Effects of elicitors on growth of adventitious roots and contents of secondary metabolites in Tripterygium wilfordii Hook. f / 生物工程学报

To study the effects of the extract of fungal elicitor, AgNO3, MeJA and yeast on the growth and content of secondary metabolites of adventitious roots in Tripterygium wilfordii. The above elicitors were supplemented to the medium, the growth and the content of secondary metabolites were measured. When the medium was supplemented with the elicitor Glomerella cingulata or Collectotrichum gloeosporioides, the content of triptolide was increased by 2.24 and 1.93-fold, the alkaloids content was increased by 2.02 and 2.07-fold, respectively. The optimal concentration of G. cingulata was 50 μg/mL for accumulation of triptolide, alkaloids and for the growth of adventitious roots. AgNO3 inhibited the growth of adventitious roots and the accumulation of the alkaloids, whereas it (at 25 μmol/L) increased the accumulation of triptolide by 1.71-fold compared to the control. The growth of adventitious roots, the contents of triptolide and alkaloids were increased 1.04, 1.64 and 2.12-folds, respectively when MeJA was at 50 μmol/L. When the concentration of yeast reached 2 g/L, the content of triptolide increased 1.48-folds. This research demonstrated that supplementation of AgNO3 and yeast enhanced the biosynthesis of triptolide in adventitious roots and the synergism of G. cingulata and MeJA could promote the biosynthesis of both triptolide and alkaloids.

Occurrence of Anthracnose on Highbush Blueberry Caused by Colletotrichum Species in Korea

A total of 82 isolates of Colletotrichum species were obtained from anthracnose symptoms of highbush blueberry trees grown in the Gochang area of Korea during a disease survey in 2008. Out of the isolates, 75 were identified as Colletotrichum gloeosporioides and the others as C. acutatum based on their morphological and cultural characteristics. Twenty six of C. gloeosporioides isolates produced their teleomorph Glomerella cingulata in PDA culture. Three isolates of each C. gloeosporioides and C. acutatum caused anthracnose symptoms on the leaves by artificial inoculation, which were similar to what was observed in the orchards. Previously in Korea, only C. gloeosporioides has been reported as causing anthracnose in blueberries. This is the first report that C. acutatum causes anthracnose in the highbush blueberry in Korea.

Antimicrobial efficacy of secondary metabolites from Glomerella cingulata

Fungi are known to produce a vast array of secondary metabolites that are gaining importance for their biotechnological applications. Early reports suggest that G. cingulata has the capability to transform many compounds by various enzymatic actions. Therefore, the focus of this study was to determine the antibacterial and antifungal activity of crude ethyl acetate extract of G. cingulata using agar cup bioassay method. Crude extract of G. cingulata exhibited remarkable antifungal activity against Rhizopus oryzae, Chrysoporium tropicum and Beauveria bassiana but no antifungal activity was found against Alternaria tenuissima and Aspergillus niger at any concentrations. The crude extract presented no antibacterial activity against Gram positive and Gram negative bacteria at any concentration.

Fungos são conhecidos produtores de uma vasta coleção de metabólitos secundários que vem mostrando importância crescente na sua aplicação biotecnológica. Publicações anteriores sugerem que G. cingulata tem a capacidade de transformar vários componentes por diferentes ações enzimáticas. Logo, o foco deste estudo foi determinar a atividade antibacteriana e antifúngica do extrato bruto de G. cingulata obtido por acetato de etila utilizando-se um método envolvendo bloco de agar. O extrato bruto de G. cingulata demonstrou marcante atividade antifungica contra Rhizopus oryzae, Chrysoporium tropicum e Beauveria bassiana entretanto, não foi possível detectar, em nenhuma concentração, atividade antifungica contra Alternaria tenuissima e Aspergillus niger. O mesmo extrato não apresentou atividade antibacteriana, em nenhuma concentração, contra bactérias Gram negativa e positiva.

Identification of Glomerella cingulata f. sp phaseoli recombinants by RAPD markers

We examined the capacity of strains of Glomerella cin-gulata f. sp phaseoli fungus (Colletotrichum lindemuthianum sexual stage) to form recombinants, using random amplified polymorphic DNA (RAPD). Crosses of all possible combinations between strains 40, 42, 20, 21, 22, 23, 24, 25, and 26 were made on Petri dishes using M3 culture medium. The 42 x 21 cross produced the largest number of perithecia and five asci; the respective ascospores were isolated. RAPD analysis was performed on the parents and descendants. The 62 polymorphic RAPD bands obtained were used to assess the genetic similarity using the method of Sorence and Dice and clustering analysis in the form of a dendrogram by the UPGMA method. The RAPD markers allowed identification of recombinants from the cross between strains 42 and 21 of G. cingulata f. sp phaseoli and 40 ascospores presented 63 and 49% genetic similarity with parents 2 (strain 42) and 1 (strain 21), respectively.

Active changes of lignification-related enzymes in pepper response to Glomus intraradices and/or Phytophthora capsici / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

The activities of enzymes responsible for lignification in pepper, pre-inoculation with arbuscular mycorrhizal (AM) fungus of Glomus intraradices and/or infection with pathogenic strain of Phytophthora capsici, and the biological control effect of G. intraradices on Phytophthora blight in pepper were investigated. The experiment was carried out with four treatments: (1) plants pre-inoculated with G. intraradices (Gi), (2) plants pre-inoculated with G. intraradices and then infected with P. capsici (Gi+Pc), (3) plants infected with P. capsici (Pc), and (4) plants without any of the two microorganisms (C). Mycorrhizal colonization rate was reduced by about 10% in pathogen challenged plants. Root mortality caused by infection of P. capsici was completely eliminated by pre-inoculation with antagonistic G. intraradices. On the ninth day after pathogen infection, Peroxidase (POD) activity increased by 116.9% in Pc-treated roots but by only 21.2% in Gi+Pc-treated roots, compared with the control, respectively. Polyphenol oxidase (PPO) and Phenylalanine ammonia-lyase (PAL) activities gradually increased during the first 3 d and dramatically decreased in Pc-treated roots but slightly decreased in Gi+Pc-treated roots, respectively. On the ninth day after pathogen infection, PPO and PAL decreased by 62.8% and 73.9% in Pc-treated roots but by only 19.8% and 19.5% in Gi+Pc-treated roots, compared with the control, respectively. Three major POD isozymes (45,000, 53,000 and 114,000) were present in Pc-treated roots, while two major bands (53,000 and 114,000) and one minor band (45,000) were present in spectra of Gi+Pc-treated roots, the 45,000 POD isozyme was significantly suppressed by G. intraradices, suggesting that the 45,000 POD isozyme was induced by the pathogen infection but not induced by the antagonistic G. intraradices. A 60,000 PPO isozyme was induced in Pc-treated roots but not induced in Gi+Pc-treated roots. All these results showed the inoculation of antagonistic G. intraradices alleviates root mortality, activates changes of lignification-related enzymes and induces some of the isozymes in pepper plants infected by P. capsici. The results suggested that G. intraradices is a potentially effective protection agent against P. capsici.

Antracnosis en plántulas de macadamia: causada por glomerella cingulata / Antracnosis in macadamia plantlets caused by glomerella cingulata

La nuez de macadamia es considerada una de las mejores y más finas del mundo. No contiene colesterol y los niveles de sodio y grasas saturadas son bajos. Sus aceites naturales contienen 80 por ciento de grasas monoinsaturadas, el valor más alto en los aceites conocidos. Varias especies del género Macadamia (Proteaceae) producen nueces comestibles, pero sólo M.integrifolia y M.tetraphylla, son comercialmente importantes. Ambas son originarias de Australia, siendo M.integrifolia la que mejor se adapta al trópico. Desde su introducción en Venezuela el cultivo ha sido afectado por diversos factores, siendo uno de ellos una enfermedad foliar que durante el 2001 destruyó muchas plántulas de viveros, localizados en distintas zonas del Estado Mérida. Las hojas enfermas presentaban tejidos muertos en la punta y los bordes, en forma de grandes manchas irregulares de color marrón oscuro. Algunas hojas estaban completamente muertas y otras sólo tenían pequeñas manchas de color marrón oscuro. Se investigó la identidad del microorganismo causante de estos síntomas, que resultó ser Glomerella cingulata, teleomorfo de Colletotrichum gloeosporioides, patógeno ampliamente conocido en las regiones tropicales donde ataca diversos frutales. El hongo formó conidiomas y ascomas en medio papa-dextrosa agar, y cuando fue inoculado sólo infectó hojas jóvenes de M.integrifolia. Este es el primer reporte de G.cingulata infectando plántulas de macadamia en Venezuela

Ultrastructural aspects in perithecia hyphae septal pores of "Glomerella cingulata" sp. "phaseoli"

"Glomerella cingulata" (Stonem.) Spauld & Schrenck f. sp. "phaseoli", better known in its anamorphic state "Colletotrichum lindemuthianum" (Sacc. & Magn.) Briosi & Cav., is a casual agent of anthracnose in beans (Phaseolus vulgaris L.). Ultrastructural aspects of the perithecial hyphae of this pathogen were studied. The perithecia hyphae septal pores were found either plugged by a vesicular or unplugged. Some perithecia hyphae septa presented no pore. The Woronin bodies, close to the septal pores, appeared as globose structures wich were more electron dense than the occlusions plugging the septal pore.