Species diversity of and toxin production by Gibberella fujikuroi species complex strains isolated from native prairie grasses in Kansas

Fusarium species from agricultural crops have been well studied with respect to toxin production and genetic diversity, while similar studies of communities from nonagricultural plants are much more limited. We examined 72 Fusarium isolates from a native North American tallgrass prairie and found that Gibberella intermedia (Fusarium proliferatum), Gibberella moniliformis (Fusarium verticillioides), and Gibberella konza (Fusarium konzum) dominated. Gibberella thapsina (Fusarium thapsinum) and Gibberella subglutinans (Fusarium subglutinans) also were recovered, as were seven isolates that could not be assigned to any previously described species on the basis of either morphological or molecular characters. In general, isolates from the prairie grasses produced the same toxins in quantities similar to those produced by isolates of the same species recovered from agricultural hosts. The G. konza isolates produce little or no fumonisins (up to 120 micro g/g by one strain), and variable but generally low to moderate amounts of beauvericin (4 to 320 micro g/g) and fusaproliferin (50 to 540 micro g/g). Toxicity to Artemia salina larvae within most species was correlated with the concentration of either beauvericin or fusaproliferin produced. Organic isolates from some cultures of G. moniliformis were highly toxic towards A. salina even though they produced little, if any, beauvericin or fusaproliferin. Thus, additional potentially toxigenic compounds may be synthesized by G. moniliformis strains isolated from prairie grasses. The Fusarium community from these grasses appears to contain some species not found in surrounding agricultural communities, including some that probably are undescribed, and could be capable of serving as a reservoir for strains of potential agricultural importance.     

Molecular mapping of QTLs for resistance to Gibberella ear rot, in corn, caused by Fusarium graminearum.

Gibberella ear rot, caused by the fungus Fusarium graminearum Schwabe, is a serious disease of corn (Zea mays) grown in northern climates. Infected corn is lower yielding and contains toxins that are dangerous to livestock and humans. Resistance to ear rot in corn is quantitative, specific to the mode of fungal entry (silk channels or kernel wounds), and highly influenced by the environment. Evaluations of ear rot resistance are complex and subjective; and they need to be repeated over several years. All of these factors have hampered attempts to develop F. graminearum resistant corn varieties. The aim of this study was to identify molecular markers linked to the genes for resistance to Gibberella ear rot. A recombinant inbred (RI) population, produced from a cross between a Gibberella ear rot resistant line (CO387) and a susceptible line (CG62), was field-inoculated and scored for Gibberella ear rot symptoms in the F4, F6, and F7 generations. The distributions of disease scores were continuous, indicating that resistance is probably conditioned by multiple loci. A molecular linkage map, based on segregation in the F5 RI population, contained 162 markers distributed over 10 linkage groups and had a total length of 2237 cM with an average distance between markers of 13.8 cM. Composite interval mapping identified 11 quantitative trait loci (QTLs) for Gibberella ear rot resistance following silk inoculation and 18 QTLs following kernel inoculation in 4 environments that accounted for 6.7%-35% of the total phenotypic variation. Only 2 QTLs (on linkage group 7) were detected in more than 1 test for silk resistance, and only 1 QTL (on linkage group 5) was detected in more than 1 test for kernel resistance, confirming the strong influence of the environment on these traits. The majority of the favorable alleles were derived from the resistant parent (CO387). The germplasm and markers for QTLs with significant phenotypic effects may be useful for marker-assisted selection to incorporate Gibberella ear rot resistance into commercial corn cultivars.     

Complete genetic linkage maps from an interspecific cross between Fusarium circinatum and Fusarium subglutinans

The Gibberella fujikuroi complex includes many plant pathogens of agricultural crops and trees, all of which have anamorphs assigned to the genus Fusarium. In this study, an interspecific hybrid cross between Gibberella circinata and Gibberella subglutinans was used to compile a genetic linkage map. A framework map was constructed using a total of 578 AFLP markers together with the mating type (MAT-1 and MAT-2) genes and the histone (H3) gene. Twelve major linkage groups were identified (n=12). Fifty percent of the markers showed significant deviation from the expected 1:1 transmission ratio in a haploid F(1) cross (P <0.05). The transmission of the markers on the linkage map was biased towards alleles of the G. subglutinans parent, with an estimated 60% of the genome of F(1) individuals contributed by this parent. This map will serve as a powerful tool to study the genetic architecture of interspecific differentiation and pathogenicity in the two parental genomes.     

农杆菌介导的针叶树基因工程

农杆菌介导的针叶树基因工程唐巍,郭仲琛,桂耀林（中国科学院植物研究所,北京１０００４４）与传统的杂交育种相比,针叶树基因工程为在更短的时间内将具有特殊性状的基因引入有重要价值的森林树种提供了机会。基因工程在许多农作物中已获得成功．可是,这些方法在森林树种特别是在针叶树种中的应用,由于缺乏良好的转化方法和再生系统而受到严重限制。     

Gibberella konza (Fusarium konzum) sp. nov. from prairie grasses, a new species in the Gibberella fujikuroi species complex

The Gibberella fujikuroi species complex (Fusarium section Liseola and allied taxa) is composed of an increasingly large number of morphological, biological and phylogenetic species. Most of the known species in this group have been isolated from agricultural ecosystems or have been described from a small number of isolates. We sampled Fusarium communities from native prairie grasses in Kansas and recovered a large number of isolates that superficially resemble F. anthophilum. We used a combination of morphological, biological and molecular characters to describe a new species, Gibberella konza (Gibberella fujikuroi mating population I [MP-I]), from native prairie grasses in Kansas. Although female fertility for field isolates of this species appears to be low, G. konza is heterothallic, and we developed reliably female fertile mating population tester strains for this species. The F. konzum anamorph is differentiated from F. anthophilum and from other Fusarium species in section Liseola by mating compatibility, morphology, AFLP fingerprint profile and differences in β-tubulin DNA sequence.     

红豆杉细胞与赤霉菌交互诱导对红豆杉细胞紫杉醇含量的影响

在赤霉菌培养过程中加入红豆杉细胞诱导物,再用此赤霉菌诱导悬浮培养的红豆杉细胞。与未受植物来源物质作用的单向诱导相比,该交互诱导使红豆杉细胞的紫杉醇含量提高5倍,交互诱导的效果受诱导物的各类的影响,其中,诱导物是红豆杉细胞壁和赤霉菌细胞壁时,交互诱导效果最好。     

Species Diversity of and Toxin Production by Gibberella fujikuroi Species Complex Strains Isolated from Native Prairie Grasses in Kansas

Fusarium species from agricultural crops have been well studied with respect to toxin production and genetic diversity, while similar studies of communities from nonagricultural plants are much more limited. We examined 72 Fusarium isolates from a native North American tallgrass prairie and found that Gibberella intermedia (Fusarium proliferatum), Gibberella moniliformis (Fusarium verticillioides), and Gibberella konza (Fusarium konzum) dominated. Gibberella thapsina (Fusarium thapsinum) and Gibberella subglutinans (Fusarium subglutinans) also were recovered, as were seven isolates that could not be assigned to any previously described species on the basis of either morphological or molecular characters. In general, isolates from the prairie grasses produced the same toxins in quantities similar to those produced by isolates of the same species recovered from agricultural hosts. The G. konza isolates produce little or no fumonisins (up to 120 μg/g by one strain), and variable but generally low to moderate amounts of beauvericin (4 to 320 μg/g) and fusaproliferin (50 to 540 μg/g). Toxicity to Artemia salina larvae within most species was correlated with the concentration of either beauvericin or fusaproliferin produced. Organic isolates from some cultures of G. moniliformis were highly toxic towards A. salina even though they produced little, if any, beauvericin or fusaproliferin. Thus, additional potentially toxigenic compounds may be synthesized by G. moniliformis strains isolated from prairie grasses. The Fusarium community from these grasses appears to contain some species not found in surrounding agricultural communities, including some that probably are undescribed, and could be capable of serving as a reservoir for strains of potential agricultural importance.     

Description of Gibberella sacchari and neotypification of its anamorph Fusarium sacchari

We described the teleomorph of Fusarium sacchari as Gibberella sacchari, sp. nov. This species can be separated from other species of Gibberella on the basis of the longer, narrower ascospores found in G. sacchari and by sexual cross fertility. Female-fertile mating type tester strains were developed that can be used for making sexual crosses with this heterothallic fungus under laboratory conditions. The anamorph, Fusarium sacchari, was neotypified.     

赤霉菌分子生物学研究进展

过去 1 0年中 ,由于基因克隆、遗传转化等分子生物学方法与技术的应用 ,对赤霉菌中赤霉素生物合成基因的克隆、鉴定、异源表达及其表达调控等分子生物学研究取得了很大进展。现从赤霉菌的转化系统、赤霉素生物合成基因克隆、合成机理及其基因表达调控等方面的研究进展进行综述     

Structure of a New Nor-kaurenolide from Gibberella fujikuroi

A novel metabolite from Gibberella fujikuroi was isolated and its structure was elucidated as 4β,7β-dihydroxy-18-norkaurenolide (I).     

Gibberella musae (Fusarium musae) sp. nov., a recently discovered species from banana is sister to F. verticillioides

Several strains of Fusarium isolated from banana were identified previously as F. verticillioides (Sacc.) Nirenberg but described as unable to produce fumonisin. Here we report biochemical and morphological evidence, as well as multilocus phylogenetic analyses based on elongation factor (EF-1α), calmodulin, β-tubulin, and the second largest subunit of RNA polymerase II (RPB2) sequences, indicating that these isolates represent a unique lineage in the Gibberella fujikuroi species complex related to but distinct from F. verticillioides. Together with previous results of molecular studies, as well as with results of metabolite analyses, crossing experiments, pathogenicity tests and morphological characterization, these new data indicate that these strains isolated from banana represent a new species, Gibberella musae Van Hove et al. sp. nov. (anamorph: Fusarium musae Van Hove et al. sp. nov.), which is described herein.     

1株产酸碱指示剂的真菌的鉴定

采用形态学和分子生物学鉴定的方法,对1株产生酸碱指示剂的真菌进行鉴定.结果表明,该菌株的子囊壳呈球形或卵形,单生或聚生,子囊孢子双胞,无色,椭圆形,分隔处稍缢缩,无性态为串珠镶孢.通过该菌株rDNA ITS的PCR扩增和序列测定,与NCBI网站进行同源性比对分析,结果表明待测菌株与藤仓赤霉菌(Gibberella fujikuroi)同源性为100％,确定该菌株为蘑仓赤霉菌.     

alpha-Amylase production by solid state fermentation: a new practical approach to biotechnology courses

A laboratory practical experiment in Biotechnology involving the investigation of alpha-amylase production by solid state fermentation of Gibberella fujikuroi is described.     

The influence of the nitrogen source on the production of gibberellic acid in submerse cultivation ofGibberella fujikuroi

Исследовалось влияние источников азота на размеры продукции гибберелловой кислоты при глубинной культивации Gibberella fujikuroi. Опыты ставились с одним из штаммов-производителей на средах, основу которых составляла ранее разработанная среда с сахарозой и кукурузным экстрактом. Наряду с благоприятным влиянием некоторых органических азотосодержащих веществ было подтверждено и решающее влияние низких величин pH в начале ферментации, особенно выразительное для среды с дрожжевым экстрактом. Наиболее высокая продукция (400–500 μг/мл) в сравнении с первоначальной средой с кукурузным экстрактом (продукция 190–240 μг/мл) была получена на суспензиях с арашидовой или соевой мукой при работе на вращательной качалке на 8–10-й день ферментации. Влияние этих азотосодержащих питательных веществ для повышения продукции оказывается специфическим.     

Fusarium temperatum sp. nov. from maize, an emergent species closely related to Fusarium subglutinans

A large number of Fusarium isolates closely related to F. subglutinans were collected from maize in Belgium. We used a robust polyphasic approach to describe a new biological species, Fusarium temperatum, within the Gibberella fujikuroi species complex. F. temperatum can be distinguished from F. subglutinans and from other Fusarium species within the Gibberella fujikuroi species complex with AFLP fingerprint profile, differences in the translation elongation factor 1-α and β-tubulin DNA sequence and interspecies mating compatibility analyses. Intraspecies mating compatibility suggests that sexual reproduction might be common for field isolates of F. temperatum, and reliable female fertile mating population tester strains were proposed for this heterothallic species.     

Identification and heritability of fumonisin insensitivity in Zea mays

Landraces of maize (Zea mays ssp. mays) and its wild teosinte relatives (Zea mays spp. parviglumis and mexicana) were surveyed for sensitivity to fumonisin B(1), a phytotoxin produced by the maize pathogen Gibberella moniliformis. Only two of 42 Z. mays samples were highly insensitive to FB(1) (ED(50) = ca. 200 microM). The teosintes and 76% of the maize landraces were moderately or highly sensitive to FB(1) (ED(50) < or = 30 microM), which indicates that FB(1) sensitivity is likely to be an ancestral trait in Z. mays. F(1) generations derived from crosses between FB(1)-sensitive maize inbred B73 and insensitive landraces were significantly less sensitive than B73. Thus, our data indicate that FB(1)-insensitivity is a relatively rare but heritable trait in maize. We also report the sensitivity of maize to other Gibberella toxins - beauvericin, diacetoxyscirpenol, and moniliformin.     

Photoinduction of carotenoid biosynthesis in Gibberella fujikuroi

Abstract Carotenoid biosynthesis is photoinducible in Gibberella fujikuroi , an organism used in the fermentive production of the gibberellins. The light exposed needed for an appreciable response is higher than those required for other fungi, such as Fusarium aquaeductuum and Neurospora crassa , under identical conditions. Time course of the accumulation of carotenoids is very similar to that for Fusarium aquaeductuum . Growth in one of the culture media used increases the carotenoid content in the dark but does not affect photoinduction. Three mutants with enhanced carotenoid synthesis in the dark show the same response to light as the wild-type. Our results suggest that photoinduction of carotenogenesis in Gibberella fujikori is independent of the carotenoid content already present in dark-grown cultures.     

Factors affecting the production of various gibberellins during submerged cultivation ofGibberella fujikuroi

Влияние условий культивирования на образование гиббереллинов при глубиннои ферментации Gibberella fujikuroi изучали с помощью хроматографии на бумаге гибберелловой кислоты и гиббе-реллина А прямо в ферментационной среде и путем определения характера выделенных кристаллических продуктов. При благоприятных условиях применявшийся нами продуктивный щтамм способен образовать и одну только гиббелловую кислоту, и ее смесь с гиббереллином А и В обоих случаях дает сравнительно высокий выход. Из факторов, определяющих качество возникаюшего активного метаболита, наиболее выразительное влияние оказывает состав ферментационной среды, в особенности качество источника азота. Наблюдалося однако и влияние некоторых других факторов, напр., исходного pH культуры и интенсивности аэрации. Кукурузный экстракт как источник азота в ферментационной среде окзывает выразительное влияние на образование гибберелловой кислоты. В средах с суспензией соевой или арашидовой муки, в условиях, благоприьтных для получения максимальной общей продук-ции гиббереллинов, наблюдается образование смеси гибберелловой кислоты и гиббереллина А.