Small RNA deep sequencing reveals the presence of multiple viral infections in cucurbit crops in Guangdong,China

Viral diseases are among the most critical damaging factors that impose a global threat to the cucurbit industry. China is the world's leading country for the production and consumption of cucurbits. Guangdong, a province in southern China dominated by the tropical and subtropical climate, favors the survival of different plant viruses and their vectors. Five main cucurbit crops showing various disease symptoms were surveyed and collected to identify viruses infecting cucurbits in Guangdong during 2018–2020. In the field, the incidence ranged from 5–30%, or even 60–100% in the case of severely infected cucurbits. A total of 357 symptomatic samples were collected and subsequently screened for cucurbit viruses by small RNA deep sequencing and assembly (sRSA). Seventeen virus species belonging to 10 genera were identified in the five main cucurbit crops. The most common viruses were papaya ringspot virus (PRSV; Potyvirus), zucchini tigre mosaic virus (ZTMV; Potyvirus), zucchini yellow mosaic virus (ZYMV; Potyvirus), and watermelon silver mottle virus (WSMoV; Orthotospovirus), with infection rates of 24.4, 19.0, 17.1, and 14.3%, respectively. Notably, the most prevalent viruses were melon yellow spot orthotospovirus (MYSV) in cucumber, PRSV in squash, cucumber green mottle mosaic virus (CGMMV; Tobamovirus) in bottle gourd, WSMoV in white gourd, and ZYMV in luffa. Mixed infections were prevalent, and the types of mixed infections varied substantially in different cucurbit crops. Moreover, the full-length nucleotide sequences of watermelon green mottle mosaic virus (WGMMV), CGMMV, and watermelon virus A (WVA; Wamavirus) identified in bottle gourd were cloned and analyzed. This study is the first reporting WGMMV infecting bottle gourd in China mainland. In summary, the results demonstrate that in Guangdong, the most prevalent viruses belong to potyviruses, orthotospoviruses, and tobamoviruses groups. The findings will facilitate agricultural researchers and farmers to plan and implement effective disease control strategies aiming at timely detection and management of cucurbit-infecting viral pathogens.     

蚜虫与蔬菜病毒流行的关系及阻断蚜虫传毒的途径

 在田间多数蔬菜病毒都以蚜虫为媒介进行传播,蚜虫与蔬菜病毒流行关系密切,了解这些关系对有效防治蚜传蔬菜病毒病有重要意义。为此,本文综述了蔬菜上主要蚜传病毒及传毒蚜虫种类;蚜虫传播蔬菜病毒病的特点;有翅蚜迁飞与蔬菜病毒流行的关系及阻断蚜虫传毒的途径等问题。     

A preliminary survey of viruses in pasture grasses in South Africa

Little work has been done in South Africa on the incidence of viruses in pasture grasses. The aim of this work was to carry out a survey of virus infections of some of the economically‐important pasture grasses in South Africa. Twelve winter and summer pasture grass species and one cereal forage crop species were collected from six different regions in early, mid‐ and late winter and summer. Plants were tested for virus(es) by means of symptomatology, transmission, dot‐blot immunoassays, Ouchterlony tests and electron microscopy. Serological tests indicate that Avena sativa from Roodeplaat and Bromus unioloides from Potchefstroom, Cedara and Nooitgedacht are positive for maize dwarf mosaic virus (MDMV). Lolium multiflorum from Cedara appears to be infected with two viruses, brome mosaic virus (BMV) and a potyvirus‐like agent, possibly ryegrass mosaic virus (RMV).     

免疫胶体金技术在马铃薯病毒检测上的应用

免疫胶体金技术是一种快速、简便、结果容易判定的新型免疫标记技术,应用免疫胶体金技术制备试纸条具有特异性强、价格低、灵敏度高的特点,适用于马铃薯病毒检测,特别广泛适用于田间和口岸现场检测等工作。文章对免疫胶体金技术的基本原理、制备方法以及其目前在马铃薯病毒检测中的应用情况进行了综述。     

应用多重RT-PCR检测甘蔗黄叶病毒和高梁花叶病毒

建立了多重RT-PCR同时检测甘蔗黄叶病毒(Sugarcane yellow leaf virus,ScYLV)和高梁花叶病毒病毒(Sorghum mosaic virus,SrMV)的技术体系,该体系可有效地对甘蔗田间植株和试管苗进行检测.根据引物之问的互补性及引物的Tm值筛选多重PCR引物.确定适宜的PCR缓冲液的...     

连翘酯苷药理活性研究进展

连翘酯苷作为中草药连翘中一个主要的有效成分,具有广泛的药理学活性。连翘酯苷不仅能抑制引起感染的各种革兰氏阳性菌和阴性菌,而且还具有较强的抗病毒作用。连翘酯苷通过调控各种细胞因子,发挥免疫调节作用,同时通过清除体内的自由基,发挥抗氧化作用。作者针对连翘酯苷药理学活性进行了综述。     

不同亚群禽白血病病毒5'LTR序列及启动子活性分析

对不同亚群禽白血病病毒(avian leukosis virus,ALV) 5'LTR序列及其启动子活性进行了比较分析,以探讨LTR对ALV复制和致病力的影响。通过PCR分别扩增克隆了中国分离株GD08(ALV-A)、CD08(ALV-B)、HN06(血管瘤病变型ALV-J)和NX0101(骨髓瘤病变型ALV-J)毒株基因组5'LTR片段。与国内外不同亚群ALV分离株5'LTR核苷酸序列比较发现,NX0101株和HN06株与ALV-J国内外分离株的同源性最高,达90.8％~97.5％;GD08株与ALV-A国内分离株SDAU09C1的同源性最高,为94.6％;CD08株与GD08株和ALV-J各株的同源性高达90％以上。LTR中的R区具有较高的保守性,但CD08株U3区缺失11 bp,GD08株U5区与其它毒株的U5区差异较大。将LTR片段插入到pCAT-Basic载体的CAT报告基因前,通过转染DF-1细胞和测定CAT表达量来评价LTR的启动子活性。HN06株和NX0101株之间,以及GD08株和CD08株之间LTR启动子活性有差异,但差异不显著;而ALV-J毒株与GD08株和CD08株之间的LTR启动子活性差异显著。     

应用多重SYBR Green-I实时荧光定量PCR检测甘蔗黄叶病毒和高粱花叶病毒

基于已报道的甘蔗黄叶病毒(Sugarcane Yellow Leaf Virus,ScYLV)cp基因和高粱花叶病毒(Sorghum mosaic virus,SrMV)NSP基因序列设计特异性引物,建立了针对这两种病毒的实时荧光定量 PCR(real time-quantitative,RT-qPCR）检测方法。在此基础上,利用扩增产物Tm值的不同,建立了可区分ScYLV与SrMV的多重 SYBR Green-I实时荧光定量PCR方法,两种病毒扩增产物的Tm值分别为80.8～82.8℃和84.6～86.     

应用多重SYBR Green—I实时荧光定量PCR检测甘蔗黄叶病毒和高梁花叶病毒

基于已报道的甘蔗黄叶病毒（SugarcaneYellowLeafVirus．SCYLV）cp基因和高粱花叶病毒（Sorghummosaicvirus．SrMV）NSP基因序列设计特异性引物．建立了针对这两种病毒的实时荧光定量PCR（re矗time-quantitative,RT-qPCR）检测方法。在此基础上,利用扩增产物‰值的不同,建立了可区分ScYLV与SrMV的多重SYBRGreen—I实时荧光定量PCR方法．两种病毒扩增产物的‰值分别为80．8～82．8℃和84．6～86．6℃。检测数据显示：SrMV和ScYLV均有各自的特异性峰值出现,而健康植株无特异性峰值;在单独检测中的检出水平分别可达500和250copy／ixL：两种病毒m值的批内变异系数分别为0．03％和0．0270．批间变异系数分别为2．0670和3．1270。综上所述．所建立的多重SYBRGreen—I实时荧光定量PCR方法在对以上两种病毒的检测中具有较好的特异性、敏感性和稳定性。