菟丝子传递甘薯丛枝病研究初报

 1983~1984年,以紫红色长春花(Vinca rosea)为指示植物进行欧洲菟丝子(Cuscuta australis)传递甘薯丛枝病试验,并采用电子显微镜和超薄切片技术比较甘薯丛枝病原(MLOs)在罹病长春花和甘薯组织内的形态和密度。电镜观察结果表明:除长春花健株样本切片未发现任何类似菌原体的构造外,在甘薯和长春花病株的样本切片上均发现类菌原体。     

玉米粗缩病发生严重

近年来我县玉米粗缩病(Maize roughdwarf virus)严重。1992年夏玉米发病7万亩,其中以套种玉米发生最重。一般病株率2.5％,严重地块病株占30.7％;直播夏玉米发病株率为0.5％,最高5％。发病程度在品种间差异很大,以改良掖单2号(新2号)最重,平均夏套种的病株率为15％,发病最重的病株率占48％。1993年5月,春玉米田也已发现病株。玉米粗缩病在苗期叶色深,生长健壮,与健苗高度一样,间苗时往往误留,玉米拔节期植株开始矮化,叶色黑绿,茎秆粗壮,     

木麻黄丛枝病过氧化物酶同工酶的初步研究

 利用聚丙烯酰胺凝胶电泳研究了木麻黄丛枝病健、病株以及各病级间过氧化物酶同工酶的变化.测定的结果,健株的过氧化物酶同工酶的活性比病株的要强;酶带数多2-6条.病级间过氧化物酶同工酶的变化与植株外部表现的症状相反,即病情越重,酶活性和带数则越小.因此植株的同工酶变化可看作植株内部的"生化症状",并可用作木麻黄丛枝病、健以及发病程度的简单而有效的鉴定方法.     

组织化学技术快速检测泡桐丛枝病研究

 迪纳氏染色和萤光显微镜技术——苯胺蓝染色法,和DAPI染色法,可从感染泡桐丛枝病的嫩茎和叶柄及将MLO转接到长春花上,表现典型症状的嫩茎和叶柄中诊断MLO的侵染。病株切片的迪纳氏染色阳性,健株切片阴性。苯胺蓝染色病株韧皮部产生的特异性萤光区域比健株大。DAPI染色可直接检测韧皮部组织中的MLO,而且韧皮部萤光强度与MLO的密度和外部症状严重度呈正相关。三种染色方法比较结果说明,DAPI染色法是一种灵敏度高,特异性更强的泡桐丛枝病类菌原体检测方法。     

电流处理抑制甘薯丛枝病症状及提高茎尖培养成苗率

甘薯丛枝病在我国东南沿海主薯区流行多年,发病率高,是影响我国甘薯产量和品质的一个主要限制因子。其典型症状是植株叶小、褪绿、矮缩和侧枝丛生。甘薯丛枝病病原物是一种类菌质体(Mycoplasma-like organism,MLO),现在国际上统称植原体(Phytoplasma)。     

甘薯不同品种(系)对根腐病抗性鉴定研究

甘薯根腐病（Fusariumsolani(Mart)f.sp．batatasMcclurc．）是江西省甘薯上新发生的一种病害。1979年在新建县昌邑乡发现零里病株，1983年发病面积达1000多市。甘薯感病后，重病株提前枯死，造成缺株垄断；轻病株能继续生长，地下部根茎产生黑色病斑，多数结成柴根，有的虽结成薯块，但长不大，呈畸形，表面产生许多黑色园形病斑，严重影响甘薯产量与品质。1984年从福建农科院耕作所和江苏徐州地区农科引进甘薯16个品种（系）及本地品种在病田中进行自然诱发抗性对比试验，表明了甘薯不同品种（系）对极腐病抗性有明显差异。选用抗病品种…     

综合防治泡桐丛枝病

河南全省约有泡桐三亿株,丛枝病的病株率一般为30—70％,部分严重地区达95％。据调查病树比健树每株每年少生长立木桐村0.0052立方米,全省每年因丛枝病影响,少生长立木桐树23万立方米以上,损失木材价值约5千万元。     

水稻矮缩病毒对3种内源激素含量及代谢相关基因转录水平的影响

本文以抗病品种宜香2292(Oryzas ativa L. ssp. indica cv. Yixiang 2292)为材料,采用高效液相色谱技术(HPLC)和Real-time PCR技术研究了水稻矮缩病毒(Rice dwarfvirus,RDV)胁迫下水稻内源赤霉素(GA3)、生长素(IAA)和脱落酸(ABA)的动态变化。结果表明,受RDV侵染后,病株体内GA3含量显著低于健株,在显症后的第1d和第10d最为明显,分别较健株低6.28和5.92倍;IAA含量呈现波动变化,但病株体内的IAA含量始终较健株低,在显症后的10d最为明显,比健株低3.58倍;与GA3和IAA相反,病株体内ABA的含量始终高于健株,显症后的第1d和第13d最为明显,分别较健株高2.29和2.84倍。Real-time PCR定量检测了植物内源激素相关基因mRNA的表达,结果显示,GA3代谢相关的氧化还原酶基因表现为下调,而IAA和ABA代谢相关的Cullin-1和P-glycoprotein1基因表现出不同程度的上调。以上结果表明:水稻矮缩病的症状表现可能与病株体内的植物内源激素失调有关。     

海南岛几种绿肥作物丛枝病病原体的电子显微镜研究

 在广东省海南岛发现几种绿肥植物:巴西苜蓿、卵叶山蚂蝗、暗紫莱豆、爪哇大豆罹患了植物黄化病害。病株表现症状:植株矮化、枝叶丛生、叶变小、普遍退绿或黄化。电子显微镜观察发现,在病株叶柄韧皮部筛管细胞超薄切片中,存在大量的类菌原体(MLO)。这些菌体形态多样,有些可见菌体内纤维状样核酸物质,有的菌体正处于二分裂、或发芽状态。这些MLO大小分别为170~800nm、170~700nm、250~650nm、375~770nm。由于在病株中发现有MLO存在,而健株中则没有。可以初步认为四种绿肥植物丛枝病是由MLO所致。     

甘薯病毒病检测技术研究

湖北省甘薯病毒病主要有皱缩花叶型、卷叶型、叶片斑点型(含黄斑型和紫环斑型)等三种症状类型。对三种类型的病株样本进行了电镜观察,结果表明,卷叶型、黄斑型和紫环斑型的病株叶片中均有长线形病毒粒子,长度为1 050m~1 650m,形态和大小无明显差异,皱缩花叶型病株叶片中有时也可观察到长线形病毒。用三种症状类型病株与巴西牵牛靠接,巴西牵牛和甘薯植株成活率达90%以上,巴西牵牛染病率可达80%以上。嫁接后的巴西牵牛叶片表现皱缩而且褪绿症状者,电镜检测均有病毒,因此,巴西牵牛可以用作甘薯病毒病诊断的指示植物。     

耐病毒诱导剂NS-83生理活性的测定

 在多种生物测定系统中对比TNS-83与萘乙酸、赤霉酸和激动素的生理活性,证明NS-83确实具有生长素、赤霉素和细胞分裂素的某些生理功能,但又不完全相似于这些激素.在它的组分中可能存在一种新型的植物生长控制物质,值得深入研究.对于这些生理活性与植物病毒病害控制的关系进行了讨论.     

中国甘薯病毒的血清学检测

 作者用4种甘薯病毒抗体(IgG),3种血清学方法(DAS-ELISA、Dot-blot-ELISA和ISEM)对北京,江苏、四川、山东四省(市)的253份甘薯病毒病样品进行了检测。结果表明:上述地区甘薯中普遍存在甘薯羽状斑驳病毒(SPFMV)和甘薯潜隐病毒(SPLV),尚难确定是否存在甘薯轻斑驳病毒(SPMMV)和甘薯花叶菜花叶状病毒(Sweet Potato Caulimo-like Virus,SPCLV)。21%的显症样品同上述4种病毒的抗血清不产生反应,显示我国甘薯上尚存在其它病毒。用Dot blot-ELISA和ISEM检测甘薯病毒比用DAS-ELISA灵敏准确。     

马铃薯病毒性退化与温度的关系及冀中南平原的留种技术

1.通过試驗証明生育期长短不同的馬鈴薯在同时收获的条件下,生育期短,块茎未充分成熟的处理,并未減輕退化程度;在芽眼尚不可能萌动的結薯初期,馬鈴薯植株如处于高温条件下也可能加重退化,从而说明馬鈴薯的退化并非由于过度成熟产生自然衰老,亦非因为高温影响了萌动的芽眼,使其衰老所致。 2.早收及夏播的馬鈴薯,除去可能因为低温有利于馬鈴薯抗病力的增強外,更主要的是由于低温条件不利于花叶型病毒的增殖和运轉,降低了新生块茎內病毒浓度的結果。 3.为了从根本上解决馬鈴薯退化問題,应采取以隔离病源,严格汰除病株病薯,防治媒介昆虫,控制传播等措施为中心,生产无毒种薯,并結合选用耐病品种和二季栽培的留种技术,进行综合防治。 4.在推行二季栽培留种技术时,应适当推迟夏播播期,夏播所用种薯必須春季提早收获,并結合选株、选薯等措施。     

Effect of local inoculum on the spread of sweet potato virus disease: limited infection of susceptible cultivars following widespread cultivation of a resistant sweet potato cultivar

A study compared the spread of sweet potato virus disease (SPVD) into crops of two moderately resistant and initially SPVD-free sweet potato cultivars in northern and southern Mpigi, Uganda. Whiteflies, the vector of sweet potato chlorotic stunt crini virus (SPCSV), a component cause of SPVD, were similarly abundant in farmers' sweet potato fields around Namulonge in northern Mpigi, and Kanoni in southern Mpigi. However, mean incidence of SPVD in farmers' crops neighbouring the trials was higher at Kanoni (13.3%) than at Namulonge (2.8%). Furthermore, spread of SPVD into initially SPVD-free sweet potato plots of two only moderately resistant cultivars was greater in plots at Kanoni than in plots at Namulonge. The SPVD-resistant New Kawogo was the most common cultivar grown in farmers' fields at Namulonge and had few diseased plants, whereas susceptible cultivars with relatively high incidences of disease predominated at Kanoni. Final SPVD incidence in each trial was positively correlated with a measure combining the proximity and level of inoculum in surrounding fields. The study demonstrates the importance of local SPVD inoculum in determining the rate of spread of the disease into fields and implies that the widespread cultivation of a resistant variety limits infection of susceptible cultivars grown nearby.     

Symptoms, aetiology and serological analysis of sweet potato virus disease in Uganda

Sweet potato virus disease (SPVD) is the name used to describe a range of severe symptoms in different cultivars of sweet potato, comprising overall plant stunting combined with leaf narrowing and distortion, and chlorosis, mosaic or vein-clearing. Affected plants of various cultivars were collected from several regions of Uganda. All samples contained the aphid-borne sweet potato feathery mottle potyvirus (SPFMV) and almost all contained the whitefly-borne sweet potato chlorotic stunt closterovirus (SPCSV). SPCSV was detected by a mix of monoclonal antibodies (MAb) previously shown to react only to a Kenyan isolate of SPCSV, but not by a mixture of MAb that detected SPCSV isolates from Nigeria and other countries. Sweet potato chlorotic fleck virus (SPCFV) and sweet potato mild mottle ipomovirus (SPMMV) were seldom detected in SPVD-affected plants, while sweet potato latent virus (SPLV) was never detected. Isolates of SPFMV and SPCSV obtained by insect transmissions together induced typical symptoms of SPVD when graft-inoculated to virus-free sweet potato. SPCSV alone caused stunting and either purpling or yellowing of middle and lower leaves when graft-inoculated to virus-free plants of two cultivars. Similarly diseased naturally inoculated field plants were shown consistently to contain SPCSV. Both this disease and SPVD spread rapidly in a sweet potato crop.     

水稻锯齿叶矮缩病毒抗血清的制备及其应用

 采用人工接种发病的水稻锯齿叶矮缩病株茎叶的榨出液,以低速离心(4000rpm)结合聚乙二醇(PEG)的方法所得部分提纯的病毒,进行家兔免疫注射制备抗血清,结果以注射后3~4周的效价最高,可达1:4096,α-最适比值为1:13。应用这种方法制备成的水稻锯齿叶矮缩病毒(RRSV)的抗血清,进行了水稻矮缩病毒(RDV)病株与RRSV病株的鉴别诊断和RRSV毒源寄主的检测。结果证明,具卷叶、缺刻的RDV病株确非RRSV复合感染所致。毒源寄主测定表明,在供试的7种田间常见杂草中,有5种表现为阳性反应;经生物学回接证实,5种中有蟋蟀草、水蜈蚣和游草3种能成功地将RRSV传给水稻而引起发病。     

甘薯病毒病害SPVD抗性鉴定方法及产量损失估计

为了建立规范、有效的甘薯病毒病害（sweet potato virus disease,SPVD）抗性鉴定方法,于2011—2012连续两年,利用田间人工嫁接病毒接穗的方法对12个甘薯品种进行抗性鉴定和产量损失测定。结果显示,嫁接接种后,接穗成活率接近100%,12个品种都有不同程度发病,病情指数在51.0~95.2之间;感染SPVD的甘薯植株叶绿素含量降低、蔓长缩短;单株薯块产量损失范围在55.1%~97.8%之间。研究表明,供试的12个甘薯主栽品种感染SPVD后均可引起严重的产量损失,且田间人工嫁接病毒接穗是一个有效的SPVD抗性鉴定方法。     

Effects of sweet potato feathery mottle virus and sweet potato sunken vein virus on sweet potato yields and rates of reinfection of virus-Free planting material in Israel

Yield reductions ofca 50% or more were observed in field plots infected with both sweet potato feathery mottle virus (SPFMV) and sweet potato sunken vein virus (SPSVV) (‘complex’), compared with plots planted with virus-free propagation stocks. No yield reductions were observed in a plot planted with SPFMV-infected cuttings. In plots infected with SPSVV alone, no significant effect on tuber yields was observed in one year, whereas in the second year there was aca 30% reduction in yield compared with virus-free control plants. Reinfection in the field, in the absence of introduced infection sources, was observed only with SPSVV. However, natural spread resulted when SPFMV-infected source plants were introduced. This implies that aphid vectors were present during the growing season, but that SPFMV infection sources were absent from the area.     

Seed transmission of Sweet potato leaf curl virus in sweet potato (Ipomoea batatas)

Sweet potato leaf curl virus (SPLCV) infects sweet potato and is a member of the family Geminiviridae (genus Begomovirus). SPLCV transmission occurs from plant to plant mostly via vegetative propagation as well as by the insect vector Bemisia tabaci. When sweet potato seeds were planted and cultivated in a whitefly‐free greenhouse, some sweet potato plants started to show SPLCV‐specific symptoms. SPLCV was detected by PCR from all leaves and floral tissues that showed leaf curl disease symptoms. More than 70% of the seeds harvested from SPLCV‐infected sweet potato plants tested positive for SPLCV. SPLCV was also identified from dissected endosperm and embryos. The transmission level of SPLCV from seeds to seedlings was up to 15%. Southern blot hybridization showed SPLCV‐specific single‐ and double‐stranded DNAs in seedlings germinated from SPLCV‐infected seeds. Taken altogether, the results show that SPLCV in plants of the tested sweet potato cultivars can be transmitted via seeds and SPLCV DNA can replicate in developing seedlings. This is the first seed transmission report of SPLCV in sweet potato plants and also, to the authors' knowledge, the first report of seed transmission for any geminivirus.