蚕豆萎蔫病毒单克隆抗体制备及检测应用

:用蚕豆萎蔫病毒(BBWV)免疫的BALB/C鼠脾细胞与SP2/0鼠骨髓瘤细胞融合,经筛选克隆,获得6株能稳定传代并分泌抗BBWV单克隆抗体(Mab)的杂交瘤细胞株,单抗腹水ELISA滴度为1:320000～1:640000,各单抗抗体类型均为IgG1。6株单抗与BBWV不同分离物均有反应,而与其它植物病毒无交叉反应。经Westernblot印迹分析表明,此6株单克隆抗体均是针对BBWV447kD的外壳蛋白大亚基的特异性抗体。这是国内外首次报道获得BBWV单克隆抗体     

The influence of temperature and precipitation on spring dispersal of Frankliniella fusca changes as the season progresses

Effects of temperature and precipitation on spring dispersal patterns of Frankliniella fusca (Hinds) (Thysanoptera: Thripidae) caught on yellow sticky traps were estimated in central and eastern North Carolina and eastern Virginia, USA, from 1997 to 2001, and in 2004 and 2007. Data were collected from 44 sites within 14 locations over 7 years, resulting in 30 location‐year data combinations. The following independent variables were examined to determine their relationship to the number of F. fusca caught on sticky traps during specified time intervals: cumulative degree days (base 10.5 °C) from 1 November to the start of each trapping interval (DD), number of days with temperatures favorable for flight during each trapping interval (DTFF), and an index of rainfall during specific intervals prior to and during the trapping interval (RI). Regression models that contained various combinations of these variables explained 62, 79, 74, and 68% of the variation in the number of dispersing F. fusca captured during 1–15 April, 16–30 April, 1–15 May, and 16–31 May, respectively. The results provide strong evidence that the suppressive effects of precipitation on growth of local populations developing during late winter and early spring are subsequently manifest at the landscape scale as reductions in the populations of dispersing adults that may persist for as long as 5–6 weeks after the precipitation occurs.     

间作缓解蚕豆连作障碍的根际微生态效应

通过田间小区试验,研究了3个品种蚕豆(92-24、云豆324、凤豆6号)与小麦间作对蚕豆产量、枯萎病病情指数、根际镰刀菌数量、根际真菌代谢功能多样性和土壤酶活性的影响。结果表明:与单作蚕豆相比,云豆324与小麦间作(YD324/W)和凤豆6号与小麦间作(FD6/W)处理均显著提高了蚕豆地上部干重、籽粒产量和百粒重。YD324/W和FD6/W处理使蚕豆枯萎病发病初期病情指数分别降低57.14%和41.67%,镰刀菌数量分别降低32.06%和29.88%,而92-24与小麦间作(92-24/W)处理蚕豆产量、枯萎病病情指数和镰刀菌数量与单作蚕豆均无显著差异。YD324/W和FD6/W处理显著提高了蚕豆根际真菌的多样性指数和丰富度指数,并使蚕豆根际真菌的AWCD值分别比单作蚕豆提高了61.75%和46.49%;YD324/W和FD6/W处理明显改变了蚕豆根际真菌的群落结构。而92-24/W处理对蚕豆根际真菌的多样性指数、丰富度指数和AWCD值均无显著影响,也未明显改变真菌的群落结构。不同发病时期,YD324/W和FD6/W处理均显著提高了蚕豆根际土壤的蔗糖酶、脲酶和过氧化氢酶活性;而92-24/W处理蚕豆根际蔗糖酶、脲酶和过氧化氢酶活性与单作蚕豆均无显著差异。总之,小麦与不同品种蚕豆间作改变了蚕豆根际的真菌群落结构,提高了蚕豆根际真菌的活性、多样性和丰富度,提高土壤酶活性并改善蚕豆生长,增加了蚕豆产量。表明小麦与蚕豆间作改善了根际土壤的微生态环境,降低了镰刀菌的数量,缓解了蚕豆连作障碍,但蚕豆品种的差异影响间作控病效果。     

酚酸物质对黄瓜幼苗及枯萎病菌菌丝生长的影响

研究了不同连作年限大棚土壤中酚酸物质的种类、含量及其对黄瓜幼苗和枯萎病菌菌丝生长的影响。结果表明:土壤中香草酸、对羟基苯甲酸及阿魏酸随黄瓜连作年限增加而呈现积累趋势;在连作7年的大棚土壤中3种酚酸类物质总量达29.8mg.kg-1干土,显著高于连作1年和3年土壤中的含量;酚酸物质可使黄瓜幼苗根长及茎粗显著降低,使株高及干物质量略有下降。与对照相比,酚酸物质使黄瓜幼苗体内过氧化物酶(POD)活性在短期内升高,5d后又呈下降趋势;对超氧化物歧化酶(SOD)活性的影响也表现出先升高后下降的变化趋势。高浓度酚酸使黄瓜幼苗丙二醛(MDA)含量持续升高。枯萎病菌菌丝生长测定表明:42h内,低浓度(≤50mg.L-1)酚酸对枯萎病菌丝生长有刺激作用;酚酸浓度高于50mg.L-1时,对菌丝生长有抑制作用;随酚酸处理时间延长,枯萎病菌对酚酸物质的耐受性增强,对高浓度酚酸的生长抑制作用表现不明显。     

First Report of Curtobacterium flaccumfaciens pv. flaccumfaciens Causing Cowpea Bacterial Wilt in Iran

During surveys in cowpea fields of Marand County, East Azerbaijan province, Iran, in the summer of 2013, a suspected bacterial disease was observed on cowpea leaves as tan spots and interveinal necrotic lesions surrounded by chlorotic margins. The disease was of high incidence where some fields had been fully destroyed and severity of the disease in some fields had reached up to 70%. Gram‐positive, yellow‐pigmented, coryneform bacteria were isolated from infected leaves. Pathogenicity of isolates was confirmed on 20‐day‐old cowpea (cv. Khoy) plants, and they were identified as Curtobacterium flaccumfaciens pv. flaccumfaciens based on biochemical test results confirmed using specific PCR primers. This is the first report of C. flaccumfaciens pv. flaccumfaciens, the causal agent of cowpea bacterial wilt in Iran.     

对枯萎病不同抗性的香蕉品种的内生细菌多样性及群落结构

【目的】了解抗感品种香蕉植株中内生细菌与香蕉枯萎病间的关系,从而为香蕉枯萎病的发生与防控提供一定的理论基础。【方法】通过基于16S rRNA的末端标记限制性片段长度多态性技术(Terminal restriction fragment length polymorphism,T-RFLP)分析健康和感枯萎病香蕉植株不同品种各组织,以及香蕉植株不同发病时间根组织中内生细菌的多样性和群落结构。【结果】抗病品种"农科一号"植株根、假茎、叶片各组织中内生细菌的种类基本都比感病品种"巴西蕉"的相应组织中的要丰富。感枯萎病香蕉植株根、假茎、叶片各组织中内生细菌种类基本都比健康植株各组织的丰富。在植株发病前、发病初期、再到发病后一个月的不同时期,对于抗病品种而言,其内生细菌的多样性都基本保持稳定,而感病品种则变化幅度较大。同时发现不同品种不同组织的内生细菌的优势种群有所不同,且不同品种健康和发病植株都存在一些特有优势种群。【结论】香蕉抗病品种比感病品种植株中内生细菌的多样性更丰富且更稳定;感枯萎病植株中的内生细菌种类比健康的丰富;而且不同抗性品种中健康和感病植株内的优势种群存在明显差异。     

接种番茄斑萎病毒番茄植株对西花蓟马生物学特性的影响

西花蓟马Frankliniella occidentalis(Pergande)是我国的一种重要入侵害虫。本文研究了西花蓟马在番茄3种处理(健康CK、机械接种番茄斑萎病毒MI、机械损伤MD)叶片上的生长发育、存活及种群增长。结果表明:健康、机械接种番茄斑萎病毒、机械损伤叶片上的发育历期依次为12.68、12.99和11.79d。雌雄成虫寿命和雌虫繁殖能力在各处理叶片上差异不显著(P>0.05)。健康、机械接种番茄斑萎病毒、机械损伤叶片上的内禀增长率依次为0.1362、0.1526和0.1292d-1。本研究表明,接种番茄斑萎病毒的番茄叶片未缩短西花蓟马发育历期,也不能延长寿命及提高产卵量,不能明显加速种群数量增长。这意味着番茄斑萎病毒对西花蓟马在番茄叶片上的生物学特性未能产生明显的有利作用。     

XSP10 and SlSAMT,Fusarium wilt disease responsive genes of tomato (Solanum lycopersicum L.) express tissue specifically and interact with each other at cytoplasm in vivo

Fusarium wilt caused by Fusarium oxysporum f. sp. lycopersici (Fol) is a major fungal disease of tomato (Solanum lycopersicum L.). Xylem sap protein 10 (XSP10) and Salicylic acid methyl transferase (SlSAMT) have been identified as putative negative regulatory genes associated with Fusarium wilt of tomato. Despite their importance as potential genes for developing Fusarium wilt disease tolerance, very little knowledge is available about their expression, cell biology, and functional genomics. Semi-quantitative and quantitative real-time PCR expression analysis of XSP10 and SlSAMT, in this study, revealed higher expression in root and flower tissue respectively in different tomato cultivars viz. Micro-Tom (MT), Arka Vikas (AV), and Arka Abhed (AA). Therefore, the highly up-regulated expression of XSP10 and SlSAMT in biotic stress susceptible tomato cultivar (AV) than a multiple disease resistant cultivar (AA) suggested the disease susceptibility nature of these genes for Fusarium wilt. Sub-cellular localization analysis through the expression of gateway cloning constructs in tomato protoplasts and seedlings showed the predominant localization of XSP10 in the nucleus and SlSAMT at the cytoplasm. A strong in vivo protein–protein interaction of XSP10 with SlSAMT at cytoplasm from bi-molecular fluorescent complementation study suggested that these two proteins function together in regulating responses to Fusarium wilt tolerance in tomato.Supplementary InformationThe online version contains supplementary material available at 10.1007/s12298-021-01025-y.     

Herbivore arthropods benefit from vectoring plant viruses

Plants infected with pathogens often attract the pathogens’ vectors, but it is not clear if this is advantageous to the vectors. We therefore quantified the direct and indirect (through the host plant) effects of a pathogen on its vector. A positive direct effect of the plant‐pathogenic Tomato spotted wilt virus on its thrips vector (Frankliniella occidentalis) was found, but the main effect was indirect; juvenile survival and developmental rate of thrips was lower on pepper plants that were damaged by virus‐free thrips than on unattacked plants, but such negative effects were absent on plants that were damaged and inoculated by infected thrips or were mechanically inoculated with the virus. Hence, potential vectors benefit from attacking plants with virus because virus‐infected plants are of higher quality for the vector's offspring. We propose that plant pathogens in general have evolved mechanisms to overcome plant defences against their vectors, thus promoting pathogen spread.     

Seeds as Vehicles for Pathogen Importation

Since the 1900s, consumer demand for new plant products gave opportunity for many plant pathogens to disseminate to new areas on imported seeds. New markets for plant commodities encouraged plant breeders to begin collecting seed stocks from abroad. The birth of new seed companies extend their markets to new area. These events began the global dissemination of many seedborne pathogens. Many seedborne pathogens gained entry and escaped detection by specific traits that favored their dissemination. Three recent case scenarios are presented that illustrate how plant pathogens that passively employ the seed coats of their host achieved global dissemination and permanence in each patho-system. Evidence is presented to show that asparagus (Asparagus officinalis) seed produced in the US acted as a vehicle for disseminating one vegetatively compatible group (VCG) of a pathogenic fungus on asparagus called Fusarium proliferatum throughout new plantings in Australia. Similarly, public demand for Mediterranean cuisine in the US and abroad during the last 20 years led to an increase in the importation of basil (Ocimum basilicum) seed along with an inconspicuous fungus called Fusarium oxysporum. The fungus caused a destructive disease called Fusarium wilt of basil that appeared in over 25 separate locals spanning three continents. The third example demonstrated how new developments in lupine (Lupinus spp.) cultivars and increased public demand led to the global dispersal of a seedborne pathogen called Colletotrichum gloeosporioides. Each case highlights how these pathogens use seeds, humans, and particular traits to disperse globally in short period of time.