Weeds as Potential Inoculum Reservoir for Colletotrichum nymphaeae Causing Strawberry Anthracnose in Iran and Rep-PCR Fingerprinting as Useful Marker to Differentiate C. acutatum Complex on Strawberry

Strawberry anthracnose caused by Colletotrichum spp. is considered one of the most serious and destructive disease of strawberry worldwide. Weeds, as possible hosts of the pathogen, could have a role as potential inoculum reservoir. To prove this hypothesis, symptomless weeds were collected in strawberry fields showing anthracnose symptoms in Iran. Ten isolates with Colletotrichum-like colonies were recovered from symptomless Amaranthus viridis L., Convolvulus arvensis L., Fumaria officinalis L., Lactuca serriola L., and Sonchus oleraceus L. plants. The isolates were identified as C. nymphaeae, based on a combination of morphological and sequence data of TUB and GADPH genes. This identification was further validated using Rep-PCR fingerprinting analysis, which produces species-specific DNA fingerprints and unveils inter and intra variation of the species examined in this study. Moreover, rep-PCR marker was used to reveal accurate taxonomic position of Colletorichum spp. causing strawberry anthracnose belonging to the C. acutatum complex, including C. acutatum sensu stricto, C. fiorinae, C. godetiae, C. nymphaeae, C. salicis, and C. simmondsii. The C. nymphaeae isolates originating from symptomless weeds confirmed their pathogenicity on detached strawberry, proving that weeds in strawberry field may have a role as reservoir of inoculum. However, further studies are necessary to quantify their actual contribution to anthracnose epidemics in strawberry fields

Weeds as potential inoculum reservoir for Colletotrichum nymphaeae causing strawberry anthracnose in Iran and Rep-PCR fingerprinting as useful marker to differentiate C. acutatum complex on strawberry

3openInternationalInternational coauthor/editorStrawberry anthracnose caused by Colletotrichum spp. is considered one of the most serious and destructive disease of strawberry worldwide. Weeds, as possible hosts of the pathogen, could have a role as potential inoculum reservoir. To prove this hypothesis, symptomless weeds were collected in strawberry fields showing anthracnose symptoms in Iran. Ten isolates with Colletotrichum-like colonies were recovered from symptomless Amaranthus viridis L., Convolvulus arvensis L., Fumaria officinalis L., Lactuca serriola L., and Sonchus oleraceus L. plants. The isolates were identified as C. nymphaeae, based on a combination of morphological and sequence data of TUB and GADPH genes. This identification was further validated using Rep-PCR fingerprinting analysis, which produces species-specific DNA fingerprints and unveils inter and intra variation of the species examined in this study. Moreover, rep-PCR marker was used to reveal accurate taxonomic position of Colletorichum spp. causing strawberry anthracnose belonging to the C. acutatum complex, including C. acutatum sensu stricto, C. fiorinae, C. godetiae, C. nymphaeae, C. salicis, and C. simmondsii. The C. nymphaeae isolates originating from symptomless weeds confirmed their pathogenicity on detached strawberry, proving that weeds in strawberry field may have a role as reservoir of inoculum. However, further studies are necessary to quantify their actual contribution to anthracnose epidemics in strawberry fields.openKarimi, Kaivan; Arzanlou, Mahdi; Pertot, IlariaKarimi, K.; Arzanlou, M.; Pertot, I

Biodiversity study of endophytic fungi associated with two Quercus species in Iran

Aim of study: In this study, frequency and diversity of fungal endophyte communities inhabiting twigs and branches of apparently healthy Q. macranthera and Q. brantii in East Azerbaijan and Lorestan provinces of Iran is presented.Area of study: East Azerbaijan and Lorestan provinces in Iran.Materials and methods: Culturable fungal endophytes were recovered from wood tissues using routine technique for isolation of fungal endophytes. The identity of fungal isolates were determined based on morphological characteristics and sequences data of ITS-rDNA region and Beta-tubulin gene. Frequency and diversity among fungal communities were analyzed using chi-square test and biodiversity indices.Main results: The highest frequency and diversity was detected for fungal endophyte community recovered from Q. macranthera and East Azerbaijan province. The assemblage of endophytic fungi characterized in this study in healthy tissues of oak trees indicates that some of the fungi are possible latent pathogens such as Biscogniauxia mediterranea with 18.28% frequency followed by Alternaria alternata and Trichothecium roseum respectively. Two fungal taxa of Pyronema domesticum and Valsa persoonii are reported for the first time in Iran. Overall, the results of this study show that the plant species and growth location influence frequency and diversity of culturable fungal endophytic communities of Quercus in Iran.Keywords: Quercus macranthera, Quercus brantii, Fungal endophytes, Molecular identification.Abbreviations used: CBS (Centraal Bureau voor Schimmelcultures); CCTU (Culture Collection of University of Tabriz); GTR (General Time Reversible); HKY (Hasegawa Kishino Yano); ITS-rDNA (Internal Transcribed Space); km (kilometer) ; PDA (Potato Dextrose Agar); TUB (Tubulin)

Biological and molecular characterisation of Pilidium lythri, an emerging strawberry pathogen in Iran

Strawberry production is hampered by numerous biotic factors including fungal pathogens. Symptoms of dark brown necrotic lesions on fruits, stems and leaves were observed in a survey of strawberry fields in the Kurdistan province of Iran. Symptomatic plant tissues were collected and several fungal isolates were recovered from these tissues. Based on a combination of morphological characteristics and sequence data for ITS and LSU ribosomal DNA, the isolates were identified as Pilidium lythri (previously named P. concavum or Hainesia lythri). A pathogenicity assay confirmed that all new isolates induced symptoms resembling those observed in the field, as well as two P. lythri isolates from olive included in the assay; no significant disease incidence or severity differences were detected between isolates. This is the first report of P. lythri on strawberry in Iran. Genetic diversity between Pilidium lythri isolates from strawberry (18 isolates) and olive (two isolates) was evaluated using RAPD and M13 markers. No polymorphism was detected within and among the isolates, indicating limited genetic variability probably due to lack of recombination events and/or recent introduction. Given recent outbreaks and the presence of the pathogen in most strawberry growing areas in the Kurdistan province, quickly applied and appropriate management programmes are necessary to prevent spread of the disease

Development of novel species-specific primers for the specific identification of Colletotrichum nymphaeae based on conventional PCR and LAMP techniques

Colletotrichum nymphaeae is the primary causal agent of strawberry anthracnose in Iran resulting in epidemics in strawberry fields in recent years. Due to the hemibiotrophic nature of the pathogen, early detection in symptomless, infected plants, especially in nurseries could be advantageous for disease management. Assessing inter-species variation by rep-PCR fingerprinting of Colletotrichum spp. within the C. acutatum species complex causing strawberry anthracnose revealed a specific genomic segment amplified with only C. nymphaeae. The amplicon was extracted, purified and novel primer sets were developed based on conventional PCR and loop-mediated isothermal amplification (LAMP) techniques. The genus and species-specific PCR primers were able to discriminate the genus Colletotrichum and C. nymphaeae from other fungal species in pure culture and in assays of diseased, detached leaves. Similar results were observed for LAMP, but it was more sensitive compared to the PCR assay. Using both assays, asymptomatic strawberry plants infected with C. nymphaeae strain CCTUCch32 were readily detected. These results show that the primer sets developed in this study based on conventional PCR and LAMP techniques can be effective for early detection of C. nymphaeae, which can contribute to improved control strategies for strawberry anthracnos

Ortiva top® fungicide as an alternative to Bavistin® fungicide against cercospora leaf spot of sugar beet

This study aimed at validating the combination of azoxystrobin + difenoconazole (Ortiva top®) as an alternative to carbendazim (Bavistin®) against Cercospora leaf spot of sugar beet caused by Cercospora beticola and identifying the lowest effective dosage. Experiments plots were designed as completely randomised blocks and subjected to foliar sprays of azoxystrobin + difenoconazole at three doses of 0.75, 1 and 1.25 L/ha and at the recommended dose of 0.5 kg/ha for carbendazim. The lowest effective dosage for azoxystrobin + difenoconazole fungicide was determined 1 L/ha under field condition. In this study, the optimal dosage of azoxystrobin + difenoconazole fungicide significantly reduced the disease severity (DS) compared with carbendazim fungicide and untreated plots and significantly increased the yield per hectare. Inclusion of the optimal dosage of azoxystrobin + difenoconazole in the cercospora leaf spot management can offer an appropriate alternative to carbendazim even under high inoculum pressure of the pathoge

Characterization of the Mechanism of Action of <i>Serratia rubidaea</i> Mar61-01 against <i>Botrytis cinerea</i> in Strawberries

Several bacterial strains belonging to Serratia spp. possess biocontrol capability, both against phytopathogens and human pathogenic species, thanks to the production of secondary metabolites, including as a red-pink, non-diffusible pigment, 2-methyl-3-pentyl-6-methoxyprodiginine (prodigiosin). Botrytis cinerea is the causal agent of gray mold, which is an economically relevant disease of many crops worldwide. Gray mold is normally controlled by chemical fungicides, but the environmental and health concerns about the overuse of pesticides call for environmentally friendly approaches, such as the use of biocontrol agents. In this study, the efficacy of a specific strain of Serratia rubidaea (Mar61-01) and its metabolite prodigiosin were assessed against B. cinerea under in vitro and in vivo conditions. This strain was effective against B. cinerea, and the effect of prodigiosin was confirmed under in vitro and in vivo conditions. The strain suppressed mycelial growth of B. cinerea (71.72%) in the dual-culture method. The volatile compounds produced by the strain inhibited mycelial growth and conidia germination of B. cinerea by 65.01% and 71.63%, respectively. Efficacy of prodigiosin produced by S. rubidaea Mar61-01 on mycelial biomass of B. cinerea was 94.15% at the highest concentration tested (420 µg/mL). The effect of prodigiosin on plant enzymes associated with induction of resistance was also studied, indicating that the activity of polyphenol oxidase (PPO), superoxide dismutase (SOD) and phenylalanine ammonia lyase (PAL) were increased when prodigiosin was added to the B. cinerea inoculum on strawberry fruits, while catalase (CAT) and peroxidase (POD) did not change. In addition, the volatile organic compounds (VOCs) produced by S. rubidaea Mar61-01 reduced mycelial growth and inhibited conidial germination of B. cinerea in vitro. The findings confirmed the relevant role of prodigiosin produced by S. rubidaea Mar61-01 in the biocontrol of B. cinerea of strawberries, but also indicate that there are multiple mechanisms of action, where the VOCs produced by the bacterium and the plant-defense reaction may contribute to the control of the phytopathogen. Serratia rubidaea Mar61-01 could be a suitable strain, both to enlarge our knowledge about the potential of Serratia as a biocontrol agent of B. cinerea and to develop new biofungicides to protect strawberries in post-harvest biocontrol

Biodiversity study of endophytic fungi associated with two Quercus species in Iran

Aim of study: In this study, frequency and diversity of fungal endophyte communities inhabiting twigs and branches of apparently healthy Q. macranthera and Q. brantii in East Azerbaijan and Lorestan provinces of Iran is presented.Area of study: East Azerbaijan and Lorestan provinces in Iran.Materials and methods: Culturable fungal endophytes were recovered from wood tissues using routine technique for isolation of fungal endophytes. The identity of fungal isolates were determined based on morphological characteristics and sequences data of ITS-rDNA region and Beta-tubulin gene. Frequency and diversity among fungal communities were analyzed using chi-square test and biodiversity indices.Main results: The highest frequency and diversity was detected for fungal endophyte community recovered from Q. macranthera and East Azerbaijan province. The assemblage of endophytic fungi characterized in this study in healthy tissues of oak trees indicates that some of the fungi are possible latent pathogens such as Biscogniauxia mediterranea with 18.28% frequency followed by Alternaria alternata and Trichothecium roseum respectively. Two fungal taxa of Pyronema domesticum and Valsa persoonii are reported for the first time in Iran. Overall, the results of this study show that the plant species and growth location influence frequency and diversity of culturable fungal endophytic communities of Quercus in Iran.Keywords: Quercus macranthera, Quercus brantii, Fungal endophytes, Molecular identification.Abbreviations used: CBS (Centraal Bureau voor Schimmelcultures); CCTU (Culture Collection of University of Tabriz); GTR (General Time Reversible); HKY (Hasegawa Kishino Yano); ITS-rDNA (Internal Transcribed Space); km (kilometer) ; PDA (Potato Dextrose Agar); TUB (Tubulin)

Characterizations of tree-decay fungi by molecular and morphological investigationsin aniranian alamdardeh forest

Forest trees are considered important in ameliorating climate change through removing carbon dioxide from the atmosphere, for stabilizing water catchments and for timber production. Wood decay fungi are among the most important biotic factors in ecosystems, infecting valuable landscaping trees causing an economic loss or the preeminent recyclers of the wood. In a survey of forest trees in the Alamdardeh forest, northern Iran, fungal fruit bodies were collected and isolations made. Based on a combination of macro-morphological characteristics and molecular analyses, using the sequence data of ITS-rDNA, isolates were identified to the species level. A total of 22 species in nine families and 15 genera were identified. Most isolates were the white-rot fungi. Additionally, the brown-rot fungus Laetiporus sulphureus and the soft-rot species Xylaria longipes were indentifie