培的菌株,分别为 0912(短菌龄)、808(中长菌龄)和 168(长菌龄),3 个菌株可搭配使用,其中菌株 0912 的经济价值最高.以菌株 0912 为例,在出菇管理期进行半针注水试验结果表明,与传统注水方式相比,半针注水明显降低了烂袋率,提升了优质菇率及生物学效率.

Pectobacterium brasiliense is a worldwide distributed bacterial pathogen causing soft rot and blackleg of a wide range of economically important crops. Here, we present the complete, high-quality genome of P. brasiliense strain TS20HJ1, which was isolated from a ginger ( Zingiber officinale) rhizome showing soft rot symptoms. The genome assembly consists of a circular 4,766,353-bp chromosome with 52.1% GC content. The genome harbors 4,128 protein-coding genes, 22 rRNA genes, and 77 tRNA genes. We believe that the complete genome sequence of P. brasiliense TS20HJ1 will provide a valuable resource for understanding the molecular basis of host adaptation and evolution of pathogenesis. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

芫荽,伞形科,又称香菜、香荽等,是做面煲汤常用的提味蔬菜之一[1,2].近几年大叶型香菜品种作为涮菜广受欢迎,需求量不断增加[3].芫荽生长期短,耐低温,适合冷凉气候地区种植[4].冀东地区种植秋季露地芫荽多年,通过冬储供给京津冀和东北地区冬春市场.近年冷库凭借温度稳定、存储损耗小、省时省工的特点逐渐取代了传统的埋土法,储藏方式升级大幅提高了经济效益,助推生产规模不断扩大.但冀东地区特殊的气候条件,加之连年重茬种植造成芫荽容易出现徒长、红叶和重茬病害3方面问题,围绕本地芫荽生产中的实际问题,总结了 3项冀东地区秋季露地芫荽栽培关键技术,有效地控制了病虫害的发生,避免了株高超标或红叶造成的产量和品质下降,增加了菜农收入.该技术通过多年的集成熟化、示范应用,在唐山地区累计推广超过0.67万hm2,具有良好的应用前景,希望这3项关键技术可以为其他芫荽产区提供技术支持.

HomePlant DiseaseVol. 106, No. 7First Report of Rhizome Rot Caused by Pectobacterium brasiliense on Ginger in China PreviousNext DISEASE NOTE OPENOpen Access licenseFirst Report of Rhizome Rot Caused by Pectobacterium brasiliense on Ginger in ChinaJinhui Wang, Yuxiang Lu, Wanxin Han, Lijun Fu, Xiaoqing Han, Jiehua Zhu, and Shangqing ZhangJinhui Wanghttps://orcid.org/0000-0002-4328-984XHebei Agricultural University, College of Plant Protection, Baoding 071001, China, Yuxiang LuTangshan Academy of Agricultural Sciences, Tangshan 063001, China, Wanxin Hanhttps://orcid.org/0000-0002-6037-8027Hebei Agricultural University, College of Plant Protection, Baoding 071001, China, Lijun FuTangshan Academy of Agricultural Sciences, Tangshan 063001, China, Xiaoqing HanTangshan Academy of Agricultural Sciences, Tangshan 063001, China, Jiehua Zhu†Corresponding authors: J. Zhu; E-mail Address: [email protected], and S. Zhang; E-mail Address: [email protected]Hebei Agricultural University, College of Plant Protection, Baoding 071001, China, and Shangqing Zhang†Corresponding authors: J. Zhu; E-mail Address: [email protected], and S. Zhang; E-mail Address: [email protected]Tangshan Academy of Agricultural Sciences, Tangshan 063001, ChinaAffiliationsAuthors and Affiliations Jinhui Wang1 Yuxiang Lu2 Wanxin Han1 Lijun Fu2 Xiaoqing Han2 Jiehua Zhu1 † Shangqing Zhang2 † 1Hebei Agricultural University, College of Plant Protection, Baoding 071001, China 2Tangshan Academy of Agricultural Sciences, Tangshan 063001, China Published Online:16 Jun 2022https://doi.org/10.1094/PDIS-10-21-2324-PDNAboutSectionsView articlePDFSupplemental ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmailWechat View articleIn August 2020, ginger (Zingiber officinale) rhizomes (cv. Mianjiang) showing soft rot symptoms were observed in a field in Tayang Village, Fengrun District, Tangshan, Hebei Province (North China). The disease incidence in that field (15 ha in size) was more than 20%. Symptomatic rhizomes (brown and water-soaked) were surface-sterilized in 75% ethanol for 60 s, followed by three successive rinses with sterile distilled water. Rhizomes were cut into pieces ca. 0.5 cm in length that were soaked in 500 µl of 0.9% saline for 20 min. Aliquots (20 μl) of three tenfold dilutions of the tissue specimen soaking solution were plated onto lysogeny broth (LB) medium and incubated at 28°C for 24 h. Five single colonies were picked from each LB plate and restreaked three times for purity. Endophytic bacteria were also isolated from asymptomatic rhizomes as a control. The bacterial gDNA was extracted using the EasyPure Bacteria Genomic DNA Kit (TransGen Biotech, Beijing, China). The 16S rDNA region was amplified by PCR using the universal primer pair 27F/1492R (Weisburg et al. 1991) and sequenced. The results of BLASTn against NCBI nr of the 16S rDNA amplicons suggested that most isolates (8/10) obtained from the rotten rhizomes belonged to the genus Pectobacterium, and a few isolates (2/10) were Enterobacter spp. Only Enterobacter spp. were isolated from asymptomatic rhizomes. Since all Pectobacterium isolates showed identical 16S rDNA sequences, only two isolates were selected for further analysis. Pectobacterium isolates TS20HJ1 and TS20HJ2 (MZ853520, MZ853521) represent isolates from two plant individuals. To determine the species of the rhizome rot Pectobacterium isolates, multilocus sequence analysis (MLSA) was performed with five housekeeping genes: acnA, icdA, mdh, proA, and rpoS (MZ994717 to MZ994726) (Ma et al. 2007; Waleron et al. 2008), and a phylogenetic tree was reconstructed using RAxML v8.2.12 (github.com/stamatak/standard-RAxML). No sequence variation was observed at any MLSA locus between the two isolates. The results of phylogenetic analysis showed that the ginger rhizome isolates clustered with Pectobacterium brasiliense type strain IBSBF1692T (Duarte et al. 2004; Nabhan et al. 2012). Ginger seedlings (cv. Mianjiang) were inoculated with the isolate TS20HJ1 by injecting 10 µl of bacterial suspension (108 CFU·ml−1) into the rhizomes or 10 µl of 0.9% saline solution as a control. The seedlings were grown at 28°C and 50% relative humidity. Ten days after inoculation, only the bacteria-inoculated rhizomes showed disease symptoms resembling those observed in the field. Bacterial colonies were obtained from the infected rhizomes and were identified with MLSA gene sequencing, fulfilling Koch's postulates. P. brasiliense causes soft rot of a wide range of economically important crops (Oulghazi et al. 2021). To our knowledge, this is the first report of P. brasiliense causing rhizome rot of ginger in China. The rhizome rot caused 20 to 25% yield loss on average in the Tangshan region in 2020, which poses a significant threat to local ginger farming. Further research on epidemiology and disease management options is needed.The author(s) declare no conflict of interest.References:Duarte, V., et al. 2004. J. Appl. Microbiol. 96:535. https://doi.org/10.1111/j.1365-2672.2004.02173.x Crossref, ISI, Google ScholarMa, B., et al. 2007. Phytopathology 97:1150. https://doi.org/10.1094/PHYTO-97-9-1150 Link, ISI, Google ScholarNabhan, S., et al. 2012. J. Appl. Microbiol. 113:904. https://doi.org/10.1111/j.1365-2672.2012.05383.x Crossref, ISI, Google ScholarOulghazi, S., et al. 2021. Microorganisms 9:106. https://doi.org/10.3390/microorganisms9010106 Crossref, Google ScholarWaleron, M., et al. 2008. Eur. J. Plant Pathol. 121:161. https://doi.org/10.1007/s10658-007-9260-3 Crossref, ISI, Google ScholarWeisburg, W. G., et al. 1991. J. Bacteriol. 173:697. https://doi.org/10.1128/jb.173.2.697-703.1991 Crossref, ISI, Google ScholarJ. Wang and Y. Lu contributed equally to this work.Funding: This research work was supported by the Agriculture and Rural Affairs Support Program of Hebei (HBCT-2018-030207) and High-level Talent Funding Project of Hebei (A202001094).The author(s) declare no conflict of interest.DetailsFiguresLiterature CitedRelated Vol. 106, No. 7 July 2022SubscribeISSN:0191-2917e-ISSN:1943-7692 Download Metrics Article History Issue Date: 8 Jul 2022Published: 16 Jun 2022First Look: 16 Jan 2022Accepted: 10 Jan 2022 Page: 1978 Information© 2022 The American Phytopathological SocietyFundingAgriculture and Rural Affairs Support Program of HebeiGrant/Award Number: HBCT-2018-030207High-level Talent Funding Project of HebeiGrant/Award Number: A202001094KeywordsgingerMLSArhizome rotThe author(s) declare no conflict of interest.PDF download

为了提高吡噻菌胺对黄瓜白粉病的防治效果,筛选增效配方,降低抗性风险,为其应用提供理论依据.采用常规喷雾法进行田间防效试验.田间试验结果表明,20％吡噻菌胺SC+10％多抗霉素WP对黄瓜白粉病防效突出,第1次药后7 d防效为84.39％,第2次药后14 d防效高达97.48％.20％吡噻菌胺SC+10％多抗霉素WP增效作用明显,可以在黄瓜生产中推广应用.20％吡噻菌胺SC+30％苯甲·嘧菌酯SC对黄瓜白粉病也有较好的增效作用,可降低抗性风险,作为备选或轮换使用的方案.

草莓,原产南美洲,多年生草本植物.其品种资源丰富,口感酸甜各异,气味香甜浓郁,深受广大消费者喜爱.草莓喜低温冷凉气候,对设施条件要求不高,且植株低矮,便于休闲采摘,市场需求量大,收益较高,已逐步成为北方地区城市周边观光农业生产的首选品种.采摘种植的品种主要包括红颜、章姬、圣诞红、小白、雪兔、白雪公主、京藏香、粉红公主等,这些品种大多风味独特、颜色诱人,但果皮较薄、果实偏软,抗病能力不足,同时冬春季节日光温室内长期低温弱光、高湿,为病害的发生提供了条件,此外,观光采摘过程中,儿童因缺乏采摘经验易对秧苗和未成熟果实造成损伤,病菌会从伤口侵入,导致灰霉病大规模发生流行.