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1.
Anthracnose disease was detected from dragon fruit (Hylocereus undatus) at a market of Yuanjiang County, Yunnan Province, China. The results of pathogenicity test, morphology studies and sequence analyses based on ITS and β‐tubulin loci indicated that the disease was caused by Colletotrichum truncatum. The pathogen produced elliptic, yellow spots with chlorotic halos on the surface of the fruit, and the lesion become depressed gradually. Grey to black acervuli appeared on the lesion surface in concentric circles later. This is the first report of dragon fruit anthracnose caused by this pathogen in China.  相似文献   

2.
During the year 2008 to 2009, a new disease of stem canker was noticed in most red‐fleshed dragon fruit (Hylocereus polyrhizus) plantations in Malaysia. The symptoms observed were small circular sunken orange spot, black pycnidia and rotted stem. This study was conducted to determine the occurrence of the stem canker on H. polyrhizus in Malaysia, subsequently to isolate, identify and characterize the fungal pathogen based on morphology and molecular characteristics and pathogenicity test. From the surveyed 20 plantations in Malaysia, stem canker was detected in all the plantations. A total of 40 isolates of Scytalidium‐like fungus were isolated and identified as Neoscytalidium dimidiatum based on morphological characteristics and ITS region sequences, which showed 99% similarity to N. dimidiatum (FJ648577). From the phylogenetic analysis using maximum‐likelihood tree, isolates of N. dimidiatum from stem canker of H. polyrhizus were grouped together and did not show any sequence variation. From pathogenicity test, all 40 isolates of N. dimidiatum were pathogenic causing stem canker on H. polyrhizus. To our knowledge, this is the first report of stem canker of H. polyrhizus caused by N. dimidiatum in Malaysia.  相似文献   

3.
During August 2010 and January 2011, 10 isolates of Colletotrichum were recovered from stem anthracnose lesions of Hylocereus polyrhizus in the states of Kedah and Penang, Malaysia. Based on the morphological characteristics of colony colour and appearance, and shapes of conidia as well as sequences of internal transcribed spacer regions (ITS), β‐tubulin, actin (ACT) and glyceraldehyde 3‐phosphate dehydrogenase (GAPDH), the fungus was identified as Colletotrichum truncatum. Pathogenicity test showed that C. truncatum isolates were pathogenic to the artificially inoculated H. polyrhizus stem. This is the first report of C. truncatum causing anthracnose on H. polyrhizus stems in Malaysia.  相似文献   

4.
To study population dynamics of Xanthomonas citri subsp. citri (Xcc) in citrus canker lesions on fruit, a needle‐free injector was used for infiltration of bacterial inoculum into fruit in situ on mature ‘Ruby Red’ grapefruit (Citrus paradisi Macf.) trees in Florida. Inoculations of Xcc at 105 colony‐forming units (cfu) per ml were conducted in 2012 and 2013 on attached fruit varying from 15 mm to 90 mm in diameter. Inoculations were repeated every 2–3 weeks until the fruit were no longer injectable. On fruit less than 40 mm in size, erumpent lesions formed within 2 weeks of inoculation and expanded 1–9 mm in diameter from 30 to 120 days postinoculation (dpi). Xcc populations in lesions were 6–8 log cfu per lesion at 30 dpi and maintained this population up to 90 dpi. By 120 dpi, Xcc populations declined 1–3 log units as rainfall and temperature decreased in September–October. Xcc populations declined to ~3 log cfu per lesion after 120 dpi in November 2012 and 2013, whereas the population resurged to 5 log cfu per lesion after 180 dpi in January–February 2014.  相似文献   

5.
Stem rot was recorded as one of serious diseases of red‐fleshed dragon fruit, (Hylocereus polyrhizus), in Malaysia. Fusarium fujikuroi was recovered from stem rot lesion of H. polyrhizus and the species was identified using TEF1‐α sequence and mating study. From maximum likelihood phylogenetic tree using combined TEF1‐α and β‐tubulin sequences, the F. fujikuroi isolates from stem rot were grouped according to three geographical locations, namely Peninsular Malaysia, Sabah and Sarawak. Phylogenetic analysis indicated that F. fujikuroi isolates from stem rot of H. polyrhizus were clustered separately from F. fujikuroi isolates from rice because of intraspecific variation. From amplification of MAT allele‐specific primers, 20% of the isolates carried MAT‐1 allele while 80% carried MAT‐2 allele. From isolates that carried MAT‐1 allele, 65% crossed‐fertile with MP‐C (mating population of F. fujikuroi) tester strain while for MAT‐2 allele, 56% crossed‐fertile with MP‐C. None of the isolates were identified as MP‐D (mating population of F. proliferatum). Pathogenicity test conducted on 40 representative isolates showed that the stem rot symptoms were similar with the symptoms observed in the field, and can be categorized as low, moderate and high aggressiveness, which indicated variation in pathogenicity and virulence among the isolates. This study provides novel findings regarding Fusarium species associated with stem rot of H. polyrhizus and indicated that F. fujikuroi as a new causal pathogen of the disease.  相似文献   

6.
为筛选火龙果(Hylocereus undatus)优良种质资源,对22份种质资源果实的表型性状、农艺性状、品质性状进行遗传多样性分析。结果表明,火龙果种质资源果实的表型性状、农艺性状和品质性状具有丰富的遗传多样性和较高的变异性,表型性状的多样性指数(H′)为0~1.04,品质性状为0.40~2.01;农艺性状的变异系数(CV)为0.06~0.38,品质性状为0.01~0.62。聚类分析表明,在遗传距离为15时,火龙果22份种质资源可分为5类,说明不同资源间亲缘关系较远。这为发掘火龙果的育种潜力,筛选优异基因资源,改良种质奠定了基础。  相似文献   

7.
During a series of sampling in 2008 and 2009, stem rot disease was detected in Hylocereus polyrhizus plantations in Malaysia, with symptom appeared as circular, brown sunken lesion with orange sporodochia and white mycelium formation on the lesion surface. Eighty‐three isolates of Fusarium were isolated from 20 plantations and were morphologically identified as F. proliferatum based on the variability of colony appearance, pigmentation, growth rate, length of chains, production of bluish sclerotia, concentric ring aerial mycelium and sporodochia. Three species‐specific primers, namely ITS1/proITS‐R, PRO1/2 and Fp3‐F/4‐R successfully produced PCR products and confirmed that the isolates from stem rot of H. polyrhizus were F. proliferatum isolates. From BLAST search of translation elongation factor 1‐alpha (TEF1‐α) sequences, the isolates showed 99–100% similarity with F. proliferatum deposited in GenBank which further confirmed that the isolates were F. proliferatum. The results from amplification of MAT‐allele specific primers indicated that 14.5% of F. proliferatum isolates carried MAT‐1 allele and 85.5% carried MAT‐2. Crossing results showed that all 83 F. proliferatum isolates were male fertile showing positive crosses with the tester strains of MATD‐1 and MATD‐2. Perithecia oozing ascospore were produced. Forty isolates as representative were evaluated for pathogenicity test, produced rot symptoms similar to those observed in the fields which confirmed the isolates as the causal agent of stem rot of H. polyrhizus. To our knowledge, this is the first report of stem rot of H. polyrhizus caused by F. proliferatum in Malaysia.  相似文献   

8.
Aims: To screen micro‐organisms for inducing the production of dragon’s blood, which is normally produced by stem xylem and by leaf of Dracaena cochinchinensis, and to evaluate the product by comparing with the standard. Methods and Results: Thirty microbial strains were isolated from D. cochinchinensis leaves. Three of them were confirmed to elicit the leaf of D. cochinchinensis producing dragon’s blood after inoculation. Upon elicitation, all of the 6‐month‐old leaves of the inducible trees produced dragon’s blood; 60–70% of the 1‐year‐old leaves elicited produced the resin. All the three strains were identified as Colletotrichum gloeosporioide by morphological and molecular methods. The leaf resin had a similar TLC profile and antioxidant activities to the standard resin. In particular, it had a higher total flavonol content and antimicrobial activity than the standard. Conclusions: Upon the induction of the screened C. gloeosporioide mycelia, D. cochinchinensis leaf produced dragon’s blood with higher total flavone content and antimicrobial activity than the standard dragon’s blood. Significance and Impact of the Study: This work has provided a strategy for producing dragon’s blood in a sustainable way using leaves of C. gloeosporioides by fungal elicitation.  相似文献   

9.
Pre-embryonic and embryonic stages and seed developments were studied in the diploids Hylocereus monacanthus and Hylocereus undatus and the tetraploid Hylocereus megalanthus. Ovule morphology was similar among species except for micropyle entrance. H. monacanthus had the thickest and most robust suspensor. Embryo developmental time, measured from fertilization to maturity, was significantly more prolonged in H. megalanthus. Typical to Cactaceae, the seed coat was formed by one layer of sclerenchymatous cells, but was more lignified in H. megalanthus. Morphological features common to all species included (1) cellular type endosperm with independent patterns of development in the chalazal and micropylar zones, forming a haustorium layer from the chalazal zone to the embryo; (2) an endothelial layer surrounding the embryo sac almost complete; (3) a nucellar summit growing into the micropyle; and (4) a placental obturator and a funicle connecting the ovarian tissue to the ovule. Seed development was typically endospermic (exendospermic orthodox seeds). Anomalies included two egg cells in the same embryo sac, two embryos developing in the same ovule, and embryos developing from the chalazal pole region. Total seed number and seed viability were significantly lower in H. megalanthus than in the other two taxa. Embryos at different developmental stages were observed in aborted H. megalanthus seeds.  相似文献   

10.
Aims: To find a formulation of Epicoccum nigrum conidia that enhances its adhesion to peach surfaces and improves its biocontrol efficacy against brown rot caused by Monilinia laxa. Methods and Results: The stickers, glycerol, sodium alginate and methylcellulose; the desiccants, silica powder and talc; and a commercial adhesive (NU FILM 17®) were added at two different points during the production of an E. nigrum conidial formulation to improve conidial adhesion to peach surfaces. Conidial adhesion levels were determined from the number of E. nigrum conidia that adhered to glass slides or peach surfaces and conidial viability of adherent E. nigrum conidia was determined from the number of colony‐forming units of glass or peach‐adherent E. nigrum that grew on Petri dishes that contained potato dextrose agar. Compared to dried E. nigrum conidia without additives, the adhesion and viability of adherent E. nigrum conidia to peach surfaces were enhanced when either 1·25% sodium alginate or 2·5% methylcellulose was added to the conidial mass after fluid‐bed drying, and when 2·5% methylcellulose was added to the conidial mass after its production and before fluid‐bed drying. Epicoccum nigrum conidial formulations with 2·5% methylcellulose were more effective than dried E. nigrum conidia without additives in reducing the incidence of brown rot in peaches caused by M. laxa. Conclusions: When 2·5% methylcellulose is incorporated into an E. nigrum conidial formulation, the adhesion of E. nigrum conidia to peach surfaces improves and results in efficacious biocontrol of brown rot. Significance and Impact of the Study: A new improved formulation of a biocontrol agent has been developed to improve the control of M. laxa on peaches.  相似文献   

11.
以‘金都’火龙果(Hylocereus polyrhizus ‘Jindu’)果实为试材,采用波长254 nm紫外杀菌灯为辐射源,给予不同剂量短波紫外线(Ultraviolet-C,UV-C)照射处理,探讨低剂量UV-C对火龙果采后保鲜的影响及作用机理。结果表明,不同剂量UV-C照射处理能有效抑制‘金都’火龙果果实腐烂和电导率上升,降低果实TSS含量,其中1.0 kJ·m–2紫外线辐照效果最好。1.0 kJ·m–2 UV-C处理能极显著提高贮藏期火龙果的SOD和CAT活性,显著提高贮藏早中期的几丁质酶活性和PPO活性,β-1,3葡聚糖酶活性在贮藏后期也显著高于对照,但降低了火龙果贮藏中期(第6天)的POD活性。此外,1.0 kJ·m–2 UV-C处理显著提高火龙果贮藏期H2O2含量(除第6天外),对果实的失水率无影响。采后火龙果应用适当剂量UV-C照射可提高抗病性,延长贮藏保鲜期。  相似文献   

12.

The current drainage-based peatland management systems in Indonesia result in high fire risks, soil subsidence and CO2 emissions. This study aims to assess different alternatives of peatland crops in order to help prevent further degradation of peatlands in Indonesia. We focus on tropical peatland crops that provide food and that are of particular interest to smallholders. We compare various peatland food crops that are commonly grown with no drainage (paludiculture) or drainage below 50 cm in our study area, Central Kalimantan, Indonesia in terms of sustainability, profitability, scalability of the market and acceptability to farmers. Our results show that sago (Metroxylon sagu), banana (Musa paradisiaca) and pineapple (Ananas comosus) followed by water spinach/kangkong (Ipomoea aquatica), kelakai/edible fern (Stenochlaena palustris), illipe nut/tengkawang (Shorea spp.), dragon fruit (Hylocereus undatus), mangosteen (Garcinia mangostana) and sweet melon/melon (Cucumis melo) are the best options based on the aggregated scores for these criteria (but precaution should be taken when planting crops that require low drainage). Sago palm and illipe nut have the highest scores for both sustainability and scalability of market, whereas banana, pineapple and sweet melon have the highest scores in term of the scalability of market and acceptability to farmers. We also address key opportunities and bottlenecks for the development of paludiculture food crops and present recommendations for the implementation of paludiculture in Indonesian peatlands.

  相似文献   

13.
Vegetative propagation of mulberry (Morus spp.) is greatly afflicted by soilborne diseases. Stem canker (Botryodiplodia theobromae) and cutting rot (Fusarium solani) are the major diseases which cause high rate of mortality of stem‐cuttings (vegetative clones), thus affecting the initial establishment of mulberry. Apart from diseases, the poor rooting ability of stem‐cuttings of many promising mulberry varieties also leads to unproductive propagation. An effective biocontrol agent (Trichoderma pseudokoningii), chemical fungicide (Dithane M‐45) and phytohormones (Indole‐3‐acetic acid, IAA and 1‐Naphthalene acetic acid, NAA) were evaluated individually and in combination for their effects on disease control and plant development. In plates, T. pseudokoningii was found to be compatible with Dithane M‐45 at 0.1%, and IAA and NAA at 20 ppm concentrations. Under field conditions, the integration of soil application of T. pseudokoningii (in the form of its formulated product, ‘NURSERY‐GUARD') and dipping of stem‐cuttings in 0.1% solution of Dithane M‐45, or 20 ppm solution of IAA showed better results than their individual application. NURSERY‐GUARD with Dithane M‐45 (0.1%) or IAA (20 ppm) provided 47.6 to 52.4% disease control to stem‐cuttings which resulted in significant increase (over check) in sprouting of stem‐cuttings (53.1–63.3%) and plant survival (52.6–57.8%).  相似文献   

14.
Agricultural crops especially fruit trees are constrained by edaphic stresses in shallow soils with low water retention and poor fertility. Therefore, interventions of shifting to trench planting for better root anchorage and replacing the filling soil were evaluated for 8 years in dragon fruit (Hylocereus undatus) cultivated in Deccan Plateau of peninsular India. When averaged for last 5-years, 44 % higher fruit yield (18.2 ± 1.0 Mg ha?1) was harvested from trees planted in trenches filled with 1:1 mixture (T-mixed) of native soil (loamy sand with 26.7 % stones (>2mm), field capacity, FC 0.20 cm3 cm?3; organic carbon, OC 0.17 %; Av-N 54.6 kg ha?1) and a black soil (clay 54.4 %; FC 0.42 cm3 cm?3; OC 0.70 %; Av-N 157.1 kg ha?1) than the recommended pit planting (12.4 ± 1.2 Mg ha?1). Improvements in fruit yields with trenches filled with black (T-black) and native (T-native) soil were 32 and 13 %, respectively. Yield losses (total– marketable yield) were reduced by 40, 20 and 18 % over pit method with T-mixed, T-black and T-native soil, respectively. Marketable quality attributes like fruit weight, fruit size metrics and pulp/peel content were further improved under T-mixed soil. Accumulation of total soluble solids (TSS), sugar content, phenolic and flavonoid compounds were higher in fruits from T-native soil. During storage, fruits from T-native soil and pit planting exhibited minimum physiological weight loss and retained more firmness, TSS, sugars, titratable acidity, phenolic-flavonoids contents, FARP and DPPH activities. T-mixed soil provided better hydrozone and nutrients for resilience of fruit plants while protecting from aeration problems envisaged in poorly drained black soils. With B:C ratio (1.85) and lower payback period (4-years), T-mixed soil showed superior economic viability. Therefore, soil management module of planting in trenches filled-in with mixture of native and black soils can be recommended to boost productivity of fruits from shallow soils under water scarce degraded regions without penalising agro-ecosystem.  相似文献   

15.
Four nonpathogenic and nontoxigenic Epicoccum nigrum strains were evaluated for their growth, morphology and pigment producing ability in three complex and one defined liquid media. Epicoccum nigrum IBT 41028 produced pigments in all the four media tested with a maximum pigment of 3.68 AU at 410 nm in M1 medium (unoptimized) containing 5 g/l yeast autolysate. The color hue of the crude pigment extracts ranged from 74 to 102 exhibiting dark orange to green-yellow color. Pelleted morphology was shown to have a positive influence on the pigment production by E. nigrum strain IBT 41028 in the liquid media, and the use of Bis-tris buffer was found to diminish or reduce the pellet formation. Since Monascus is a well known pigment producer on rice. Pigment producing ability of E. nigrum IBT 41028 was tested on rice and compared to liquid media with Monascus ruber IBT 7904 as control. Though, both genera preferred rice but E. nigrum produced 4.6 folds higher pigment in the liquid unoptimized fermentation medium compared to M. ruber. Solid phase extraction and subsequently HPLC-DAD analysis of the crude pigment extracts showed qualitative as well as quantitative variation in the pigment composition under solid and liquid cultivations.  相似文献   

16.
This study investigated the interactions between insecticides (acephate and indoxacarb) and fungal entomopathogens (Beauveria bassiana [Bals.-Criv.] Vuill. strain B27, Metarhizium anisopliae [Metschn.] Sorokin strain ECS1, and a commercial B. bassiana product, Velifer® Biological Insecticide) for controlling the macadamia seed weevil, Kuschelorhynchus macadamiae Jennings and Oberprieler, in the laboratory and glasshouse. In the laboratory, additive interactions between insecticides at their full field concentrations (776 mg AI/L of acephate and 75 mg AI/L of indoxacarb) and fungal entomopathogens at 107 conidia/ml (ECS1 and B27) or at full field concentration (0.5 ml of Velifer®/L) were seen at 6 days and 12 days post-application. Under the same experimental conditions, synergistic interactions against K. macadamiae were observed 6 days post-application when fungal entomopathogens at 2.5 × 106 conidia/ml or at 25% of full field concentration (Velifer®) were co-applied with insecticides at 25% of their full field concentrations, whilst additive interactions were again observed at 12 days post-application. In the glasshouse, additive interactions between insecticides (at full field concentrations) and fungal entomopathogens (at 107 conidia/ml, or at full field concentration for Velifer®) were obtained at 6 days and 12 days post-application. The results from this study suggest that acephate and indoxacarb have both synergistic and additive effects against K. macadamiae when deployed together with fungal entomopathogens, depending on the initial concentrations of mixture components. Combined application of entomopathogens with compatible insecticides promises to provide more effective management of K. macadamiae than individual chemical applications.  相似文献   

17.
Chromosome numbers and meiotic behavior are reported for the climbing cacti species Hylocereus undatus, Hylocereus polyrhizus, and Selenicereus megalanthus. The Hylocereus spp. are diploid (2n = 22), while S. megalanthus is a tetraploid (2n = 44). Irregular chromosome disjunction at anaphase I in pollen mother cells of S. megalanthus is probably the major cause of its reduced pollen viability and may contribute to low seed set, low number of viable seeds and, consequently, low fruit mass. A pollination study confirmed self-incompatibility in H. polyrhizus and a weakened incompatibility reaction in H. undatus and S. megalanthus. Major crossability barriers do not exist between the Hylocereus spp. investigated. Reciprocal intergeneric crosses were successful between Hylocereus spp. and S. megalanthus, suggesting that an Hylocereus sp. might be one of the diploid progenitors of the tetraploid S. megalanthus. The implications of the results on cacti nomenclature and systematics are briefly discussed.  相似文献   

18.
Grape anthracnose, which is caused by Elsinoë ampelina, is a disease that negatively affects grape production. This study aimed to investigate the effects of aeration, temperature, light, and preculture period on the formation of E. ampelina conidia and conidial germination and virulence. The colony morphology on potato dextrose agar (PDA) plates was more diverse than that in PDA bottles. The assessment of different culture methods, temperatures, light conditions, and preculture periods revealed that optimal conidial production occurred on 25‐day‐old colonies grown in PDA bottles at 21°C for 24 hr in the dark. The cultures in PDA bottles consistently produced approximately 5.0 × 106 conidia under these conditions. No conidial formation occurred when the cultures were kept at 25°C in the dark. The highest germination rate of E. ampelina was 80% at 25°C after 24 hr, whereas no germination was observed at 17°C after 12 hr. Pathogenicity tests revealed that symptoms of the disease were observed 4 days postinoculation (dpi) on leaves of Vitis vinifera cv. Red Globe. New conidia were observed on the lesions at 8 dpi. This study provides an effective method for the conidial production of E. ampelina that may also be applicable for other Elsinoë fungal species.  相似文献   

19.
火龙果溃疡病是火龙果生产中常见的病害之一,对火龙果产量和品质的影响较大,近年来火龙果溃疡病的发生频率逐年增加.本研究通过菌丝生长抑制法测定9种杀菌剂对火龙果溃疡病病菌的杀菌活性.结果表明,戊唑·咪鲜胺、肟菌·戊唑醇、吡唑·毒氟磷有较强的抑菌作用,EC50分别为0.0209,0.0762,2.0358mg/L,本研究为生产上防治火龙果溃疡病药剂的筛选提供了参考.  相似文献   

20.
In Brazil, the fungus Neopestalotiopsis (= Pestalotiopsis) is known to cause disease in eucalyptus cuttings. However, although it occurs relatively frequently in cutting nurseries, the pathogenic species have yet to be identified. Thus, the aim of the present work was to perform a morphological and phylogenetic characterization to identify the aetiological agent. For this purpose, the isolates were subjected to a multilocus analysis using the two gene regions β-tubulin (TUB) and the translation elongation factor (TEF). Based on the genomic sequences, two known species and one new species of the pathogen were identified. After confirmation of their pathogenicity, N. australis was confirmed as a new report in eucalyptus. Neopestalotiopsis rosae failed to differ from the control, however, showed internal and external lesion in eucalyptus stem. In addition, in this study, a new species called N. eucalypti was described, causing disease in hybrids eucalyptus. Morphological characterization allowed for the confirmation of the N. australis and N. rosae isolates, primarily based on differences in the size and shape of the conidia. For N. eucalypti, no morphological marker was found that separated it from the other species within the genus. The results confirm the existence of at least three Neopestalotiopsis species as aetiological agents of leaf spot and stem rot in eucalyptus cuttings in Brazil.  相似文献   

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