Sambutoxin-Producing Isolates of Fusarium Species and Occurrence of Sambutoxin in Rotten Potato Tubers

A total of 50 Fusarium isolates representing 13 species from various sources were surveyed to determine their potential to produce sambutoxin. Sambutoxin production was restricted to Fusarium sambucinum and F. oxysporum, with the exception of one isolate of F. semitectum. Sambutoxin was produced by high percentages of F. sambucinum (80.0%) and F. oxysporum (84.6%) isolates at levels of 1.1 to 101.0 (mu)g/g. In addition, 9 (42.9%) of 21 rotten potato samples were contaminated with sambutoxin at levels of 15.8 to 78.1 ng/g.     

Development of Epidermis on Banana Fruits

Fruit epidermis ofMusa (AAB) cv. Poovan (S) remains single-layered throughout its development. There is no change in stomatal number but its frequency and index decrease due to slight increase in epidermal cell number and size. The external wall of the epidermal cells shows stratification of wall layers that is characteristic of normal epidermal cell with cuticle and epicuticular wax deposits. Surface wax deposits show qualitative and quantitative variations during fruit development and ripening.     

The Occurrence and Pathogenicity of Cylindrocarpon, Cylindrocladium and Fusarium on Calluna vulgaris and Erica spp. in England and Scotland

Cylindrocarpon, Cylindrocladium and Fusarium spp. were often isolated from the woody roots, stem-base and lower foliage of diseased container-grown Calluna vulgaris and Erica spp. plants collected from English and Scottish nurseries. The highest isolation frequencies were obtained for Cylindrocarpon destructans, Cylindrocladium scoparium, Cylindrocladium ilicicola. Fusarium tricinctum, Fusarium avenaceum and Fusarium sporotrichioides . Isolations of these fungi were made more frequently from diseased plants that were at least 1-year-old. The percentage incidence of Cylindrocarpon, Cylindrocladium and Fusarium spp. did not differ between Scottish and English nurseries. Cylindrocarpon destructans. Cylindrocladium ilicicola and C. scoparium were more pathogenic to rooted C. vulgaris cuttings than F. tricinctum. F. avenaceum or F. sporotrichioides in laboratory and glasshouse tests. The high isolation frequency of Cylindrocarpon. Cylindrocladium and Fusarium spp., and their pathogenicity in tests, suggests that these fungi are involved in root, stem-base and lower foliage diseases in crops of C. vulgaris and Erica spp. The importance of these findings for the integrated control of diseases on ericaceous plant nurseries is discussed.     

Silicon Suppresses Fusarium Wilt Development in Banana Plants

This study aimed to determine the effect of silicon (Si) in reducing the symptoms of Fusarium wilt, caused by Fusarium oxysporum f. sp. cubense (Foc), on banana plants. Banana seedlings of Grand Nain (resistant) and Maçã (susceptible) were grown in plastic trays amended with 0 (?Si) or 0.39 g Si (+Si) per kg of soil and inoculated with Foc at 60 days after transplanting. The Si concentration in the roots and rhizome‐pseudostem significantly increased by 30.26 and 58.82%, respectively, for the +Si treatment compared with ?Si treatment. The Si concentration in the roots and rhizome‐pseudostem of Grand Nain plants was, respectively, 11.57 and 37.04% greater than that found in Maçã. The +Si plants showed a reduction of 12.37, 49.81, 51.87 and 20.39%, respectively, for the area under reflex leaf symptoms progress curve, the area under root symptoms progress curve, the area under disease progress curve and the area under asymptomatic fungal colonization of tissue progress curve compared with ‐Si plants. The area under darkening of rhizome‐pseudostem progress curve (AUDRPPC) of Maçã significantly increased by 15.98% for the ?Si treatment in comparison with the +Si treatment. For the +Si treatment, the AUDRPPC of the plants from the Maçã cultivar significantly decreased by 20.59% in comparison with the plants from the Grand Nain cultivar. The area under relative lesion length progress curve (AURLLPC) of the plants from the Maçã cultivar significantly decreased by 41.54% for the +Si treatment in comparison with the ?Si treatment. There was no significant difference between the ‐Si and +Si treatments in the AUDRPPC and AURLLPC of Grand Nain. For the +Si treatment, the AURLLPC of Grand Nain significantly decreased by 9.23% in comparison with Maçã. There was no significant difference between the Grand Nain and Maçã for the AUDRPPC and AURLLPC in the ?Si treatment. The findings of this study show that supplying Si to banana plants, especially to a susceptible cultivar to Foc, had a great potential in reducing the intensity of Fusarium wilt and may play a key role in disease management when banana plants are cultivated in Si‐deficient soils infested by this pathogen.     

壳聚糖在香蕉果实贮藏保鲜上的应用效果

以巴西香蕉果实为材料,研究了不同浓度（0、0．5％、1．0％、2．0％）的壳聚糖溶液对香蕉果实贮藏保鲜的影响。结果表明：壳聚糖处理可明显延缓香蕉果实的软化进程和病情指数的升高;同时维持了果实较低的细胞膜透性、多酚氧化酶（PPO）活性和较高的苯丙氨酸解氨酶（PAL）、β-1,3-葡聚糖酶（GUN）的活性。在四种处理中,以2％壳聚糖处理效果最好。表明壳聚糖对香蕉果实的贮藏保鲜效应可能与其调控病害相关酶的活性有关。     

Occurrence of Zearalenols (Diastereomeric Mixture) in Corn Stalk Rot and Their Production by Associated Fusarium Species

Zearalenol was extracted from Fusarium-infected stems of corn from southern Italy. The toxin, which appeared as a single compound in various thin-layer chromatography systems, was resolved by high-pressure liquid chromatography into two components. A gas chromatography-mass spectrometry examination of a purified fraction confirmed the natural occurrence of zearalenol as a diastereomeric mixture and led to the identification of alpha (56 ng/g) and beta (27 ng/g) isomers. Among nine Fusarium species found associated with stalk rot in corn, only Fusarium culmorum (F. roseum `Culmorum') and F. equiseti (F. roseum `Gibbosum') produced zearalenol and always produced it in a diastereomeric mixture of alpha and beta isomers.     

Analysis of Pectic Enzyme Zymograms of Fusarium Species I. Fusarium lateritium and Related Species

Abstract Zymograms of the extracellular pectic enzymes (pectinesterase, polygalacturonase) of Fusarium lateritium and related species were prepared by electrophoresis from untreated culture filtrates. The zymogram technique gave evidence to conclude that F. lateritium, F. stilboides and F. xylarioides are distinct species. "pini" isolates are rather "subglutinans"-like fusaria than "lateritium"-like, while F. udum represents a genetical variant of F. oxysprorum .     

Pathogenicity of Phaeoacremonium Species on Grapevines

Several Phaeoacremonium species have been recently described to include some species involved in disease of decline of woody plants and others associated with human infections. Thirteen species are currently reported on grapevines and they are suspected to be involved in Esca and Petri disease. The pathogenic character of new defined species is still unknown and, therefore, pathogenicity studies were conducted in this work. The pathogenicity of the following species was studied on grapevine seedlings and cuttings: Phaeoacremonium aleophilum , P. angustius , P. inflatipes , P. krajdenii , P. mortoniae , P. parasiticum , P. scolyti , P. venezuelense , P. viticola , and Phaeomoniella chlamydospora included as positive control. Two-month-old grapevine seedlings of Vitis vinifera cv. Malvar and cv. Airen were inoculated by watering 10 individual pots with a spore suspension (10⁷ spores/ml) of each Phaeoacremonium species. All inoculated seedlings showed typical symptoms of a vascular disease 2 months after inoculation. Grapevine cuttings of Vitis vinifera cv. Monastrell were vacuum-inoculated with a spore suspension (10⁸ spores/ml) and individually planted. Plants rated after 5 months showed that all Phaeoacremonium species and P. chlamydospora (used as positive control) caused a significant vascular discoloration, while only Phaeomoniella chlamydospora , Phaoeacremonium mortoniae and P. aleophilum caused a significant root weight reduction compared with a non-inoculated control. Phaoeacremonium parasiticum , P. angustius , P. inflatipes and P. venezuelense caused significant foliar symptoms that included interveinal chlorosis and stunted leaves.     

海南省香蕉枯萎病病原菌的鉴定

香蕉枯萎病在海南省为首次报道。在Komada改良培养基鉴定的基础上,用温室人工接种法对采自海南省各市县香蕉种植区的18个香蕉和粉蕉假茎分离物进行鉴定。结果表明香蕉枯萎病菌的两种分离物在培养特性和致病性上存在明显区别,分离自粉蕉的12个菌株为1号生理小种,而分离自香蕉的6个菌株为4号生理小种。     

小麦赤霉病镰孢菌毒素的生物合成及其分子调控

禾谷镰刀菌是小麦赤霉病的主要致病菌,其真菌次生代谢产生的单端孢霉烯类B型毒素,如雪腐镰刀菌烯醇(nivalenol,NIV)、脱氧雪腐镰刀菌烯醇(deoxynivalenol,DON)和其它乙酰化衍生物等污染小麦籽粒后对人畜健康构成威胁。综述了近年来国内外对小麦赤霉病镰孢菌单端孢霉烯类B型毒素生物合成的主要途径及分子调控研究进展,对毒素合成过程中的重要调控基因如TRI5、TRI7和TRI13在农业中的应用进行了阐述。     

Pathogenicity of Fusarium oxysporum to Easter lily, narcissus and gladiolus

Isolates of Fusarium oxysporum from roots, bulbs and stems of Easter lilies (Lilium longiflorum) differed widely in pathogenicity and also, apparently, in tissue specificity. Virulent isolates caused a typical basal rot and root rot (but not a wilt) in which the mycelium advanced intercellularly through the scales and basal plates. Mildly pathogenic isolates became established in mature or senescent outer scales, at first producing only superficial effects, but further growth of mycelium occurred as the outer scales died and sometimes continued until the dead tissues were permeated and chlamydospores were formed. The underlying scales were then colonized. The modes of pathogenicity and survival in Easter lily were compared with those of the F. oxysporum formae causing bulb rots of gladiolus and narcissus. It is suggested that advance of hyphae by penetration between the cells of the vascular parenchyma, which is common in isolates causing rots in bulbs and corms, represents a stage in the evolution of the truly vascular habit among fusaria.     

Distribution of Zearalenone-Producing Fusarium Species in Japan

One hundred sixty-six isolates of Fusarium spp. from domestic cereal grains, feed, and other sources were examined for their ability to produce zearalenone on autoclaved moist rice grains. They belonged to the following species (number of producers/number tested): F. roseum (9/28), F. roseum (Culmorum) (3/4), F. roseum (Gibbosum) (2/5), F. roseum (Avenaceum) (1/2), F. roseum (Scirpi) (0/1), F. tricinctum (1/4), F. tricinctum (Sporotrichiella) (0/7), F. lateritium (1/1), F. episphaeria (0/2), F. moniliforme (0/3), F. oxysporum (0/12), F. rigidiusculum (0/4), F. solani (0/4), F. splendens (0/1), F. nivale (0/2), and Fusarium spp. (15/86). Zearalenone was isolated from molded rice by ethanol extraction and purified by column chromatography. Selected isolates of F. roseum M-3-2 and F. roseum (Gibbosum) A-O-2 produced 50 to 100 mg of zearalenone per kg of rice. Increased yields (250 to 407 mg/kg of rice) were obtained by F. roseum M-3-2 when the substrate was supplemented with 1% peptone.     

Beauvericin Production by Fusarium Species

Beauvericin is a cyclohexadepsipeptide mycotoxin which has insecticidal properties and which can induce apoptosis in mammalian cells. Beauvericin is produced by some entomo- and phytopathogenic Fusarium species (Fusarium proliferatum, F. semitectum, and F. subglutinans) and occurs naturally on corn and corn-based foods and feeds infected by Fusarium spp. We tested 94 Fusarium isolates belonging to 25 taxa, 21 in 6 of the 12 sections of the Fusarium genus and 4 that have been described recently, for the ability to produce beauvericin. Beauvericin was produced by the following species (with the number of toxigenic strains compared with the number of tested strains given in parentheses): Fusarium acuminatum var. acuminatum (1 of 4), Fusarium acuminatum var. armeniacum (1 of 3), F. anthophilum (1 of 2), F. avenaceum (1 of 6), F. beomiforme (1 of 1), F. dlamini (2 of 2), F. equiseti (2 of 3), F. longipes (1 of 2), F. nygamai (2 of 2), F. oxysporum (4 of 7), F. poae (4 of 4), F. sambucinum (12 of 14), and F. subglutinans (3 of 3). These results indicate that beauvericin is produced by many species in the genus Fusarium and that it may be a contaminant of cereals other than maize.     

Development of PCR-RFLP Technique for Identify Several Members of Fusarium incarnatum-equiseti Species Complex and Fusarium fujikuroi Species Complex

Fusarium incarnatum-equiseti species complex (FIESC) contain over 40 members. The primer pair Smibo1FM/Semi1RM on the RPB2 partial gene has been reported to be able to identify Fusarium semitectum. The F. fujikuroi species complex (FFSC) contains more than 50 members. The F. verticillioides as a member of this complex can be identified by using VER1/VER2 primer pair on the CaM partial gene. In this research, the Smibo1FM/Semi1RM can amplify F. sulawesiense, F. hainanense, F. bubalinum, and F. tanahbumbuense, members of FIESC at 424 bp. The VER1/VER2 can amplify F. verticillioides, F. andiyazi, and F. pseudocircinatum, members of FFSC at 578 bp. Polymerase chain reaction-restriction fragment length polymorphism by using the combination of three restriction enzymes EcoRV, MspI, and HpyAV can differentiate each species of FIESC used. The two restriction enzymes HpaII and NspI can distinguish each species of FFSC used. The proper identification process is required for pathogen control in the field in order to reduce crop yield loss.     

Zearalenone Production by Fusarium Species

One-hundred-and-thirteen isolates of Fusarium were tested for their ability to produce zearalenone on autoclaved corn. They belonged to the following species (number of producers per number tested): F. epispheria, (0/1); F. moniliforme, (0/8); Gibberella fujikuroi, (0/3); F. nivale, (0/7); F. oxysporum, (0/15); F. roseum, (31/51); F. solani, (0/9); F. tricinctum (3/19). The isolates of individual species produced the following amounts of zearalenone per gram of corn: 3 isolates of F. roseum (0.6 to 119 mug), 3 of F. roseum "Culmorum" (1 to 210 mug), 3 of F. roseum "Equiseti" (0.6 to 2.0 mug), F. roseum "Gibbosum" (115 to 175 mug), 21 of F. roseum "Graminearum" (0.2 to 230 mug), and 3 of F. tricinctum (0.2 to 6.0 mug). All isolates of F. roseum "Graminearum" which formed the perithecial stage of G. zeae (G. roseum) produced zearalenone. Production occurred by the wild but not the appressed cultural type. Zearalenone production by F. tricinctum was confirmed by a mouse bioassay.     

中国的膨孢组镰孢菌(英文)

膨孢组镰孢菌Fusarium在自然界中广泛分布。该组包括4个种:木贼镰孢菌F.equiseti,藨草镰孢菌F.scirpi,长脚镰孢菌F.longipes和紧致镰孢菌F.compactum。这4个种均产生腹背不平行弯曲的大孢子。分离获得并描述了其中的3个种。木贼镰孢菌F.equiseti是镰孢菌中最常见的种之一,它产生典型的腹背不平行弯曲的大孢子,大孢子的顶细胞和足跟状基细胞明显伸长,菌落因缺乏红色素而呈黄褐色。藨草镰孢菌F.scirpi是比较少见的种类,它的典型特征是在典型的十字形产孢细胞上产生大量的小型分生孢子。由于它在PDA培养基上容易发生小孢子缺乏型的变异,因此,常常被错误地鉴定为木贼镰孢菌F.equiseti。长脚镰孢菌F.longipes的大孢子最容易与其他种的大孢子区分,它的顶细胞和基细胞均极度延长。当长脚镰孢菌F.longipes菌落因为变异而失去产生红色素的能力时,也容易与木贼镰孢菌F.equiseti混淆。基于该组大孢子的典型特征,作者将锐顶镰孢菌F.acuminatum排除在该组之外。