Effects of ozone treatment on the quality of kiwifruit during postharvest storage affected by Botrytis cinerea and Penicillium expansum

The objective was to reveal the effects of ozone treatment on quality maintenance and resistance to Botrytis cinerea and Penicillium expansum in kiwifruit during postharvest storage. Kiwifruits were treated with 79.44 ppm gaseous ozone for 1 hr once a day for 7 day at 0°C to determine the effects of ozone treatment on the quality and disease incidence caused by B. cinerea and P. expansum in vivo and the growth of B. cinerea and P. expansum in vitro. Ozone treatment significantly reduced the disease incidence of kiwifruit and inhibited the mycelial development and spore germination of B. cinerea and P. expansum. High levels of fruit firmness and titratable acidity were maintained in the ozone‐treated kiwifruit, and the activities of the defence‐related enzymes were remarkably enhanced. Therefore, ozone treatment may be an effective method to maintain the quality of kiwifruit and control its decay during postharvest storage.     

The Influence of o-hydroxyethylorutin on Botrytis cinerea Oxidant–Antioxidant Activity

The objective of this study was to evaluate the effects of o‐hydroxyethylorutin on Botrytis cinerea mycelium growth and metabolism. Hydrogen peroxide concentration, superoxide dismutase, catalase and peroxidase activities were compared in the pathogens’ mycelium grown on control and o‐hydroxyethylorutin containing medium. Transfer of B. cinerea mycelium to medium supplemented with 5 mm o‐hydroxyethylorutin resulted in a large decrease in catalase activity. No changes in mycelium growth, hydrogen peroxide concentration and superoxide dismutase activity were observed. Guaiacol and ascorbate peroxidases were not detected in mycelia. The data are consistent with previous findings that o‐hydroxyethylorutin treatment of tomato plants restricts the development of B. cinerea infection due to the induction of higher active oxygen species (AOS) generation in plants by this compound. Being poor in catalase, the pathogen may not be able to cope with increasing AOS formation. The results indicate that catalase is an infective agent of B. cinerea.     

A constitutive PR-1::luciferase expression screen identifies Arabidopsis mutants with differential disease resistance to both biotrophic and necrotrophic pathogens

A complex signal transduction network involving salicylic acid, jasmonic acid and ethylene underlies disease resistance in Arabidopsis. To understand this defence signalling network further, we identified mutants that expressed the marker gene PR-1::luciferase in the absence of pathogen infection. These cir mutants all display constitutive expression of a suite of defence-related genes but exhibit different disease resistance profiles to two biotrophic pathogens, Pseudomonas syringae pv. tomato and Peronospora parasitica NOCO2, and the necrotrophic pathogen Botrytis cinerea. We further characterized cir3, which displays enhanced resistance only to the necrotrophic pathogen. Cir3-mediated resistance to B. cinerea is dependent on accumulated salicylic acid and a functional EIN2 protein.     

β-Glucosidase from Botrytis cinerea: Its Relation to the Pathogenicity of This Fungus

Cellulolytic enzyme activities in 11 strains of B. cinerea and their pathogenicity against apples, grapes, and lettuce were tested. A positive correlation was found between the β-glucosidase activity of B. cinerea cultured in PYA-medium and the pathogenicity, as expressed in the area of lesions. Further, this correlation was found to hold for the β-glucosidase activity of the apple fruit lesion caused by B. cinerea.

Since it was suggested that pathogenicity of B. cinerea depended on its β-glucosidase activity, the β-glucosidase was purified and characterized. The enzyme had its optimum pH at 3.0, and was very stable in a wide range of pH. These properties were extremely advantageous for B. cinerea to infect the apple fruit.     

东方蜜蜂微孢子虫侵染意大利蜜蜂工蜂过程的nce-miR-23928及其靶基因表达谱

【背景】东方蜜蜂微孢子虫(Nosema ceranae)专性侵染成年蜜蜂中肠上皮细胞而导致的微孢子虫病给养蜂业造成严重损失。【目的】检测东方蜜蜂微孢子虫nce-miR-23928及其靶基因在侵染意大利蜜蜂(Apis mellifera ligustica)工蜂过程的表达谱,为深入探究nce-miR-23928在东方蜜蜂微孢子虫侵染中的功能及调控机制提供依据。【方法】通过RNAhybrid、miRanda和TargetScan软件预测nce-miR-23928的靶基因。使用BLAST工具将上述靶基因比对到基因本体论(geneontology,GO)、京都基因和基因组百科全书(Kyoto encyclopedia of genes and genomes, KEGG)、Nr和Swiss-Prot数据库以获得相应注释。采用实时荧光定量PCR(realtimequantitativePCR,RT-qPCR)技术检测nce-miR-23928及其靶基因在东方蜜蜂微孢子虫侵染意蜂工蜂过程中的相对表达量。【结果】相较于接种后1 d (1 day post infection, 1 dpi),nce-...     

Oviposition preference and larval performance of Epiphyas postvittana (Lepidoptera: Tortricidae) on Botrytis cinerea (Helotiales: Sclerotiniaceae) infected berries of Vitis vinifera (Vitales: Vitaceae)

In this paper we tested the behavior of gravid Epiphyas postvittana in selecting the most‐appropriate site for oviposition thus benefitting offspring performance. Our hypothesis was built on Jaenike's preference–performance hypothesis (also referred to as the “mother‐knows‐the‐best” hypothesis). To test this, we used the interacting Epiphyas postvittana, its host Vitis vinifera, and the pathogenic microbe Botrytis cinerea system. Populations of E. postvittana and B. cinerea often exist concurrently on V. vinifera in Australasia and their interaction and mutual influence are currently being explored, although the suggestion presently is that the relationship between E. postvittana and B. cinerea is mutualistic. We tested the effect of volatiles from B. cinerea‐infected berries and uninfected (control) berries of V. vinifera on the oviposition behavior of E. postvittana. We also characterized the effects of B. cinerea infection on the berries of V. vinifera on the growth and development of E. postvittana. Contrary to the preference–performance hypothesis, oviposition choices made by gravid E. postvittana did not result in the best offspring survival, development, and performance. The preference for oviposition by E. postvittana was strongly influenced by the olfactory and tactile cues. She laid fewer eggs on B. cinerea‐infected berries compared to uninfected berries of V. vinifera. The larvae of E. postvittana showed no preference to uninfected berries of V. vinifera. The larvae fed on B. cinerea‐infected berries of V. vinifera showing greater survival rate, shorter time to pupation, greater pupal mass, and on becoming adults they laid more numbers of eggs than the larvae that were enabled to feed on uninfected berries. The larvae of E. postvittana transport the conidia of B. cinerea and transmit grey‐mould disease to uninfected berries of V. vinifera.     

Inhibition of Botrytis cinerea by Epirodin: A Secondary Metabolite from New Zealand Isolates of Epicoccum nigrum

Many isolates of the saprophytic fungus Epicoccum nigrum produce yellow compounds that diffuse readily into culture media. Historically, two such compounds have been identified; flavipin and epirodin both reported to have antimicrobial properties. Preliminary studies on 280 New Zealand isolates of E. nigrum confirmed that all but two produced a yellow, intensely pigmented substance in sufficient amounts to inhibit the germination of Botrytis cinerea conidia. The compound produced by the inhibitory isolates is epirodin, a polyene antibiotic. Five representative E. nigrum isolates were selected for further investigation. Two of these produced relatively large amounts of epirodin and, in a diffusible metabolite assay, reduced germination of B. cinerea conidia by up to 94%. Another isolate produced a trace amount of epirodin and had no effect on the germination of B. cinerea conidia or on germ tube morphology. The two remaining isolates produced intermediate amounts of epirodin and were only moderately inhibitory to the germination of B. cinerea conidia and to germ tube morphology. In slide dual‐culture experiments, epirodin appeared to concentrate in conidia and mycelia of B. cinerea. In acid conditions, as on dual‐culture slides of E. nigrum and B. cinerea, the yellow‐coloured epirodin underwent a hypsochromic shift, changing colour to become red. The relationship between epirodin production and the suppression of Botrytis growth and development was further investigated using necrotic kiwifruit leaf discs. The E. nigrum isolate that produced the greatest amount of epirodin almost completely inhibited the growth and development of B. cinerea on the leaf discs. In contrast, the efficacy of E. nigrum isolates which produced less epirodin ranged from 78% to just 23%. This is the first report of epirodin production by New Zealand isolates of E. nigrum, and we conclude that isolates that produce high concentrations of epirodin may have potential for plant disease control.