Purification and characterization of a 40.8-kDa cutinase in ungerminated conidia of Botrytis cinerea Pers.: Fr

Cytoplasmic soluble proteins from ungerminated conidia of Botrytis cinerea exhibited cutinase activity. A 40.8-kDa cutinase was purified to homogeneity from this crude conidial protein extract. This cutinase does not correspond either to constitutive or to induced lytic cutin enzymes already described by other authors. The possible role of this constitutive cutinase in the induction of other cutinolytic proteins in the early stages of infection of plants by B. cinerea is discussed.     

Decision-making tools for Frankliniella occidentalis management in strawberry: consideration of target markets

The western flower thrips (WFT), Frankliniella occidentalis Pergande (Thysanoptera: Thripidae), a cosmopolitan pest of many crops, is considered a major pest of low tunnel and greenhouse strawberries. The extent of damage to strawberry is unclear because different studies have produced contradictory results. Also, economic thresholds published for WFT in strawberry vary greatly, and most fail to incorporate economic factors. This study was aimed at developing a decision‐making tool for WFT management in strawberries in Israel. Toward this end, economic injury levels (EIL) and economic thresholds were calculated, based on target markets (export vs. domestic). Results indicate that serious infestation of ripe berries may cause a dull, rough appearance, and the fruit may be soft and have a reduced shelf life, rendering it unsuitable for export. Most fruit damage occurred at green and turning‐red stages of development. Two decision‐making tools were developed, one for winter, when WFT populations increase slowly but crop value is high (export market); and the second for spring, when the pest increases rapidly but crop value is low (local markets). Economic thresholds of 10 and 24 WFT/flower were calculated for winter and spring strawberries, respectively, based on direct thrips damage to fruit. This calculation does not take into account the recorded WFT damage to flowers, or its role in facilitating Botrytis cinerea fruit infection. Western flower thrips has proved only an occasional economic pest in Israeli strawberries, and no routine control measures are warranted. Furthermore, augmentative releases of Orius laevigatus or Neoseilus cucumeris against WFT are not justified in this system, because Orius colonizes strawberry fields spontaneously in high numbers when no broad spectrum insecticides are used.     

Diapause dynamics, seasonal phenology, and pupal color dimorphism of Papilio polyxenes in southern Florida, USA

In the European grapevine moth, Lobesia botrana (Denis and Schiffermüller) (Lepidoptera: Tortricidae), it has recently been shown that volatiles emitted from the main host plant, grapevine, are attractive to adult females. Here, using wind tunnel experiments, we tested the attractiveness of various grapevine, Vitis vinifera L. (Vitaceae), plant parts at different phenological stages, including ripe berries infested with the pathogenic fungus Botrytis cinerea (Persoon: Fries) (Sclerotiniaceae) to laboratory‐reared virgin and mated male and female moths. We also tested the attractiveness of the non‐host plant, tansy [Tanacetum vulgare (L.) (Asteraceae)], as flowers and flower volatiles were previously shown to be attractive to L. botrana females in the field. Mated female moths were the only adults to exhibit upwind orientation to grape plant parts in the flight tunnel. The most attractive parts of the grapevine plants were leaves, flower buds, and ripe berries. No attraction was observed to flowers. This corresponds to the phenological stages available when females of the 2–3 generations during a year are present in the field. No attraction was observed to leaves and flowers of tansy.     

Characterisation of a new species of Pythium isolated from a wheat field in northern France and its antagonism towards Botrytis cinerea causing the grey mould disease of the grapevine

A new species, Pythium bifurcatum, isolated from soil samples taken from a wheat field in Lille in northern France is described here. The oomycete occurred thrice out of 50 samples. The type specimen is F-91, which is a slow-growing saprophyte living on vegetable debris and which can be recognised by its antheridial as well as oogonial characteristics, which are different from other known species of Pythium. When grown together with Botrytis cinerea, the causal agent of the grey mould disease of the grapevine, Pythium bifurcatum shows a pronounced antagonism and suppresses its growth. Morphological features of this new species, its antagonism to B. cinerea, the sequences of the ITS region of its nuclear ribosomal DNA, and its comparison with related species are discussed in this article.     

Characterisation of Pythium paroecandrum and its antagonism towards Botrytis cinerea, the causative agent of grey mould disease of grape

Pythium paroecandrum (B-30), an oomycete, was isolated from soil samples taken from a wheat field in Genlis in the Burgundy region of France and was found to check the growth and development of Botrytis cinerea, a serious grapevine pathogen. The oomycete is a fast-growing organism, living on vegetable debris, and can be recognised by its catenulate hyphal swellings, catenulate oogonia, and monoclinous antheridia. When grown together with B. cinerea, the causal agent of the grey mould disease of the grapevine, P. paroecandrum shows a pronounced antagonism and suppresses its growth and its aptitude to provoke the grey mould symptoms. Morphological features of this oomycete, its antagonism to B. cinerea, the sequences of the internal transcribed spacer region of its nuclear ribosomal DNA, and its comparison with related species are discussed in this article.     

Proteinase inhibitors in Nauphoeta cinerea midgut.

Proteinase inhibitors were studied in the midgut of Nauphoeta cinerea Oliv. (Blattoptera: Blaberidae) in experimental conditions, excluding their nutritional origin. One trypsin inhibitor (TI) with M(r) 8,000 and two subtilisin inhibitors (SI1 and SI2) with M(r) 13,000 and 8,000 were detected after fractionation of total protein preparation on Sephadex G-50. Ninety-four percent of both types of inhibitors was located in anterior midgut (AM). TI was 120-fold purified by FPLC-chromatography on Mono Q. Its isoelectric point was 4.3. TI lost a large part of activity in acidic and especially in alkaline medium. TI, SI1, and SI2 effectively inhibited activities of endogenous proteinases from posterior midgut (PM) of the cockroach. A search for inhibitor of endogenous unusual SH-dependent proteinase from AM revealed in AM a new inhibitor with M(r) 18,000. It was also inactivated in alkaline medium and was effective against proteinases from PM along with unusual SH-dependent proteinase from AM. A mechanism of regulation of activity of midgut proteinases is proposed based on pH-stability of inhibitors.     

病原侵染对采后葡萄激素水平的影响

外源ABA处理采后葡萄可显著促进乙烯释放和抑制IAA的生成,加重葡萄落粒。乙烯利对ABA促进作用不明显,但显著抑制IAA和GA3的生成。葡萄感病后组织内源激素水平发生了变化：ABA含量显著增加,乙烯释放率增大,IAA含量显著减少,这种变化趋势在果梗中尤为突出。     

芳樟醇对灰葡萄孢生长的影响及对番茄灰霉病的防控效果

通过平板抑菌试验和孢子萌发试验研究了芳樟醇对灰葡萄孢的生长抑制作用,并通过盆栽试验进一步验证了芳樟醇对番茄灰霉病的防控效果。结果表明: 芳樟醇能够显著抑制灰葡萄孢菌丝的生长,半最大效应浓度(EC₅₀)值为0.581 mL·L^-1。孢子萌发试验中,芳樟醇能够有效抑制灰葡萄孢孢子的萌发,并表现出浓度依赖性。芳樟醇处理提高了灰葡萄孢菌菌丝体的相对电导率和丙二醛(MDA)含量,说明芳樟醇可引起氧化损伤效应导致灰葡萄孢菌的膜系统被破坏;芳樟醇处理后灰葡萄孢菌中的超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)活性较对照组分别下降了27.4%、68.9%和26.0%,说明芳樟醇抑制了灰葡萄孢菌体内的抗氧化系统。盆栽试验结果显示,芳樟醇处理的病斑直径较对照组显著降低;番茄叶片中的SOD、CAT、POD、多酚氧化酶和苯丙氨酸解氨酶活性均显著高于对照组;而MDA含量下降了41.5%,说明芳樟醇可减轻灰葡萄孢菌对番茄植株造成的氧化损伤以提高植物抗病性。综上,芳樟醇对灰葡萄孢的生长有显著抑制作用并对番茄灰霉病有较好的防治效果,研究结果可为开发新型植物源抑菌剂防控番茄灰霉病提供理论依据。     

Sexual conflict and cooperation under naturally occurring male enforced monogamy

An evolutionary conflict often exists between the sexes in regard to female mating patterns. Females can benefit from polyandry, whereas males mating with polyandrous females lose reproductive opportunities because of sperm competition. Where this conflict occurs, the evolution of mechanisms whereby males can control female remating, often at a fitness cost to the female, are expected to evolve. The fitness cost to the female will be increased in systems where a few high status males monopolise mating opportunities and thus have limited sperm supplies. Here we show that in the cockroach Nauphoeta cinerea, a species where males enforce female monogamy in the first reproductive cycle, males that have become sperm depleted continue to be able to manipulate female remating behaviour. Although the manipulation severely decreases fecundity in females mated to sperm-depleted males, males benefit, increasing their relative fitness by preventing other males from reproducing. Our results suggest that there is selection on maintaining the mechanism of manipulation rather than maintaining sperm numbers. Taken with previous research on sexual conflict in N. cinerea, this study suggests that the causes and consequences of sexual conflict are complex and can change across the life history of an individual.     

The BOS loci of Arabidopsis are required for resistance to Botrytis cinerea infection

Three Botrytis-susceptible mutants bos2, bos3, and bos4 which define independent and novel genetic loci required for Arabidopsis resistance to Botrytis cinerea were isolated. The bos2 mutant is susceptible to B. cinerea but retains wild-type levels of resistance to other pathogens tested, indicative of a defect in a response pathway more specific to B. cinerea. The bos3 and bos4 mutants also show increased susceptibility to Alternaria brassicicola, another necrotrophic pathogen, suggesting a broader role for these loci in resistance. bos4 shows the broadest range of effects on resistance, being more susceptible to avirulent strain of Pseudomonas syringae pv. tomato. Interestingly, bos3 is more resistant than wild-type plants to virulent strains of the biotrophic pathogen Peronospora parasitica and the bacterial pathogen P. syringae pv. tomato. The Pathogenesis Related gene 1 (PR-1), a molecular marker of the salicylic acid (SA)-dependent resistance pathway, shows a wild-type pattern of expression in bos2, while in bos3 this gene was expressed at elevated levels, both constitutively and in response to pathogen challenge. In bos4 plants, PR-1 expression was reduced compared with wild type in response to B. cinerea and SA. In bos3, the mutant most susceptible to B. cinerea and with the highest expression of PR-1, removal of SA resulted in reduced PR-1 expression but no change to the B. cinerea response. Expression of the plant defensin gene PDF1-2 was generally lower in bos mutants compared with wild-type plants, with a particularly strong reduction in bos3. Production of the phytoalexin camalexin is another well-characterized plant defense response. The bos2 and bos4 mutants accumulate reduced levels of camalexin whereas bos3 accumulates significantly higher levels of camalexin than wild-type plants in response to B. cinerea. The BOS2, BOS3, and BOS4 loci may affect camalexin levels and responsiveness to ethylene and jasmonate. The three new mutants appear to mediate disease responses through mechanisms independent of the previously described BOS1 gene. Based on the differences in the phenotypes of the bos mutants, it appears that they affect different points in defense response pathways.