Russian olive trees (Elaeagnus angustifolia) showing witches' broom symptoms typical of phytoplasma infection were observed in the Urmia region of Iran. A phytoplasma named Russian olive witches' ...broom phytoplasma (ROWBp-U) was detected from all symptomatic samples by amplification of the 16S rRNA gene and 16S/23S rDNA spacer region using the polymerase chain reaction (PCR) which gave a product of expected length. DNA from symptomless plants used as a negative control yielded no product. The sequence of the 16S rRNA gene and 16S/23S rDNA spacer region of ROWBp-U showed 99% similarity with the homologous genes of members of the aster yellows group. We also detected a phytoplasma in neighboring alfalfa plants (AlWBp-U) showing severe witches' broom symptoms. An 1107 bp PCR product from the 16S rRNA gene showed 99% homology with the corresponding product in ROWBp-U, suggesting the presence of the same phytoplasma actively vectored in the area. Further observations showed that Russian olive trees with typical ROWB symptoms were present in an orchard near Tehran which is located over 530 km south-east of the original Urmia site. The corresponding sequence of this phytoplasma (ROWBp-T) showed 99% homology to that of the ROWBp-U. A sequence homology study based on the 16S rRNA gene and 16S/23S rDNA spacer region of ROWBp-U and other phytoplasmas showed that ROWBp-U is most closely related to the 16SrI group. To our knowledge, this is the first report of a phytoplasma infection in a member of the Elaeagnaceae.
Basal stem rot, caused by Sclerotinia sclerotiorum (Lib.) de Bary, is an important cause of yield loss in sunflower (Helianthus annuus L.). Quantitative trait loci (QTLs) implicated in partial ...resistance to basal stem rot disease were identified using 116 recombinant inbred lines (RILs) from the cross between the sunflower parental lines PAC2 and RHA266. The RILs and their parents were arranged in a completely randomized design with six replications and inoculated with a moderately aggressive isolate (SSU107) of S. sclerotiorum under controlled conditions. QTLs were mapped using a recently developed high-density simple sequence repeat/ amplified fragment length polymorphism (SSR/AFLP) sunflower linkage map. Analysis of variance showed highly significant differences among the sunflower genotypes for susceptibility to basal stem rot. The frequency distribution of genotypes for susceptibility to disease showed continuous patterns, suggesting that resistance is controlled by a polygenic system. Transgressive segregation for resistance occurred in this cross. Composite interval mapping analysis revealed 7 QTLs for percentage necrotic area, localized on 7 linkage groups. The effects of QTLs were small to moderate indicating a polygenic control of the studied character. However, like any other quantitative trait, it is necessary to confirm the position of the QTLs and to carry out fine-scale mapping before marker assisted selection (MAS) can be done. LG8 and LG16 are good candidates for further analysis to develop molecular markers for resistance to Sclerotinia disease.
Storage insect pests are a major threat for packaged foodstuffs and most packages have low permeability to the fumigant gases used for control. In this study, the effects of O3 gas concentrations ...(50, 100, 150 ppm) in the atmosphere of 70% CO2 on adults of Confused flour beetle placed inside three foodstuffs including; wheat (alive), wheat flour and rolled oats (inanimate) packed with laser perforated BOPP film with 80 μ width, were evaluated. The experiments performed at 25 ± 2 °C and 35 ± 5% r.h. with exposure period seven days. The results showed that the regression models between permeability index (PI) of Bopp film and insect mortality in three different foodstuffs and also empty packages were different. Regression model for packaged wheat was quadratic, for wheat flour and rolled oats was power and in empty packages, linear model was fitted with 95% confidence. The additive effect between O3 and CO2 gases on pest mortality placed in empty non-perforated film was found. Other results proved that the mean mortality in three products in the same condition is different and highest mortality was observed in wheat. Also, the interactions observed between factors at 0.05 level. Present study suggests laser perforated BOPP films as a proper packaging for inanimate products and non-perforated BOPP films for live products.
•We offer a new model according to MAs called Gas-permeable Packaging (GPP).•The treatment of O3 + CO2 mixture has additive effect on mortality in packages without foodstuffs with 95% confidence.•The relationship between mortality rate and permeability index of films in foodstuffs treatment were fitted Non-linear models.•We observe two interactions between Foodstuffs, permeability index and Ozone concentration treatments at 0.05 level.
ABSTRACT
In this study, antifungal activities of Thymus vulgaris L., Eugenia caryophyllata L., Cinnamomum zeylanicum Blume and Carum copticum L. essential oils against Monilinia fructicola and ...Botrytis cinerea, two important postharvest pathogens of stone fruit, were investigated under in vivo studies. Results showed that the essential oil treatments, especially T. vulgaris and E. caryophyllata oils, had a good antifungal activity in reduction of both disease incidence and disease severity of brown and gray mold rots caused by M. fructicola and B. cinerea on apricots, respectively. Gas chromatography (GC) and GC/mass spectrometry analysis of tested essential oils showed that thymol (37.55%), eugenol (48.76%), cinnamaldehyde (90.33%) and thymol (50.88%) were the main components of T. vulgaris, E. caryophyllata, C. zeylanicum, C. copticum oils, respectively. Application of C. copticum and E. caryophyllata oils on apricot fruit showed a significant effect on fruit quality retention as evaluated with weight loss (%), fruit firmness, total soluble solids, titratable acidity and maturity index in sensory parameters. These results revealed that T. vulgaris and E. caryophyllata oils could be natural alternatives to fungicides in the control of M. fructicola and B. cinerea infections.
PRACTICAL APPLICATIONS
Because of problems related to synthetic fungicide application, calls for research into new potential safe strategies for control of postharvest decay in crops. Plant products, especially essential oils, are one of the most promising groups of natural compounds for development of indigenous nature, nonmammalian toxicity and antimicrobial agents and their employment for the control of different postharvest pathogens is also well documented. The results of in vivo (cold storage of fruits) experiments, in this study, showed that essential oil treatment had significant effects on fungal growth. The number of infected fruits and disease severity were reduced in oil‐treated fruit and with increase of essential oil concentration the fungal growth decreased. Therefore, these compounds could be an alternative to chemical fungicides for the control of postharvest fungal diseases on apricot fruits. In addition, the application of plant essential oils could be named as new safe method for control of agricultural products.
ABSTRACT
The antifungal activity of essential oils of sweet basil (Ocimum basilicum L.), fennel (Foeniculum vulgare Mill.), summer savory (Satureja hortensis L.) and thyme (Thymus vulgaris L.) ...against two well‐known postharvest fungi, Penicillium digitatum and Rhizopus stolonifer, by poison food medium (0, 200, 400, 600, 800 and 1,000 µL/L) and vapor phase (0, 5, 10, 15, 20, 25 and 40 µL) methods were assayed. The results showed that in poison food medium thyme oil had greatest antifungal activity against P. digitatum and R. stolonifer at 1,000 and ≥600 µL/L, respectively. In vapor phase, thyme oil at ≥5 µL completely inhibited the mycelial growth of pathogens. Summer savory oil at ≥600 µL/L had a significant inhibitory effect on mycelial growth of R. stolonifer. Fennel oil showed the lowest antifungal activity against the pathogens. All the essential oil treatments completely inhibited the growth of R. stolonifer in vapor phase method. Also R. stolonifer were more sensitive against the essential oils. Gas chromatography‐mass spectrometry analysis showed that main compounds identified in sweet basil, fennel, summer savory and thyme oils were linalool (65.25%), trans‐anethole (64.42%), carvacrol (54.14%) and β‐ocimene (12.62%), respectively. Therefore, thyme and summer savory oils have a promising potential to use antifungal agent against fruit and vegetable fungi.
PRACTICAL APPLICATIONS
The results of this work show that thyme, summer savory and fennel oils have a high potential to be used as an antifungal agents for control of postharvest phytopatogenic fungi especially in vapor phase method. Therefore, essential oils as safe aromatic compounds that do have not negative effects on human health and environment may be used as a novel and practical tool for preservation of postharvest quality of horticultural crops and are suitable alternative for synthetic fungicides.
The effects of postharvest spraying of essential oils from sweet basil (Ocimum basilicum), fennel (Foeniculum vulgare), summer savory (Satureja hortensis) and thyme (Thymus vulgaris) on fungal decay ...and quality parameters of the 'Thompson seedless' table grape stored at 0 ± 1°C for 60 days were evaluated. Results showed that the essential oils, especially of thyme and fennel, have a good inhibitory effect on the development of fungal decay in Thompson table grapes. In addition, essential oils reduced weight loss, berry and rachis browning and had no considerable adverse effect on the flavour of the fruits. GC-MS analysis showed that the main compounds identified in sweet basil, fennel, summer savory and thyme oils are linalool (65.25%), trans-anethole (64.72%), carvacrol (54.14%) and β-ocimene (12.62%), respectively. Therefore, these essential oils have good potential for use as an alternative to synthetic fungicides for the preservation and storage of table grapes.
ABSTRACT
The antifungal activity of the essential oils of ajowan, fennel and caraway was evaluated in vitro and in vivo conditions against growth of Alternaria alternata (Fr.: Fr.) Keissler. and ...Penicillium digitatum Sacc., two postharvest pathogens of tomato fruits. In vitro tests showed that ajowan and fennel oils exhibited the highest antifungal activity against A. alternata and P. digitatum, respectively. But caraway exhibited poor antifungal activity against two fungal species tested. Ajowan oil possessed the highest antifungal activity among tested oils in in vivo condition. Gas chromatography–mass spectrometry analysis of essential oils revealed that thymol (63%), trans‐anethole (64%) and 2‐caren‐10‐al (34%) were the main components of essential oils of ajowan, fennel and caraway, respectively. Therefore, essential oils may be used as an alternative for the synthetic chemicals for control of postharvest phytopathogenic fungi and for increasing the shelf life of plant products.
PRACTICAL APPLICATIONS
Because the plant essential oils have low mammalian toxicity, are biodegradable, multifunctional, nonpersistent in the environment and are cheap to produce, the possibility of developing essential oils for use in crop protection may be an attractive venture. This study demonstrates the potential of essential oils as antifungal preservatives for tomato fruits that are susceptible to postharvest decay caused by fungi. Examination of various concentrations of essential oils from ajowan (Carum copticum L.), fennel (Foeniculum vulgare Mill.) and caraway (Carum carvi L.) on Penicillium digitatum and Alternaria alternata in this study showed promising prospects for the utilization of essential oils. In vivo experiments showed that essential oils used could reduce postharvest diseases on tomato fruits caused by P. digitatum and A. alternata. So, essential oils can be used as a potential source of sustainable eco‐friendly botanical fungicides, after successful completion of wide‐range trials.
ABSTRACT
The antifungal activity of different concentrations of Thymus kotschyanus and Carum copticum essential oils (0, 100, 200, 300, 400 and 500 µL/L) on mycelial growth of Botrytis cinerea and ...Penicillium digitatum under in vitro condition were investigated. Also, the preservative property of various concentrations of these essential oils (0, 250 and 500 µL/L) to maintenance quality parameters of “Rish Baba” table grape were studied. Chemical compositions of the essential oils were also determined by gas chromatography–mass spectrometry analysis. Major compounds found in essential oils from T. kotschyanus and C. copticum were carvacrol (28.54%) and thymol (63.18%), respectively. The results of in vitro assay showed that T. kotschyanus and C. copticum essential oils in 300–500 µL/L concentration completely inhibited the mycelial growth of B. cinerea and P. digitatum. Also, at the end of the storage period, all the applied concentration of essential oils reduced disease severity compared to control fruit. The application of essential oil did not affect the berry shrinkage and rachis browning. However, essential oil treatment showed high preservative effect on weight loss, appearance, flavor, berry browning, total soluble solids (TSS), titrable acidity (TA) and TSS/TA of treated fruits. Therefore, essential oils may be used as an alternative for the synthetic chemicals for control of postharvest phytopathogenic fungi, and in turn to fulfill consumer requirements for more natural and healthy fruits.
PRACTICAL APPLICATIONS
Postharvest disease of perishable fruits such as table grape renders heavy losses during transit and storage. Use of chemical fungicides such as SO2 generator pads are basic means of controlling postharvest diseases of table grape. Public awareness about chemical residues in food and interest to use of organic crops intended search to find a new safe alternatives to synthetic fungicides. The main reason for examine the possibility use of essential oils are they plant origins, safe, no side‐effect and their acceptability for consumers. Consequently, recently the interest to use of essential oils to preserve of fruits and vegetables has increased. The goal of this research was to examine the possibility use of T. kotschyanus, C. copticum essential oils to maintain postharvest quality of table grapes.
The interaction of arbuscular mycorrhizal fungi (Glomus etunicatum, Glomus intraradices, and Glomus versiforme) with a wilt-causing soil-borne pathogen, Verticillium dahliae, was studied in cotton. ...It was found that establishment by arbuscular mycorrhizal fungi reduced disease index. In diseased cotton plants colonised by G. etunicatum, the disease index was less than other diseased mycorrhizal and non-mycorrhizal ones. In diseased cotton plants, chlorophyll content was lower than others. Three Glomus species significantly increased content of sugar and protein in shoot and root. Pathogen-infected plants had higher proline concentration in shoot and root than healthy plants. On the other hand, the increased content of proline as stress sensor showed that Verticillium accelerates senescence and reduces yield. These results suggest that the beneficial effects of mycorrhiza can alleviate the pathogenesis effects of V. dahliae partly, and also there is a competitive interaction between the pathogenic and symbiotic fungi.
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