Spotting of tomato fruits caused by Botrytis cinerea

Botrytis spot or ghost spot on tomato fruits occurs after penetration of germ tubes ofB. cinerea into epidermal cells. A few days after the penetration a halo appears around the infected necrotic cells. These symptoms can be reproduced by inoculating young fruits with a few dry conidia. When many conidia alight on the epidermis of the fruit, scab-like symptoms develop, while under conditions of high humidity, blisters can be formed on the fruit surface before the fungus spreads through the fruit parenchyma. Under conditions of low humidity, necrotic areas are formed.In the necrotic cells, developed after inoculation with many or with a few conidia, no mycelium could be found by the histological methods so far used. However,B. cinera can be reisolated, implying that theBotrytis spot is a latent infection by the fungus. No renewed growth takes place when the fruit is fully ripe.Samenvatting Botrytis-stip op tomatevruchten ontstaat na binnendringen van kiembuizen vanB. cinerea in epidermiscellen van een jonge vrucht. Enkele dagen na de infectie treden celdelingen op in het onderliggende parenchymweefsel. De geïnfecteerde cel en enkele aangrenzende cellen sterven af, terwijl rondom dit necrotische plekje een zilverwit gekleurde ring ontstaat. Worden veel conidiën bijeen op een vruchtwand gebracht, dan krijgt de epidermis binnen 24 uur een schurftig uiterlijk. Blijft de luchtvochtigheid na de inoculatie hoog, dan kunnen daarentegen kleinere en grotere blaasjes in de vruchtwand ontstaan. Deze barsten na enkele dagen open, terwojl mycelium zich door de vrucht verbreidt. Daalt de luchtvochtigheid circa 16 uur na de inoculatie, dan blijft de aantasting beperkt tot de epidermis. Hoewel in het necrotische weefsel geen mycelium vanB. cinerea kon worden aangetoond, blijkt herisolatie van de schimmel gemakkelijk te zijn. Ook uitBotrytis-stippen van uit de praktijk afkomstige vruchten kanB. cinerea geïsoleerd worden. Dit betekent, dat het hier om een latente infectie gaat, waarbij evenwel geen hernieuwde groei plaats vindt als de vrucht geheel rijp is.     

黄姜主要害虫--蛴螬的发生为害及防治技术

黄姜俗称“火头根” ,属盾叶薯蓣 ,是我国特有种。黄姜浑身是宝 ,我国利用黄姜根茎中皂甙元 (皂素) ,可合成 3大类 (皮质激素、性激素、孕激素 ) ,近2 0 0个产品系列 ,是生产甾体激素类药物最理想的物质 ,世界上 90 %的激素是利用其合成的 ,因此 ,被国家医药界誉为“药用黄金”。郧西县地处秦巴小区 ,是全国黄姜高产高含地区的中心 ,历史上曾形成庞大的野生黄姜资源带。1 9 87年开始进行大面积“野转家”栽培并获得成功 ,至今已发展到 1万hm2 以上 ,被农业部农业特产委员授予“全国黄姜之乡”。在栽培过程中 ,由于连年重茬及姜农们忽略了蛴…     

Gray mold of pearl lupine caused by <Emphasis Type="Italic">Botrytis cinerea</Emphasis>

Severe blight of stems, leaves and pods caused by Botrytis cinerea was found on pearl lupine (Lupinus mutabilis), a legume crop, grown in Kagawa Prefecture, Japan, in March–June 1996–2002. This disease was named “gray mold of pearl lupine” as a new disease. One of the fungal isolates obtained in this study was deposited in Genebank, National Institute of Agrobiological Sciences as accession MAFF238557.     

Effect of microclimate and nutrients on development of cucumber gray mold (Botrytis cinerea)

Infection of young parthenocarpic cucumber fruits byBotrytis cinerea begins in the petals. Removing petals or washing nutrients from the flower significantly reduced infection. Germination of conidia occurred at relative humidity (r.h.) above 92%, but when water deposition on artificial surfaces was prevented, germination did not occur even at 98% r.h. Germination of conidia on petals is promoted by deposition of an aqueous film not visible on the petal surface by the bare eye (but demonstrable by CoCl₂). Provided there is a film of water on the surface of the host, germination and the infection process occur at a wide range of temperatures up to 25 °C. Pre-exposure of cucumber plants at temperatures as high as 30 °C or as low as 8 °C, prior to their infection and incubation under conditions conducive to gray mold, resulted in greater severity of the disease on young fruits or leaves as compared with plants previously incubated at 10-25 °C. The relevance of these results to cultural control of gray mold is discussed.     

Programming applications of dicarboximides to control bunch rot of grapes caused by Botrytis cinerea

When grapevine plants in a glasshouse were artificially inoculated with Botrytis cinerea and then treated with dicarboximides at different stages of bunch development, treatment at 80% cap-fall, with or without treatment before bunch closure, gave significantly better control than treatment at 3 weeks before harvest. In field trials, early applications of procymidone reduced natural infection by B. cinerea better than late applications. Spray application at pre-bloom followed by a second application during bloom is recommended. Procymidone, vmclozolin and iprodione at 1 g/l were significantly more effective in controlling natural infection than dichlozolinate, benomyl, captan, chlorothalonil and copper oxychloride.     

Botrytis pseudocinerea, a new cryptic species causing gray mold in French vineyards in sympatry with Botrytis cinerea

Botrytis cinerea is a major crop pathogen infesting >220 hosts worldwide. A cryptic species has been identified in some French populations but the new species, B. pseudocinerea, has not been fully delimited and established. The aim of this study was to distinguish between the two species, using phylogenetic, biological, morphological, and ecological criteria. Multiple gene genealogies confirmed that the two species belonged to different, well-supported phylogenetic clades. None of the morphological criteria tested (spore size, germination rate, or mycelial growth) was able to discriminate between these two species. Sexual crosses between individuals from the same species and different species were carried out. Only crosses between individuals from the same species were successful. Moreover, population genetics analysis revealed a high level of diversity within each species and a lack of gene flow between them. Finally, a population survey over time showed that B. cinerea was the predominant species but that B. pseudocinerea was more abundant in spring, on floral debris. This observation could not be explained by temperature adaptation in tests carried out in vitro or by aggressiveness on tomato or bean leaves. This study clearly establishes that B. cinerea and B. pseudocinerea constitute a complex of two cryptic species living in sympatry on several hosts, including grapevine and blackberry. We propose several biological or molecular tools for unambiguous differentiation between the two species. B. pseudocinerea probably makes a negligible contribution to gray mold epidemics on grapevine. This new species has been deposited in the MycoBank international database.     

Occurrence of postharvest gray mold rot of sweet cherry due to Botrytis cinerea in Korea

Journal of Plant Diseases and Protection - In May 2016, we observed gray mold rot symptoms on harvested and refrigerated cherry fruit in Gangneung, Gangwon Province, Korea. The symptoms included...     

Infection of plum and nectarine flowers by Botrytis cinerea

The ability of Botrytis cinerea to infect plum and nectarine flowers was studied in moist chambers and in the orchard. Within 36 h of inoculation, the pathogen penetrated and colonized the stamens, styles and petals on shoots placed in moist chambers, causing blossom blight. Similar lesion development was observed following inoculation with dry and wet conidia, Hyphae were usually distorted in stylar tissue, but grew normally in petals and filaments. Growth of the fungus through filaments into the sepals or floral tubes, or through the transmitting tissue of the style into the ovary, was never observed. Symptoms of blossom blight were not observed on inoculated shoots in the orchard. The floral tube, bearing the sepals and stamens, dehisced within 14 days of fruit set and infected floral parts did not remain attached to young developing fruit. No relation was found between post-harvest decay and flower infection. Losses following post-harvest decay might have been caused by direct penetration of ripening fruit and not by flower infection. The importance of infected floral parts as a source of secondary inoculum on ripening fruit is discussed.     

Virulence factors of Botrytis cinerea

Botrytis cinerea is responsible for gray mold disease in more than 200 host plant species. The infection of host plants is mediated by numerous extracellular enzymes, proteins and metabolites. Each of these compounds may play a role in different stages of the infection process. Cell wall-degrading enzymes may facilitate the penetration into the host surface, while toxins, oxalic acid and reactive oxygen species may contribute to killing of the host cells. Cell wall-degrading enzymes contribute to the conversion of host tissue into fungal biomass. On the other hand, B. cinerea infection induces biosynthesis of phytoalexins. Therefore, the ability to overcome a wide spectrum of phytoalexins contributes to the pathogenicity of the fungus with a broad host range. The cloning of the corresponding genes has facilitated studies on gene expression and targeted mutagenesis. This review gives an overview of the research performed on virulence factors that play the roles in pathogenesis.     

深绿木霉蛋白质TraT2A诱导兰州百合抗灰霉病的作用

采用生长速率法和活体试验法分别测定了深绿木霉Trichoderma atroviride蛋白质Tra T2A对兰州百合灰霉菌的抑制作用和诱导抗病效果及持效期。结果表明TraT2A高浓度(5×液)具有较高的抑制作用,抑制率为47.44%,低浓度(100×液)具有较高的诱导抗病作用,其诱导效果可达55.89%;TraT2A 100×液处理兰州百合植株3 d后挑战接种灰霉菌,分别于0、1、3和5 d对兰州百合叶片中的PAL、PPO、POD和SOD酶活性及丙二醛、叶绿素含量变化进行了测定。发现TraT2A诱导处理后可提高百合叶片中与抗病性相关的防御酶PAL、PPO、POD、SOD活性和叶绿素含量,降低丙二醛的含量;在接种后1、3和5 d时,4种酶活性和叶绿素含量显著高于对照,丙二醛含量则低于对照,4种酶活性在第5 d时均达到最大值,PAL、PPO、POD和SOD分别是对照的1.47、2.28、1.36和1.49倍;在接种后1、3和5 d时,叶绿素含量分别比对照高10.13、12.05和6.05 mg/g;丙二醛含量仅为对照的0.68、0.40和0.51倍;TraT2A防治百合灰霉病的持效期为7 d,高于阿泰灵和速克灵的持效期。     

Biosuppression of Botrytis cinerea in grapes

There is increasing interest in the use of biological control agents (BCAs) and plant resistance stimulants to suppress botrytis bunch rot in grapes, caused by Botrytis cinerea . Numerous different filamentous fungi, bacteria and yeasts have been selected as potential BCAs for control of grey mould based upon demonstrated antagonism towards B. cinerea. Biological suppression of the pathogen arises via competition for nutrients and space, the production of inhibitory metabolites and/or parasitism. Preformed and inducible grapevine defence mechanisms also contribute to disease suppression by preventing or delaying pathogenic infection. Furthermore, various biotic and abiotic agents can stimulate grapevine defence mechanisms and so elevate resistance to B. cinerea infection. Biosuppression of B. cinerea in vineyards, using BCAs and resistance stimulants, has been inconsistent when compared with that observed in controlled glasshouse or laboratory conditions. This may be attributable, in part, to the innate variability of the field environment. Research to improve field efficacy has focused on formulation improvement, the use of BCA mixtures and combinational approaches involving BCAs and plant resistance stimulants with complementary modes of action.     

Expression of an oxalate oxidase gene in tomato and severity of disease caused by Botrytis cinerea and Sclerotinia sclerotiorum

A cDNA clone of wheat oxalate oxidase (OxO) under the control of the constitutive CAMV 35S promotor was expressed in tomato plants by Agrobacterium -mediated transformation. Twenty-six transgenic tomato lines were obtained and analysed. PCR experiments confirmed the incorporation of the OxO gene in all tested tomato lines. The transgenic tomato plants expressed a 124-kDa protein showing OxO activity, and were able to convert different oxalic acid (OA) concentrations in vitro . In a detached leaf assay, most of the transgenic lines showed reduced disease symptoms compared with controls, following inoculation with Botrytis cinerea . In addition, leaves of the line T15 showed a marked reduction in symptoms compared with the control following inoculation with Sclerotinia sclerotiorum .     

Electrophoretic karyotype analysis of Botrytis cinerea

The karyotypes of five strains ofBotrytis cinerea were analysed by pulsed field gel electrophoresis (PFGE). None of the five chromosome patterns were identical and all five strains contained one or several minichromosomes of variable length. Considering that some of the chromosomal bands represent unresolved doublets, the total genome size of the five strains was estimated to vary between at least 33.9 and 39.7 megabasepairs (Mbp). Hybridization of blots of pulsed field gels with rDNA and ß-tubulin probes revealed that these hybridize with the same chromosomal band. Chromosome-specific probes were isolated hybridizing to chromosomal bands 9 and 11 of strain SAS56. The latter two probes hybridized to only two of the five strains tested. The results are discussed in relation to the genome plasticity and variability of filamentous fungi.     

Infection of flowers and fruits of red raspberry by Botrytis cinerea

The frequency and site of symptomless infection of flower buds, flowers, and fruits of red raspberry by Botrytis cinerea was studied using surface-disinfestation and culture techniques. Flower buds were rarely infected but open flowers were rapidly colonized and necrotic stamens and styles were an important source of infection for the developing fruit. The receptacle tissue within the drupelet cluster cavity was mostly sterile. Dichlofluanid sprays reduced symptomless infection of fruits and were more effective when applied early. Post-harvest rot tests indicated that incidence of grey mould was not related to symptomless infection unless fruits were surface-disinfested before subjecting to the rotting test.     

中药丁香提取物对番茄灰霉病菌抑制作用及生防效果

 试验测定了中药丁香的甲醇提取物对番茄灰霉病菌室内抑菌作用和对番茄灰霉病的温室防治作用。室内抑菌试验采用菌丝干重法测试结果表明,提取物在20 000μg/mL和10 000 μg/mL两个浓度下对灰霉病菌菌丝生长的抑制作用均达到了80%以上,5 000μg/mL浓度下抑制作用迅速下降到35.37%。在抑制分生孢子产生的测试中,浓度为10 000μg/mL的处理完全抑制了分生孢子的产生,浓度为5 000μg/mL的处理也表现出显著的抑制产孢作用,抑制率达到85.40%,而进一步稀释的处理则没有表现出显著抑制作用。采用生长速率法测试了丁香提取物对番茄灰霉病菌菌丝生长的抑制中浓度,结果表明其抑制中浓度为3 292.38μg/mL。在温室盆栽试验中,浓度为20 000μg/mL的处理对番茄灰霉病的保护防治效果达到86.45%,与化学药剂处理达到无显著差异,浓度为10 000μg/mL的处理在保护作用测试中也表现出了显著的防治效果。     

Hypovirulence and Double-Stranded RNA in Botrytis cinerea

ABSTRACT Twenty-one strains of Botrytis cinerea isolated from 13 species of plants grown in China were compared for pathogenicity on Brassica napus, mycelial growth on potato dextrose agar, and presence of double-stranded (ds)RNA. The results showed that the strain CanBc-1 was severely debilitated in pathogenicity and mycelial growth, compared with the 20 virulent strains. A dsRNA of approximately 3.0 kb in length was detected in CanBc-1 and 4 hypovirulent single-conidium (SC) isolates of CanBc-1, but was not detected in the 20 virulent strains of B. cinerea and 4 virulent SC isolates of CanBc-1. Results of the horizontal transmission experiment showed that the hypovirulent trait of CanBc-1 was transmissible and the 3.0-kb dsRNA was involved in the transmission of hypovirulence. Analysis of a 920-bp cDNA sequence generated from the 3.0-kb dsRNA of CanBc-1 indicated that the dsRNA element was a mycovirus, designated as B. cinerea debilitation-related virus (BcDRV). Further analyses showed that BcDRV is closely related to Ophiostoma mitovirus 3b infecting O. novo-ulmi, the causal agent of Dutch elm disease. Mitochondria and cytoplasm in hyphal cells of CanBc-1 became degenerated, compared with the virulent isolate CanBc-1c-66 of B cinerea. This is the first report on the occurrence of Mitovirus-associated hypovirulence in B. cinerea.     

Biological Control of Botrytis cinerea by Volatiles of 'Isabella' Grapes

ABSTRACT The effect of volatiles from cv. Isabella (Vitis labrusca) on the growth of Botrytis cinerea was tested in vitro and in situ, in the latter case on 'Roditis' grapes (V. vinifera), at various temperatures. The goal of the research was to determine whether the volatiles emitted by Isabella grapes could be effective biocontrol agents of Botrytis cinerea. The closed Mariotte system was used as a bioassay method to analyze quantitatively the biological action of these volatiles on fungal growth and disease development. The in vitro experiments revealed the inhibitory action of the Isabella volatiles on the sporulation and sclerotia formation of the fungus, as well as the stimulating action of the Roditis volatiles on the sporulation of the fungus. The in situ study confirmed the antifungal action of the Isabella volatiles as they reduced the inoculum and pathogenicity of B. cinerea. The antibiotic action was more pronounced at 21 degrees C. The study indicates that Isabella volatiles act as biocontrol agents of B. cinerea.     

灰霉菌的抗药性与适合度测定

室内监测了北京、沈阳、保定等地区番茄灰霉菌 (Botrytis cinerea)对不同杀菌剂的抗药性 ,发现抗多菌灵菌株占监测总数的 74 .6 7% ,抗乙霉威菌株占 2 5.82 % ,还监测到 3株抗多菌灵、乙霉威菌株——即双抗菌株 ;利用菌落直径法和番茄叶片法测定了 3种抗药类型的番茄灰霉菌在离体和活体条件下的适合度 ,结果表明 ,不同抗药类型菌株在生长速率、致病力、繁殖力等方面差异不明显。