海南省胡椒主要病害现状初步调查

为明确海南省胡椒主要病害种类及发生情况,对海南省琼海、文昌、万宁、海口、定安、临高、儋州、澄迈、屯昌等9个市(县)进行了调查,结果表明:(1)目前危害海南胡椒生产的主要病害有9种,其中真菌病害5种,为胡椒瘟病、胡椒枯萎病、胡椒根腐病、胡椒炭疽病和胡椒煤烟病;细菌病害1种,为胡椒细菌性叶斑病;病毒病害1种,为胡椒花叶病;其他病害2种,为胡椒根结线虫病和胡椒藻斑病。(2)分布广且危害严重的有胡椒瘟病、胡椒花叶病、胡椒根结线虫病和胡椒枯萎病。     

枯草芽胞杆菌VD18R19在胡椒上的定殖动态及促生作用和对胡椒瘟病的防治效果

生防芽胞杆菌Bacillus subtilis定殖能力是决定其应用效果的关键因素。目前,芽胞杆菌在胡椒上的定殖情况鲜有报道。本研究以生防芽胞杆菌VD18R19为对象,研究其在胡椒根系和叶片表面的定殖动态及其促生长作用和对胡椒瘟病的防治效果。首先利用荧光质粒p AD43-25标记菌株VD18R19;然后通过荧光观测和平板计数方法检测标记菌株在胡椒根系和叶片表面的定殖形态和数量动态;最后通过盆栽试验分别评估了该菌株的促生长作用和对胡椒瘟病的防治效果。结果表明,菌株VD18R19荧光标记成功,且标记具有良好的遗传稳定性(120世代后高达85.33%);该菌株在胡椒根际偏好于根毛区定殖,定殖数量呈先升后降趋势,在处理后第9 d的定殖数量最多(9.88×106 CFU/g),整个30 d的定殖密度均维持在106 CFU/g水平;叶片定殖呈迅速下降趋势,处理后第9 d的定殖密度仅5.13×104 CFU/g,在21 d后基本检测不到该菌株;在不接种病原菌的情况下,菌株VD18R19处理的胡椒苗的株高、叶片数和地上部分鲜重等均显著好于对照,其促生率分别为61.71%、36.18%和106.43%;胡椒瘟病病原菌Phytophthora capsici叶片接种后,菌株VD18R19处理的胡椒苗在发病率和病斑大小上均显著低于对照,对胡椒瘟病的防治效果达76.86%。以上研究结果揭示了芽胞杆菌VD18R19在胡椒上的定殖动态及其防治效果,对该菌的开发应用有重要指导意义。     

唐山地区姜瘟病发生动态及发病因子调查

针对2017—2019年唐山地区姜瘟病的发生动态及发病因子开展调查研究。结果表明,唐山地区姜瘟病为害严重,地上部茎叶和地下根茎均能感病,常引起全株枯死。2017—2018年定点监测,姜瘟病发病率在9.80%～11.52%之间,6月下旬始发,7月中旬至8月下旬为病害流行盛期,9月中旬以后病情逐渐趋于稳定。姜瘟病的发生流行程度受气温、降雨量等因素影响。当日均气温达到23.5℃以上开始发病,随降雨量的增多病害蔓延加速。唐山地区6个主栽品种以本地品种冀姜5号田间自然发病较轻,另外5个外地引入品种病株率、病情指数均明显偏高,提示外地调入的带菌姜种是主要侵染源。此外,随土壤连作年限的延长和化肥施入量的增加,姜瘟病发病率显著提高。     

成县大蒜白腐病发生规律及综合防治技术

大蒜白腐病(Sclerotium cepivorum Berk.)在成县群众称为大蒜瘟病,是甘肃东南部大蒜主产区主要病害之一.近年来,随着大蒜种植面积的扩大,该病发生为害日趋严重,直接影响着当地大蒜生产的发展.为了有效控制该病的发生为害,提高大蒜生产效益,笔者从1997年起对该病的发生规律及综合防治技术进行了调查研究.     

封面说明

正生防芽胞杆菌Bacillus subtilis定殖能力是决定其应用效果的关键因素。目前,芽胞杆菌在胡椒上的定殖情况鲜有报道。高圣风等以生防芽胞杆菌VD18R19为对象,研究其在胡椒根系和叶片表面的定殖动态及其促生长作用和对胡椒瘟病的防治效果(正文见650~657页)。     

硬枝黄蝉乙醇提取物中抑制胡椒瘟病菌活性成分研究

为研究硬枝黄蝉Allemanda neriifolia Hook.乙醇提取物的抑菌活性, 本研究采用减压柱层析?薄层色谱等对其乙醇提取物的抑菌成分进行了初步分离, 以胡椒瘟病菌Phytophthora capsici为供试病原菌, 测定了不同馏分对胡椒瘟病菌的抑菌活性?结果表明, 石油醚萃取组分(AN-LS1)?氯仿萃取组分(AN-LS2)?乙酸乙酯萃取组分(AN-LS3)对胡椒瘟病菌均具有一定抑菌活性, 抑制率分别为69.59%?66.73%和15.10%?对3种萃取组分采用活性跟踪分离, 发现馏分AN-LS1-05?AN-LS1-06?AN-LS2-03?AN-LS2-04?AN-LS2-05?AN-LS3-02?AN-LS3-03对胡椒瘟病菌抑制率达到了100%, 馏分AN-LS2-06?AN-LS2-07和AN-LS3-04抑制率达到了80%?对各馏分进一步分离最终得到AN-LS1-05-04?AN-LS1-07-07?AN-LS2-04-04?AN-LS2-06-05-06?AN-LS3-04-06等16个化合物, 其化学结构有待进一步鉴定?     

海南岛胡椒病原根结线虫种类鉴定

对海南岛12个县市胡椒产区的27个胡椒病原根结线虫种群进行了纯化培养,运用形态学、同工酶技术及mtDNA扩增技术进行了种类鉴定,结果发现27个纯培养种群中有26个是南方根结线虫,1个是花生根结线虫,南方根结线虫占了96.3％。     

胡椒黄化病研究初报

胡椒是世界上重要的香辛作物之一,在我国广东、广西、云南、福建等4省区均有栽种。华南热作研究院植保所和华南热带作物学院植保系1976—1980年华南4省(区)热带作物病虫害普查中,曾发现福建省云霄县有胡椒黄萎病发生,当时未鉴定出病原。     

泰安郊区小麦田蚜虫两类天敌发生与流行的初步研究

对泰安郊区小麦田蚜虫病原真菌和寄生蜂的发生情况进行了2年的调查,探讨了两类天敌的发生与气候因子和生物因素的关系。结果显示:麦蚜真菌病的发生水平与温度和降雨量成显著的正相关关系,与蚜虫密度成极显著的负相关。寄生蜂的寄生率与温度成极显著的正相关,而与蚜虫密度、相对湿度和降雨量均成显著的负相关。定量地描述了感菌有翅蚜在整个真菌病发生期间所发挥的作用。     

气象因子对晚稻细菌性条斑病发病程度的影响

应用通径分析原理,对1989～2006年化州市晚稻细菌性条斑病发生的历史资料进行分析,明确在气象因子中,雨日是影响该病发病程度的主导因子,平均相对湿度、降雨量、平均气温、日照时数等对该病发病程度的直接作用较小,但通过雨日发挥明显的间接作用。     

Real-Time Polymerase Chain Reaction Quantification of Phytophthora capsici in Different Pepper Genotypes

ABSTRACT Reliable and sensitive quantification of Phytophthora capsici in pepper plants is of crucial importance in managing the multiple syndromes caused by this pathogen. A real-time polymerase chain reaction (PCR) assay was developed for the determination of P. capsici in pepper tissues. DNA levels of a highly virulent and a less virulent isolate were measured in different pepper genotypes with varying degrees of resistance. Using SYBR Green and specific primers for P. capsici, the minimal amount of pathogen DNA quantified was 10 pg. Pathogen DNA was recorded as early as 8 h postinoculation. Thereafter, the increase was rapid in susceptible cultivars and slower in resistant ones. The amount of pathogen DNA quantified in each pepper genotype correlated with susceptibility to Phytophthora root rot. Likewise, there was a relationship between the virulence of the pathogen and the degree of colonization. Differences also were found in oomycete amount among pepper tissues, with maximal pathogen biomass occurring in stems. The real-time PCR technique developed in this study was sensitive and robust enough to assess both pathogen development and resistance to Phytophthora root rot in different pepper genotypes.     

Distribution of Phytophthora spp. in Field Soils Determined by Immunoassay

ABSTRACT Populations of Phytophthora spp. were determined by enzyme-linked immunosorbent assay (ELISA) in field soils used for pepper and soybean production in Ohio. Soybean fields were sampled extensively (64 fields, n = 6 samples per field over 2 years) and intensively (4 fields, n = 64 samples per field in 1 year) to assess heterogeneity of P. sojae populations. Four pepper fields (n = 64), three of which had a history of Phytophthora blight (caused by P. capsici), also were sampled intensively during a 6-month period. Mean (m), variance (v), and measures of aggregation (e.g., variance-to-mean ratio [v/m]) of immunoassay values, translated to Phytophthora antigen units (PAU), were related to the disease history in each of the pepper and soybean fields. Mean PAU values for fields in which Phytophthora root rot (soybean) or blight (pepper) had been moderate to severe were higher than in fields in which disease incidence had been low or not observed. A detection threshold value of 11.3 PAU was calculated with values for 64 samples from one pepper field, all of which tested negative for Phytophthora by bioassay and ELISA. Seven of the eight intensively sampled fields contained at least some detectable Phytophthora propagules, with the percentage of positive samples ranging from 1.6 to 73.4. Mean PAU values ranged from 1 to 84 (extensive soybean field sampling), 6 to 24 (intensive soybean field sampling), and 4 to 30 (intensive pepper field sampling); however, variances ranged from 0 to 7,774 (extensive sampling), 30 to 848 (intensive soybean field sampling), and 5 to 2,401 (intensive pepper field sampling). Heterogeneity of PAU was high in most individual soybean and pepper fields, with values of v/m greater than 1, and log(v) increasing with log(m), with a slope of about 2.0. Spatial autocorrelation coefficients were not significant, indicating there was no relationship of PAU values in neighboring sampling units (i.e., field locations) of the intensively sampled fields. Combined results for autocorrelations and v/m values indicate that Phytophthora was highly aggregated in these fields but that the scale of the aggregation (e.g., average focus size) was less than the size of the sampling units. Because of the observed variability, we calculated that sample sizes of 20 or more would be needed to estimate precisely the mean density of Phytophthora in most cases.     

Tissue specific colonization of Phytophthora capsici in Capsicum spp.: molecular insights over plant-pathogen interaction

Phytoparasitica - Root and crown rot (RCR) caused by Phytophthora capsici is present in all crop production areas of pepper and chili worldwide. This pathogen was recently reported at the Pacific...     

Root treatment with rhizobacteria antagonistic to Phytophthora blight affects anthracnose occurrence, ripening, and yield of pepper fruit in the plastic house and field

We previously selected rhizobacterial strains CCR04, CCR80, GSE09, ISE13, and ISE14, which were antagonistic to Phytophthora blight of pepper. In this study, we investigated the effects of root treatment of rhizobacteria on anthracnose occurrence, ripening, and yield of pepper fruit in the plastic house and field in 2008 and 2009. We also examined the effects of volatiles produced by the strains on fruit ripening and on mycelial growth and spore development of Colletotrichum acutatum and Phytophthora capsici in the laboratory, identifying the volatile compounds by gas chromatography-mass spectrometry (GC-MS). In the house tests, all strains significantly (P < 0.05) reduced anthracnose incidence on pepper fruit; strains GSE09 and ISE14 consistently produced higher numbers of pepper fruit or increased the fresh weight of red fruit more than the controls in both years. In the field tests, all strains significantly (P < 0.05) reduced anthracnose occurrence on either green or red pepper fruit; strain ISE14 consistently produced higher numbers or increased fresh weights of red fruit more than the controls in both years. In the laboratory tests, volatiles produced by strains GSE09 and ISE13 only stimulated maturation of pepper fruit from green (unripe) to red (ripe) fruit; the volatiles of certain strains inhibited the growth and development of C. acutatum and P. capsici. On the other hand, GC-MS analysis of volatiles of strains GSE09 and ISE13 revealed 17 distinct compounds in both strains, including decane, dodecane, 1,3-di-tert-butylbenzene, tetradecane, 2,4-di-tert-butylphenol, and hexadecane. Among these compounds, 2,4-di-tert-butylphenol only stimulated fruit ripening and inhibited growth and development of the pathogens. Taken together, strains GSE09 and ISE14 effectively reduced anthracnose occurrence and stimulated pepper fruit ripening and yield, possibly via bacterial volatiles. Therefore, these two strains could be potential agents for controlling Phytophthora blight and anthracnose, and for increasing fruit ripening and yield. To our knowledge, this is the first report of volatiles such as 2,4-di-tert-butylphenol produced by rhizobacteria being related to both fruit ripening and pathogen inhibition.     

Identification and development of molecular markers linked to Phytophthora root rot resistance in pepper (Capsicum annuum L.)

Phytopthora root rot in pepper (C. annuum) is caused by Phytophthora capsici L., which exhibits a high level of pathogenic diversity. Resistance to this disease is conditioned by a number of quantitative trait loci. Pyramiding resistance alleles is desirable and could be simplified by the use of molecular markers tightly linked to the resistance genes. The purpose of this study was development of molecular markers linked to Phytophthora root rot resistance. An F₈ recombinant inbred line (RIL) population derived from a cross between YCM334 and a susceptible cultivar ‘Tean’ was used in combination with bulk segregant analysis utilizing RAPD and conversion of AFLP markers linked to Phytophtora root rot resistance into sequence-characterized amplified region (SCAR) markers. In conversion: one marker was successfully converted into a co-dominant SCAR marker SA133_4 linked to the trait. In bulked segregant analysis (BSA): three RAPD primers (UBC484, 504, and 553) produced polymorphisms between DNA pools among 400 primers screened. Genetic linkage analysis showed that the SCAR and RAPD markers were located on chromosome 5 of pepper. Quantitative trait locus (QTL) analysis showed that the SA133_4 and UBC553 were linked to Phytophtora root rot resistance. These markers were correctly identified as resistant or susceptible in nine promising commercial pepper varieties. These markers will be beneficial for marker-assisted selection in pepper breeding.     

Pathogenicity of plant and soil isolates of <Emphasis Type="Italic">Phytophthora parasitica</Emphasis> on tomato and pepper

Crown and root rot of tomato and sweet pepper can be caused by Phytophthora parasitica. In this work, 23 P. parasitica isolates from diseased pepper or tomato plants as well as 54 isolates from 23 monocrop tomato soils (from Spain and Chile) and one from a pepper soil were studied for their host–pathogen response. Results show significant host specificity for the isolates from tomato plants and tomato soils (63 of 64 isolates were unable to cause disease in pepper). None of the pepper plant/soil isolates showed pathogenicity on tomato, and only four of 14 reproduced their pathogenicity on pepper. Only one tomato isolate was pathogenic to both Solanaceae species. Two different inoculation protocols were evaluated (substrate irrigation and stem cutting). All isolates which expressed pathogenicity when stem inoculated also did it when root inoculated, but not vice-versa. Therefore, the recommended test protocol for tomato and pepper breeding programmes is that based on root inoculation by irrigation.     

Detection and Identification of <Emphasis Type="Italic">Phytophthora</Emphasis> Species in Southern Italy by RFLP and Sequence Analysis of PCR-amplified Nuclear Ribosomal DNA

In four neighbouring regions of southern Italy, Basilicata, Campania, Apulia and Calabria, pepper and zucchini plants showing Phytophthora blight symptoms, tomato plants with either late blight or buckeye rot symptoms, plants of strawberry showing crown rot symptoms and declining clementine trees with root and fruit rot were examined for Phytophthora infections by means of polymerase chain reaction (PCR) assays, using primers directed to nuclear ribosomal DNA (rDNA) repeat sequences. All diseased plants and trees examined tested positive. The detected fungal-like organisms were differentiated and characterized on the basis of primer specificity as well as through extensive restriction fragment length polymorphism (RFLP) and sequence analysis of PCR-amplified rDNA. Phytophthora capsici was identified in diseased pepper and zucchini plants, P. infestans was identified in tomato with late blight symptoms whereas buckeye rot-affected tomatoes and diseased strawberry plants proved to be infected by P. nicotianae and P. cactorum, respectively. Declining clementine trees were infected with P. citrophthora and P. nicotianae in about the same proportion. Also, thirty-one pure culture-maintained isolates of Phytophthora which had previously been identified in southern Italy by traditional methods but were never examined molecularly, were examined by RFLP and sequence analysis of PCR-amplified nuclear rDNA. Among these, an isolate from gerbera which had previously been identified by traditional methods only at genus level, was assigned to P. tentaculata. For the remaining pure culture-maintained isolates examined, the molecular identification data obtained corresponded with those delineated by traditional methods. Most of the diseases examined were already known to occur in southern Italy but the pathogens were molecularly detected and fully characterized at nuclear rDNA repeat level only from other geographic areas, very often outside Italy. A new disease to southern Italy was the Phytophthora blight of zucchini. This is also the first report on the presence and molecular identification of P. tentaculata from Italy.     

辣椒中L型凝集素类受体激酶CaLecRKs鉴定及其对辣椒疫霉的响应

L型凝集素类受体激酶(LecRKs)广泛参与植物的先天免疫过程。目前未见在辣椒Capsicum annuum中全基因组鉴定LecRKs的报道。本研究对辣椒中的CaLecRK进行了全基因组鉴定, 并在接种辣椒疫霉Phytophthora capsici条件下通过基因表达分析探究其对辣椒疫霉的响应情况, 旨在挖掘参与辣椒抗疫病防御反应的CaLecRK基因。研究结果表明, 辣椒基因组中共鉴定出24个CaLecRK, 以其构建系统发育树发现, 可将24个CaLecRK分为7个分支。基因表达分析结果显示, 有4个CaLecRK基因(CaLecRK2.2、CaLecRK3.2、CaLecRK8.1和CaLecRK10.1)受辣椒疫霉诱导, 和接菌后0 h相比, 接菌处理后12 h 或36 h基因表达差异显著, 推测其在辣椒抗疫病防御反应中发挥了重要作用。     

枯草芽胞杆菌B1409对番茄和辣椒的防病促生作用

为探讨枯草芽胞杆菌Bacillus subtilis菌株B1409对番茄早疫病和辣椒疫霉病的防效和生防机制,采用平板对峙法和盆栽法测定了该菌株对番茄早疫病菌和辣椒疫霉病菌菌丝生长的抑制作用、对2种病害的盆栽防效以及对番茄和辣椒植株促生长效果和防御酶活性的影响。结果表明:菌株B1409能明显抑制番茄早疫病菌和辣椒疫霉病菌菌丝生长,且导致菌丝发生畸变。10~8CFU/mL菌株B1409菌液对番茄早疫病和辣椒疫霉病的预防效果分别为67.82%和61.22%,治疗效果分别为41.22%和56.43%。不同浓度B1409菌液均能促进番茄和辣椒植株生长,并能增强其体内超氧化物歧化酶、过氧化物酶和过氧化氢酶活性,且浓度越高促进效果越明显。番茄和辣椒植株的平均干重分别在10~2CFU/mL和10~4CFU/mL B1409菌液处理后显著高于对照,增长率分别为42.35%和4.87%。番茄和辣椒植株经10~2CFU/mL B1409菌液处理后,体内超氧化物歧化酶活性比对照显著增加,增长率分别为91.23%和19.58%。研究表明枯草芽胞杆菌B1409菌株可通过直接抑制菌丝生长及诱导植物体自身抗病性等方式来有效防治番茄早疫病和辣椒疫霉病。