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Guglielmo Lione Luana Giordano Fabiano Sillo Francesca Brescia Paolo Gonthier 《Plant pathology》2021,70(9):2016-2033
Two chestnut (Castanea sativa) orchards of north-western Italy were sampled with passive spore traps 35 times over 24 months. Samples were analysed through a newly developed quantitative PCR assay to quantify propagule loads of the emerging fungal pathogen Gnomoniopsis castaneae. Average propagule deposition patterns were assessed along with temporal and climatic variables, including sampling month and season, temperatures, relative humidity, precipitations, and wind. Machine learning algorithms combining information theory, fractal analysis, unbiased recursive partitioning, ordinary least squares and logistic regressions, were used to model propagule deposition patterns. The trained models were validated on independent data gathered from 24 samplings conducted in a third chestnut orchard during the same timeframe. Results showed that propagule deposition rate (DR) was variable within and among sites, with a site average ranging from 173 to 765 spores ⋅m−2 ⋅h−1. Propagule deposition was observed across all seasons, although the DR dropped substantially during wintertime (p < 0.05). Mean, maximum, and minimum temperatures, the growing degree days at 0 and 5℃ thresholds, and wind gust were all positively correlated (p < 0.05) with DR of G. castaneae. The trained models were all significant (p < 0.05), as well as their validation (p < 0.05). Fluctuations of propagule deposition throughout the year were consistent among sites and proved to be driven by temperatures. Wind gust was associated with the overall amount of propagules deposited at site level. In future, the increase in temperatures and strong winds as a result of climate change may boost the spread of G. castaneae. 相似文献
3.
Song Yang Shao-wei Zhai Brian S. Shepherd Fred P. Binkowski Silas S.O. Hung Wendy M. Sealey Dong‐Fang Deng 《Aquaculture Nutrition》2019,25(6):1171-1182
Two 3‐week growth trials were performed to determine the optimum feeding rate of juvenile lake sturgeon (Acipenser fulvescens) fed with a semi‐purified dry diet (protein, 440 g; lipid, 130 g/kg) at different feeding rates: 5, 10, 20, 30, and 40 g/kg body weight per day (BW/.d‐1), for 36 g‐sized fish; and 2.5, 5, 10, 20, and 30 g/kg BW/.d‐1, for 80 g sized fish. Feeding rates significantly influenced growth performances, feed conversion ratio, wholebody lipid and moisture contents, energy and protein retention, and fasted blood glucose levels (p < 0.05). The ratio of total C/total N measured in whole fish was positively correlated to the feeding rates and the lipid contents of whole fish. Suboptimal feeding significantly depressed growth performance and protein synthesis based on the measurement of RNA/DNA ratio in white muscle. Based on polynomial regression models, an optimal feeding rate to support the maximum growth, protein and energy retention was 34.5, 22 and 27.3 g/kg BW/.d‐1, respectively, for fish sized at 36–72 g; and 29.0, 16.9 and 19.9 g/kg BW/.d‐1, respectively for fish sized at 80–140 g. Results of this study will benefit future research to develop practical feeds to replace frozen live feed and feed management for lake sturgeon. 相似文献
4.
A molecular diagnostic assay for the detection and identification of wood decay fungi of conifers 
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下载免费PDF全文 Ten taxon‐specific primers were designed to amplify the Internal Transcribed Spacer of the rRNA operon of several important decay fungi of coniferous wood, including Armillaria spp., Echinodontium spp., Fomitopsis pinicola, Fuscoporia torulosa, Heterobasidion annosum sensu lato (s.l.), Onnia spp., Phaeolus schweinitzii, Phellinus weirii s.l., Pholiota spp. and Porodaedalea spp. Primers designed in this study and in a previous one for the identification of Laetiporus sulphureus and Stereum spp. were combined in two multiplex PCRs, which were tested for efficiency and specificity, and detected at least 1 pg of fungal target DNA. Target DNA at concentrations of 10?1 pg or lower can be detected with this assay using SYBR® Green Real‐Time PCR. Validation assays performed on 129 naturally infected wood samples or fruiting bodies confirmed the reliability of the multiplex PCR‐based diagnostic method. This method represents a simple and rapid diagnostic tool for the detection of a number of destructive wood decay fungi of conifer wood. 相似文献
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Kofi Fynn-Aikins Silas S. O. Hung Steven G. Hughes 《Fish physiology and biochemistry》1993,12(4):317-325
Juvenile white sturgeon (Acipenser transmontanus) were fed three isonitrogenous and isoenergetic diets containing either 35% D-glucose (HC), a mixture of 20% dextrin and
10% cellulose (MC), or 23% cellulose (LC), to investigate the effects of dietary carbohydrate on liver function. After 8-week
feeding, body weight gain of fish fed the HC diet was consistently higher than that of fish fed the MC and LC diets, but was
not significantly different from the MC-fed fish. Fish fed the HC diet had significantly (p < 0.05) higher feed efficiencies
and liver glycogen concentrations than fish fed the MC and LC diets. Sturgeon were injected intravenously with 10 mg kg-1 body weight of sulfobromophthalein (BSP) and post-injection blood taken from the caudal vein at 15, 30, 60, and 120 min.
No significant differences in plasma BSP concentrations were found among the treatments at these times. Plasma hemoglobin
and activities of aspartate and alanine aminotransferase were not affected by the diets. This study suggests that the HC diet
does not adversely affect liver function or weight gain. Inclusion of high dietary levels of digestible and inexpensive carbohydrates
in commercial sturgeon feeds seems promising, but long-term feeding trials should be conducted to confirm this assertion. 相似文献
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Testing and modelling the effects of climate on the incidence of the emergent nut rot agent of chestnut Gnomoniopsis castanea 下载免费PDF全文
下载免费PDF全文 Gnomoniopsis castanea is an emerging fungal pathogen causing nut rot of sweet chestnut, Castanea sativa. This study was aimed at testing and modelling the effects of climate on disease incidence. Up to 120 ripe nuts were collected in 2011 from trees in each of 12 sites located in the northwest of Italy. The incidence of G. castanea in each site was expressed as the number of infected nuts out of the total number of nuts sampled (%), determined by combining the results of morphological identification of isolates obtained from nuts, and their typing through a newly developed taxon‐specific molecular assay. Disease incidence ranged from 20 to 93%, depending on site. Geostatistical analyses revealed that, despite the clustering of sites (P < 0·05), disease incidence was not spatially autocorrelated (P > 0·05). This finding suggests that the disease is influenced by site‐dependent factors whose scale (c. 7·5–15·6 km) is consistent with the climate variability throughout the sampling region. Multivariate analyses on maximum, mean and minimum temperatures and on rainfall showed that warmer temperatures were associated with higher levels of disease incidence. The temperatures of months before nut harvesting were selected as predictors for partial least squares regression (PLSR) models (GnoMods) of G. castanea incidence. External validation on data collected either on sites or in years not used for model fitting showed the good predictive abilities of the GnoMods (Spearman's ρobs/pred > 0·72, P < 0·05). The above findings support a relationship between climate and incidence of G. castanea, providing statistical tools to forecast disease incidence at site level. 相似文献
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Gas chromatography mass spectroscopy was applied to characterize the metabolic profiles of hatchery-reared mussel (Perna canaliculus) larvae before and after a prolonged handling and water exchange process, and to investigate the effect of culture conditions. A decrease in succinate and an increase in alanine were observed after the water exchange, which indicated alterations in energy production and osmotic balance. However, these variations were subtle and it is unlikely that the water exchange practice had any lasting negative effects on larval physiology and performance. Multivariate pattern recognition tools (hierarchical clustering, principal component analysis and projection to latent squares discriminant analysis) were used to assess metabolite variations in larvae reared in low-density static and high-density flow through systems and to construct a culture condition classification model. Twelve metabolites contributed most towards the model, which indicated differences in energy, protein and lipid metabolism. The clear group separations were not represented by observable variations in morphological traits. This suggests that growth performance is metabolically buffered through an adaptive physiological mechanism to provide similar developmental characteristics under these conditions. 相似文献
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Fast and specific detection of the invasive forest pathogen Heterobasidion irregulare through a Loop‐mediated isothermal AMPlification (LAMP) assay 下载免费PDF全文
下载免费PDF全文 Heterobasidion irregulare is one of the most destructive fungal pathogens of pines in North America and was accidentally introduced into central Italy, where it has become invasive. The fungus is currently recommended for regulation by the European and Mediterranean Plant Protection Organisation (EPPO). In this work, an efficient diagnostic tool for the early detection of H. irregulare based on Loop‐mediated isothermal AMPlification (LAMP) coupled with two different DNA extraction methods was developed. The LAMP assay showed high specificity and good sensitivity, with a limit of detection of about 20 picograms of target DNA and time of detection of less than 40 min. The assay was successfully tested on a variety of different samples, including fungal fruiting bodies, infected plants and colonized wood. A survey on environmental samples collected in the field was also performed using the LAMP assay coupled with a rapid DNA extraction method. The possible applications of this molecular diagnostic tool encompass the monitoring of pine forests surrounding the current invasion area, laboratory or in‐field analyses of samples from suspected trees, and the surveillance in the ports of entry of wood imported from North America. 相似文献
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Maria Carlota Vaz Patto Pedro Manuel Moreira Nuno Almeida Zlatko Satovic Silas Pego 《Euphytica》2008,161(1-2):283-291
Natural, and in particular, artificial (human) selection may pose a danger to the existing crop genetic diversity. Nevertheless,
on-farm breeding systems seem to achieve phenotypic improvements even though preserving variability. Using SSR markers, we
analysed several selection cycles, over a 20 years period, of a Portuguese on-farm participatory maize OPV-‘Pigarro’ breeding
project. No significant differences in allelic richness (Nar), observed heterozygosity (HO), expected heterozygosity (or gene diversity; HE) or inbreeding coefficient (f) were detected among the selection cycles. 58 out of 107 alleles were common to all the selection
cycles studied. The analysis of molecular variance showed that the variation among selection cycles represented only 7% of
the total molecular variation. However, the number of private alleles varied among the selection cycles, being the highest
detected at the beginning of the selection project. These findings demonstrate that an allele flow took place during the on-farm
selection process of ‘Pigarro’ but the level of genetic diversity was not significantly influenced. Since interesting phenotypic
improvements were also achieved, on-farm breeding projects, like this one, should be valued as a way to preserve unique Portuguese
maize landraces in risk of disappearing. 相似文献
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Ibrahim Silas Akos Mohd Y. Rafii Mohd Razi Ismail Shairul Izan Ramlee Noraziyah Abd Aziz Shamsudin Asfaliza Ramli Samuel Chibuike Chukwu Senesie Swaray Momodu Jalloh 《水稻科学》2021,28(3):279-288
Improved rice lines were developed frome three parents with the resistance or tolerance to bacterial leaf blight, blast and drought stress, respectively, using single-, double- and three-way crosses. The improved lines were assessed for agro-morphological and yield traits under non-drought stress (NS) and reproductive-stage drought stress (RS) treatments. The mean comparison of traits measured between parent plants and progenies (improved lines) were similar, and there were significant and non-significant differences among the parents and improved lines (genotypes) under NS and RS. Smilarly, there was significant and non-significant differences in the interaction among both parent varieties and improved lines for NS and RS. Cluster and 3D-model of principal component analysis did not generate categorical clusters according to crossing methods, and there were no exclusive crossing method inclined variations under the treatments. The improved lines were high-yielding, disease resistant, and drought-tolerant compared with their parents. All the crossing methods were good for this crop improvement program without preference to any, despite the number of genes introgressed. 相似文献