豆类炭疽病病原物种类及其发生研究进展

炭疽病是重要的世界性植物病害,造成大豆、绿豆等品质变劣,产量损失严重。本文综述了国内外大豆炭疽病的发生情况、炭疽菌种类及其特征,为了解该病的流行病学和科学防治提供理论依据。     

Biocontrol potential of two novel grapevine associated Bacillus strains for management of anthracnose disease caused by Colletotrichum gloeosporioides

A study was conducted to identify bacterial antagonists for biological control of anthracnose which is one of the economically important diseases of grapes. In India, it is caused by Colletotrichum gloeosporioides. Two hundred and ninety-three bacteria were isolated from the grape ecosystem of 43 spatially distant vineyards in peninsular India. Of these, 25 bacteria substantially inhibited the radial growth of C. gloeosporioides in in vitro studies and 18 bacteria significantly reduced infections in vivo. Of these 18 bacteria, 5 and 3 bacteria also significantly reduced percent disease index (PDI) of downy and powdery mildew diseases, respectively. These bacteria were labelled as strains, DR-38, DR-39, TL-171, DRo-198, TS-204, TS-205, and DR-219, and were identified as Bacillus species based on morphological and molecular characterisation. Aqueous suspensions of all these strains applied as foliar sprays at 1×10⁸ cfu/ml on field grown vines significantly lowered the PDI and the AUDPC (area under disease progress curve) of anthracnose when compared with the untreated control, except DRo-198. Strains TS-204 and TL-171 recorded lower PDIs and AUDPC when compared with the other five strains, and TS-204 could effectively suppress ripe rot of berries, too, in vivo. Strains TS-204 and TL-171 are identified for biocontrol of anthracnose in grapes.     

The antagonistic action of Trichoderma harzianum strain DGA01 against anthracnose-causing pathogen in mango cv. ‘Carabao’

The mechanisms of control and efficacy of Trichoderma harzianum strain DGA01 against anthracnose-causing pathogen Colletotrichum gloeosporioides in mango cv. ‘Carabao’ were examined. The action of DGA01 towards C. gloeosporioides was mycoparasitism and production of metabolites. DGA01 parasitised the pathogen by coiling its mycelia and spores on both artificial media and mango fruit surfaces. DGA01 was a parasitic necrotroph capable of killing C. gloeosporioides in 14 days of coexistence in artificial media. Dipping fruit in conidial suspension (10⁶?mL?L^?1) of DGA01 significantly decreased the incidence of anthracnose as compared to untreated fruit. Reduction in anthracnose severity was 87.90% showing high antagonistic potential of DGA01 in vivo.     

Two Genetically Distinct Populations of Colletotrichum gloeosporioides Penz. Causing Anthracnose Disease of Yam (Dioscorea spp.)

Variation within Colletotrichum gloeosporioides, the causal agent of yam anthracnose disease, is still poorly defined and this hinders breeding for resistance. Two morphotypes of C. gloeosporioides, designated slow‐growing grey (SGG) and fast‐growing salmon (FGS), are associated with anthracnose disease of yam in Nigeria. The morphotypes are distinguishable based on colony and conidial morphology, growth rate, virulence, as well as vegetative compatibility, but molecular differentiation of SGG and FGS strains is needed to facilitate epidemiological studies. Denaturing gradient gel electrophoresis (DGGE) of polymerase chain reaction (PCR)‐amplified small subunit (18S) rDNA fragments, and microsatellite‐primed PCR (MP‐PCR) genomic fingerprinting were employed to provide a basis for molecular differentiation of the morphotypes. DGGE analysis revealed patterns that clearly differentiated isolates of the aggressive defoliating SGG from the moderately virulent non‐defoliating FGS strains. Genetic analysis based on 52 MP‐PCR markers revealed highly significant differentiation between the SGG and FGS populations on yam (G_ST = 0.22; Nei's genetic identity = 0.85; θ = 0.28, P < 0.001), indicating that the SGG and FGS morphotypes represent genetically differentiated populations. The results of the molecular typing using DGGE and MP‐PCR analyses were consistent with the disease phenotype caused by the two morphotypes. Consequently, these molecular techniques might be used, at least partly, to replace time‐consuming virulence studies on yam.     

Molecular fingerprinting of Helicanthus elastica (Desr.) Danser growing on five different hosts by RAPD

Mistletoes are hemiparasitic plants growing on aerial parts of other host trees. Many of the mistletoes are reported to be medicinally important. The hemiparasitic nature of these plants makes their chemical composition dependent on the host on which it grows. They are shown to exhibit morphological dissimilarities also when growing on different hosts. Helicanthus elastica (Desr.) Danser (mango mistletoe) is one such less explored medicinal mistletoe found on almost every mango tree in India. Traditionally, the leaves of this plant are used for checking abortion and for removing stones in the kidney and urinary bladder while significant antioxidant and antimicrobial properties are also attributed to this species of mistletoe. The current study was undertaken to evaluate molecular differences in the genomic DNA of the plant while growing on five different host trees using four random markers employing random amplified polymorphic DNA (RAPD) followed by similarity matrix by Jaccard’s coefficient and distance matrix by hierarchal clustering analysis. Similarity and distance matrix data employing just 4 random markers, separately and the pooled data as well, revealed significant difference in the genomic DNA of H. elastica growing on five different hosts. Pooled data of similarity from all the 4 primers cumulatively showed similarity between 0.256 and 0.311. Distance matrix ranged from of 0.256 to 0.281 on pooling the data from all the four primers. The result employing a minimum number of primers could conclude that genomic DNA of H. elastica differs depending upon the host on which it grows, hence the host must be considered while studying or utilizing this mistletoe for medicinal purposes.     

基于GARP的三种芒果象甲在中国的适生性分析

芒果象甲Sternochetus Pierce昆虫是芒果的重要害虫,明确其可能适牛的区域对该虫的科学监测及防治意义重大.本文利用芒果象甲属中主要3种:印度果核芒果象S.mangiferae Fabricius、果核芒果象S.olivieri Faust、果肉芒果象S.frigidus Fabrieius的已知分布点数据和亚洲地区的14个环境地理变量图层,运用GARP生态位模型结合GIS空间分析模块预测了该虫在中国的潜在地理分布,结果表明芒果象甲具有较强的扩散蔓延趋势,对我国的芒果产业构成较大的潜在威胁.     

Effect of Salicylic Acid Formulations on Induced Plant Defense against Cassava Anthracnose Disease

This study was to investigate defense mechanisms on cassava induced by salicylic acid formulation (SA) against anthracnose disease. Our results indicated that the SA could reduce anthracnose severity in cassava plants up to 33.3% under the greenhouse condition. The β-1,3-glucanase and chitinase enzyme activities were significantly increased at 24 hours after inoculation (HAI) and decrease at 48 HAI after Colletotrichum gloeosporioides challenge inoculation, respectively, for cassava treated with SA formulation. Synchrotron radiation–based Fourier-transform infrared microspectroscopy spectra revealed changes of the C=H stretching vibration (3,000–2,800 cm⁻¹), pectin (1,740–1,700 cm⁻¹), amide I protein (1,700–1,600 cm⁻¹), amide II protein (1,600–1,500 cm⁻¹), lignin (1,515 cm⁻¹) as well as mainly C–O–C of polysaccharides (1,300–1,100 cm⁻¹) in the leaf epidermal and mesophyll tissues treated with SA formulations, compared to those treated with fungicide carbendazim and distilled water after the challenged inoculation with C. gloeosporioides. The results indicate that biochemical changes in cassava leaf treated with SA played an important role in the enhancement of structural and chemical defense mechanisms leading to reduced anthracnose severity.     

Symptoms and Prepenetration Events Associated with the Infection of Common Bean by the Anamorph and Teleomorph of Glomerella cingulata f.sp. phaseoli

Glomerella cingulata f.sp. phaseoli and Colletotrichum lindemuthianum are the teleomorph and anamorph, respectively, of the pathogen causing anthracnose in common bean. The mechanisms relating to the sexual reproduction of this plant pathogen are still unclear, as are the infection structures involved and the symptoms produced. In the present study, bean plants were inoculated with ascospores and conidia, and the events taking place within the following 120 h were investigated using light microscopy and scanning electron microscopy. The symptoms exhibited by plants inoculated with the ascospores were milder than in those inoculated with conidia. Microscopy revealed that most of ascospores produced germ tubes and appressoria at an early stage (24 h after inoculation). From 48 h onwards, the formation of hyphae and the production of germ tubes and appressoria were great. In contrast, infections originating from conidia developed more slowly, and at 24 and 48 h, many non‐germinated conidia were present, whereas only few conidia developed germ tubes and appressoria. Ascospore germination and appressorium formation were similar on both resistant and susceptible cultivars. Hence, the symptoms and the temporal sequence of events associated with the infection of bean plants by the two fungal forms differed, although the structures produced were similar. This is the fist report comparing symptoms and prepenetration events between anamorph and teleomorph of G. cingulata f.sp. phaseoli in common bean.