Monitoring oak processionary moth Thaumetopoea processionea L. using pheromone traps: the influence of pheromone lure source,trap design and height above the ground on capture rates

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不同棉花种质资源耐热性的田间鉴定

随着全球气候变暖,高温胁迫已经成为影响棉花产量的主要因素之一。中国棉花种植区,在7月和8月棉花花铃高峰期经常出现周期性极端高温胁迫,导致蕾铃脱落,降低了产量,因此棉花耐热性种质的筛选迫在眉睫。本试验在新疆吐鲁番自然高温条件下,调查200份不同棉花种质资源的脱落率、花粉活力、叶片萎蔫程度、花粉形态、不孕子率等田间性状。然后选择29份不同耐热性种质在河南安阳种植,调查30、35、40、45和50℃离体培养条件下的花粉萌发率。不同耐热性种质资源在自然高温条件下的鉴定指标和室内离体培养花粉萌发率存在着极显著的差异。而且不同鉴定指标间也存在着不同的相关性。结合田间调查结果和花粉离体培养萌发率,将29份种质划分为耐高温型、较耐高温型、高温较敏感型和高温敏感型种质,并初步确定了耐热性的鉴定指标。     

Development of a novel anti-biofilm peptide derived from profilin of Spodoptera frugiperda

Abstract

Candida yeast infections are the fourth leading cause of death worldwide. Peptides with antimicrobial activity are a promising alternative treatment for such infections. Here, the antifungal activity of a new antimicrobial peptide—PEP-IA18—was evaluated against Candida species. PEP-IA18 was designed from the primary sequence of profilin, a protein from Spodoptera frugiperda, and displayed potent activity against Candida albicans and Candida tropicalis, showing a minimum inhibitory concentration (MIC) of 2.5?µM. Furthermore, the mechanism of action of PEP-IA18 involved interaction with the cell membrane (ergosterol complexation). Treatment at MIC and/or 10?×?MIC significantly reduced biofilm formation and viability. PEP-IA18 showed low toxicity toward human fibroblasts and only revealed hemolytic activity at high concentrations. Thus, PEP-IA18 exhibited antifungal and anti-biofilm properties with potential applicability in the treatment of infections caused by Candida species.     

Quantifying the recent expansion of native invasive rush species in a UK upland environment

Rushes, such as soft rush (Juncus effusus L.), hard rush (Juncus inflexus L.), and compact rush (Juncus conglomeratus L.) have become problem species within upland grasslands across the United Kingdom and the coastal grasslands of western Norway. Indeed, being largely unpalatable to livestock and having a vigorous reproductive ecology means that they can rapidly come to dominate swards. However, rush dominance results in a reduction in grassland biodiversity and farm productivity. Anecdotal evidence from the United Kingdom suggests that rush cover within marginal upland grasslands has increased considerably in recent decades. Yet, there is currently no published evidence to support this observation. Here, we use recent and historical Google Earth imagery to measure changes in rush frequency over a 13-year period within four survey years: 2005, 2009, 2015, and 2018. During each survey year, we quantified rush presence or absence using a series of quadrats located within 300 upland grassland plots in the West Pennine Moors, United Kingdom. Data were analysed in two stages, first, by calculating mean rush frequencies per sample year using all the available plot-year combinations (the full dataset), and second by examining differences in rush frequency using only the plots for which rush frequency data were available in every sample year (the continuous dataset). The full dataset indicated that rush frequency has increased by 82% between 2005 and 2018. Similarly, the continuous dataset suggested that rush frequency has increased by 174% over the same period, with the increases in frequency being statistically significant (p < .05) between 2005–2018 and 2009–2018. We discuss the potential drivers of rush expansion in the West Pennine Moors, the ecological and agronomic implications of grassland rush infestations, and priorities for future research.     

Antifungal effect of Penicillium metabolites against some fungi

Microorganisms are increasingly exploited as a source of new biological control agents. Genus Penicillium is a source of novel bioactive molecules which can be used as antifungal agents. The objective of this study was to evaluate the antifungal potential of Penicillium strains. Culture filtrates of two Penicillium species were tested for their antifungal potential by well diffusion assays. Filtrate of Penicillium isolates showed high antifungal effects on mycelial growth of Fusarium oxysporum, Fusarium solani, Macrophomina phaseolina, Aspergillus japonicus var aculeatus and Cladosporium cladosporioides. But Penicillium italicum inhibit the fungal growth from 45 to 68% as compared to Penicillium simplissimum (25–68%). However in case of A. japonicus var aculeatus, Penicillium spp. extracts were equally effective and reduce the colony growth up to 68%. However, P. simplissimum extract was least effective in case of M. phaseolina, where it decreased the colony growth only 25%.     

Aggressiveness spectrum and genetic variability of Fusarium spp. on rice and wheat varieties

Abstract

A total of 106 Fusarium spp. were isolated from infected roots and soil samples of wheat and rice. Of the 106 isolates, 32 from wheat, and 74 from rice, were isolated. Six Fusarium spp. (F. oxysporum, F. moniliforme, F. poae, F. graminearum, F. tricinctum and F. equiseti) were identified at specie level. In aggressiveness tests Fusarium spp. root rot causing fungi were screened out into different aggressiveness classes according to disease severity scales. The aggressiveness of Fusarium spp. was studied on wheat varieties (Inqalab-91 and chakwal-86) and on rice varieties (Basmati-385 and IRRI-6) under controlled conditions. The overall total number of aggressive isolates was higher in rice than in wheat. However, the percentage of severely aggressive isolates was high in wheat, whereas the percentage of moderately and slightly aggressiveness isolates was high in rice. In rice, five isolates were non-aggressive and on wheat 17 were non-aggressive. Random Amplified Polymorphism DNAs (RAPDs) were used to study the polymorphism and genetic variations within the population of Fusarium spp. that established to study correlation between taxonomical and genetical characters of fungi. Five random primers were used P1 (5′-AGGAGGACCC-3′), P2 (5′-ACGAGGGACT-3′), PE7 (5′-AGATGCAGCC-3′), P14 (5′-CCACAGCACG-3′) and PE20 (5′-AACGGTGACC-3′). Each of the 10-mer primers produced results based on the respective banding patterns they generated in present investigations. Primers distinguished the F. oxysporum, F. moniliforme, F. graminearum, F. tricinctum, F. poa and F. equiseti. All the tested primers yielded amplification products, and that were reproducible. Although there was some intraspecific variation with primers, some strains were similar and some were different in banding pattern. In F. oxysporum, F. moniliforme, F. graminearum, F. tricinctum, F. poa and F. equiseti were seen clustered close to one another but each primer separated them unambiguously. All primer (P1, P2, P14, PE7 and PE20) combination produced 62 bands. All primers have shown interspecific and intraspecific variations in banding patterns.     

Vertical distribution of some piercing sucking insects on some roselle varieties in Egypt and the role of amino acids concentration in infestation

Abstract

The cotton aphid, Aphis gossypii Glover was found to be the only aphid species infesting the tested roselle varieties (Sudani, Masri and White), Hibiscus sabdariffa L. which were cultivated in El-Kanater El-khayria (about 30 km north Cairo) as ex situ old land. The vertical distribution of the whitefly, Bemisia tabaci (Genn.); the leafhopper, Empoasca spp. and the pink hibiscus mealy bug, Maconellicoccus hirsutus Green, as insect pests attacking this crop had been studied. Moreover, certain morphological characters and amino acids concentrations in the three varieties of roselle, were obtained. The obtained results indicated that the experimental insect pests severely attacked leaves of the stem nodes from the 8th to the 11th (counting from the top of the plant), whereas whitefly were more abundant on these nodes. All tested insect species were less abundant on the 4th stem node. This may be due to the extensive existence of gland hairs, that excrete some compound especially phenols that might prevent the insects from reproducing on the leaves. The opposite was, however, true for M. hirsutus as it did not attack Sudani and Masri varieties but the infestation occurred at the highest level on the White variety.     

Seasonal variations of Fusarium species in wheat fields in Upper Egypt

Abstract

Populations of the genus Fusarium in wheat fields were studied within the crop-growing season at Qena area (Upper Egypt) using two different types of media (DCPA and DRBA) at 25°C. Fourteen Fusarium species were isolated during this study, namely F. anthophilum, F. aquaeductuum, F. chlamdosporum, F. dimerum, F. merismoides, F. moniliforme, F. oxysporum, F. poae, F. proliferatum, F. sambucinum, F. scripi, F. solani, F. sporotrichioides and F. subglutinans. Fusarium merismoides, F. oxysporum and F. sambucinum were the most common Fusarium species isolated from different wheat plant parts (rhizosphere and rhizoplane) as well as from the wheat fields (soil and air). Fusarium spp. rarely appeared at the beginning of the season and increased sharply between January to March and decreased slightly or sharply at the end of the season according to the type of media and isolation source.     

Evaluation of Trichoderma spp. from central and northern regions of Turkey for suppression of Polymyxa betae as a vector of rhizomania disease

In the current study, 18 Trichoderma spp. isolates were obtained from different provinces in central and northern regions of Turkey. The ability of nine selected isolates to suppress the colonisation of roots by P. betae and the multiplication of BNYVV in sugar beet roots under controlled conditions were tested. Roots of seedlings growing in the P. betae-BNYVV-infested soil were analysed by enzyme-linked immunosorbent assay to test for the presence of BNYVV and checked microscopically for the density of cystosori of P. betae. The numbers of P. betae resting spores in cystosori for each treatment were counted using a light microscope. Except for isolates Tr-1 and Tr-5, the effect of selected Trichoderma isolates on suppressing multiplication of BNYVV varied between 4 and 53%. The total number of resting spores in the roots varied between 14.4 and 25.1 for the different Trichoderma spp. treatments. The lowest number of resting spores in clusters was recorded in T. harzianum Tr-8. In addition, the shapes of resting spores were not normal in the Tr-8 treatments. The cystosori from this treatment were also abnormally dark in colour and had deformed walls.     

Effects of biocontrol agents on lipid and protein composition of Indian mustard seeds from plants infected with Alternaria species

Field experiments were carried out with Indian mustard (Brassica juncea L. Cv RLM 1359) to investigate the influence of biocontrol agents on seeds from plants infected with Alternaria blight. The biocontrol agents viz, Trichoderma harzianum, Pseudomonas fluorescens and Bacillus subtilis were applied as seed treatment/seed treatment coupled with spray on 30 and 60 days after sowing of seeds in experimental fields. The plants treated with different biocontrol agents were more developed than non-treated plants throughout the experiment. Biochemical analysis revealed that application of biocontrol agents resulted in increase in lipid and protein content in seeds from treated plants. The proportion of various lipidic fractions i.e. phospholipids, glycolipids and sterol content in seeds increased with a corresponding decrease in total glycerides. The proportion of 18:3, 20:1 and 22:1 fatty acids increased while that of 18:1 and 18:2 fatty acids decreased in seeds with application of biocontrol agents. There were both qualitative and quantitative differences in the banding patterns of albumin and globulin proteins after application of biocontrol agents. The data suggested that biochemical alterations in the host induced by treatment with biocontrol agents could be associated with defence mechanisms and enhanced growth of the plant.