Summary The effects of salicylic acid (SA), Trichoderma viride and Pseudomonas fluorescens CHA0 w... more Summary The effects of salicylic acid (SA), Trichoderma viride and Pseudomonas fluorescens CHA0 were studied on the root-knot nematode Meloidogyne incognita race 2 in resistant and susceptible tomato cultivars (Gina VF, Falat CH, Falat 111, Karoon) during 2012-2013. Four-leaf tomato seedlings were used, grown in pots containing 1000 g of sterilized soil; each seedling receiving 20 ml of T. viride suspension containing 1×106 spores, 30 ml of P. fluorescens CHA0 with 109 cfu/ml, 5mM of salicylic acid and 2000 second stage nematode juveniles. Parameters relevant to nematode population and plant growth were evaluated. The biocontrol agents and salicylic acid were effective in nematode control in combined and single treatments. High reductions in root galling and egg mass indices were observed with combination of SA and biocontrol agents. The greatest increase in plant growth was obtained when cv. Falat CH was treated with SA followed by P. fluorescens CHA0 and T. viride. The highest num...
Desert truffles, hypogeous Pezizales (Ascomycota), are difficult to identify due to evolutionary ... more Desert truffles, hypogeous Pezizales (Ascomycota), are difficult to identify due to evolutionary convergence of morphological characters among taxa that share a similar habitat and mode of spore dispersal. Also, during their symbiotic phase, these are barely distinguishable morphologically, and molecular probes are needed for their identification. We have developed a PCR-based method for the identification of Picoa juniperi and Picoa lefebvrei based on internal transcribed spacers of rDNA. Two PCR primers specific for P. lefebvrei (FLE/RLE) and two specific for P. juniperi (FJU/RJU) were designed. A collection of samples from different geographical areas representing diversity of these species were examined for unique regions of internal transcribed spacers 1, 2 and 5.8S gene of rDNA (ITS) compared to other closely related species. Annealing temperatures and extension times were optimized for each set of primers for maximum specificity and efficiency. They proved to be efficient to specifically detect the presence of P. juniperi and P. lefebvrei by PCR and neither set amplified purified DNA from other truffle species as well as some ascomycetous fungi. The partial small subunit of ribosomal DNA genes of P. juniperi were amplified with the genomic DNA extracted from Helianthemum ledifolium var. ledifolium roots by nested polymerase chain reaction (PCR) using the universal fungal primer pair ITS1/ITS4 and specific primer pair FTC/RTC, which was designed based on internal transcribed spacer 1, 2 and 5.8S gene of rDNA sequences of P juniperi. The nested-PCR was sensitive enough to re-amplify the direct-PCR product, resulting in a DNA fragment of 426 bp. The efficacy of nested-PCR showed that it could re-amplify the direct-PCR product and detect 200 fg genomic DNA.
During 2012, five isolates of pycnidial fungi were recovered from roots of tomato (Solanum lycope... more During 2012, five isolates of pycnidial fungi were recovered from roots of tomato (Solanum lycopersicum) plants in Iran. Based on morphological characteristics the presence of Ampelomyces was documented. To confirm morphological identification and clarify the placement of endophytic isolates of Ampelomyces, DNA was extracted from isolates using a genomic DNA purification Kit. Region of internal transcribed spacers 1, 2 and 5.8S genes of rDNA were amplified using ITS4 and ITS1 universal primer set. Amplicons were purified, sequenced and submitted to the GenBank. The resulting sequence (600 bp) was submitted to a BLAST search to find most similar sequences in GenBank. The ITS sequences of isolates obtained in Iran were compared to those of other related authentic sequences obtained from GenBank. Iranian endophytic isolates had 100 % similarity of among themselves, while all isolates of Ampelomyces sequences analyzed had an average of 95.2 % (range 87-100 %) similarity. When Ampelomyce...
Pythium and Phytophthora are among the most well-known plant pathogens around the world that caus... more Pythium and Phytophthora are among the most well-known plant pathogens around the world that cause rotting of seeds, root, and crown, seedling death, and soft rot of fruits in contact with the soil. In this research, 347 isolates of these two genera and their close genus, Phytopythium were isolated from the cucurbits fields in Kermanshah province, Iran and examined in terms of morphological and physiological characteristics. ITS-rDNA region and the partial cytochrome oxidase II (cox II) gene from the selected isolates were amplified and sequenced to confirm the morphological identification. Based on the morphological , morphometrical, physiological, and phylogen-etic examinations, nine species of Pythium including P. aphanidermatum, P. dissotocum, P. catenulatum, P. kashmirense, P. middletonii, P. nodosum, P. oligandrum, P. torulosum, and P. ultimum; two species of Phytopythium including Pp. mercuriale and Pp. litorale, and three species of Phytophthora including Ph. melonis, Ph. nicotianae, and Ph. parasitica were detected. Among the species identified in this study, Pp. mercuriale was a new record for mycobiota of Iran and two species, P. aphanidermatum and P. ultimum were isolated more frequently.
Yeasts are a polyphyletic group of ascomycete and basidiomycete fungi characterized by having a u... more Yeasts are a polyphyletic group of ascomycete and basidiomycete fungi characterized by having a unicellular growth phase and sexual stages that are not enclosed in fruiting bodies. An attempt was made to identify yeast species in uncultivated soils collected from different areas of Kermanshah province, Iran, by analyzing hypervariable D1/D2 domain of the large subunit (LSU) rDNA gene sequence and comparing the sequences with that available in NCBI database. In this study, 25 soil samples were analyzed and eight species including
Summary The effects of salicylic acid (SA), Trichoderma viride and Pseudomonas fluorescens CHA0 w... more Summary The effects of salicylic acid (SA), Trichoderma viride and Pseudomonas fluorescens CHA0 were studied on the root-knot nematode Meloidogyne incognita race 2 in resistant and susceptible tomato cultivars (Gina VF, Falat CH, Falat 111, Karoon) during 2012-2013. Four-leaf tomato seedlings were used, grown in pots containing 1000 g of sterilized soil; each seedling receiving 20 ml of T. viride suspension containing 1×106 spores, 30 ml of P. fluorescens CHA0 with 109 cfu/ml, 5mM of salicylic acid and 2000 second stage nematode juveniles. Parameters relevant to nematode population and plant growth were evaluated. The biocontrol agents and salicylic acid were effective in nematode control in combined and single treatments. High reductions in root galling and egg mass indices were observed with combination of SA and biocontrol agents. The greatest increase in plant growth was obtained when cv. Falat CH was treated with SA followed by P. fluorescens CHA0 and T. viride. The highest num...
Desert truffles, hypogeous Pezizales (Ascomycota), are difficult to identify due to evolutionary ... more Desert truffles, hypogeous Pezizales (Ascomycota), are difficult to identify due to evolutionary convergence of morphological characters among taxa that share a similar habitat and mode of spore dispersal. Also, during their symbiotic phase, these are barely distinguishable morphologically, and molecular probes are needed for their identification. We have developed a PCR-based method for the identification of Picoa juniperi and Picoa lefebvrei based on internal transcribed spacers of rDNA. Two PCR primers specific for P. lefebvrei (FLE/RLE) and two specific for P. juniperi (FJU/RJU) were designed. A collection of samples from different geographical areas representing diversity of these species were examined for unique regions of internal transcribed spacers 1, 2 and 5.8S gene of rDNA (ITS) compared to other closely related species. Annealing temperatures and extension times were optimized for each set of primers for maximum specificity and efficiency. They proved to be efficient to specifically detect the presence of P. juniperi and P. lefebvrei by PCR and neither set amplified purified DNA from other truffle species as well as some ascomycetous fungi. The partial small subunit of ribosomal DNA genes of P. juniperi were amplified with the genomic DNA extracted from Helianthemum ledifolium var. ledifolium roots by nested polymerase chain reaction (PCR) using the universal fungal primer pair ITS1/ITS4 and specific primer pair FTC/RTC, which was designed based on internal transcribed spacer 1, 2 and 5.8S gene of rDNA sequences of P juniperi. The nested-PCR was sensitive enough to re-amplify the direct-PCR product, resulting in a DNA fragment of 426 bp. The efficacy of nested-PCR showed that it could re-amplify the direct-PCR product and detect 200 fg genomic DNA.
During 2012, five isolates of pycnidial fungi were recovered from roots of tomato (Solanum lycope... more During 2012, five isolates of pycnidial fungi were recovered from roots of tomato (Solanum lycopersicum) plants in Iran. Based on morphological characteristics the presence of Ampelomyces was documented. To confirm morphological identification and clarify the placement of endophytic isolates of Ampelomyces, DNA was extracted from isolates using a genomic DNA purification Kit. Region of internal transcribed spacers 1, 2 and 5.8S genes of rDNA were amplified using ITS4 and ITS1 universal primer set. Amplicons were purified, sequenced and submitted to the GenBank. The resulting sequence (600 bp) was submitted to a BLAST search to find most similar sequences in GenBank. The ITS sequences of isolates obtained in Iran were compared to those of other related authentic sequences obtained from GenBank. Iranian endophytic isolates had 100 % similarity of among themselves, while all isolates of Ampelomyces sequences analyzed had an average of 95.2 % (range 87-100 %) similarity. When Ampelomyce...
Pythium and Phytophthora are among the most well-known plant pathogens around the world that caus... more Pythium and Phytophthora are among the most well-known plant pathogens around the world that cause rotting of seeds, root, and crown, seedling death, and soft rot of fruits in contact with the soil. In this research, 347 isolates of these two genera and their close genus, Phytopythium were isolated from the cucurbits fields in Kermanshah province, Iran and examined in terms of morphological and physiological characteristics. ITS-rDNA region and the partial cytochrome oxidase II (cox II) gene from the selected isolates were amplified and sequenced to confirm the morphological identification. Based on the morphological , morphometrical, physiological, and phylogen-etic examinations, nine species of Pythium including P. aphanidermatum, P. dissotocum, P. catenulatum, P. kashmirense, P. middletonii, P. nodosum, P. oligandrum, P. torulosum, and P. ultimum; two species of Phytopythium including Pp. mercuriale and Pp. litorale, and three species of Phytophthora including Ph. melonis, Ph. nicotianae, and Ph. parasitica were detected. Among the species identified in this study, Pp. mercuriale was a new record for mycobiota of Iran and two species, P. aphanidermatum and P. ultimum were isolated more frequently.
Yeasts are a polyphyletic group of ascomycete and basidiomycete fungi characterized by having a u... more Yeasts are a polyphyletic group of ascomycete and basidiomycete fungi characterized by having a unicellular growth phase and sexual stages that are not enclosed in fruiting bodies. An attempt was made to identify yeast species in uncultivated soils collected from different areas of Kermanshah province, Iran, by analyzing hypervariable D1/D2 domain of the large subunit (LSU) rDNA gene sequence and comparing the sequences with that available in NCBI database. In this study, 25 soil samples were analyzed and eight species including
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