Naz, a resistant cultivar on bean root rot disease in Zanjan province, northwest Iran

Field bean is a major crops in different parts of northwest Iran especially Zanjan province. Recently the bean plants were severely subjected to damping off or decline disease which caused yield losses in bean growing regions. A regional research was done from 2003 to 2005 to get general information on the causal agent of disease and its control management. Infected plants were collected from different studied areas and transferred to laboratory. Crown and plant roots were cultured in PDA as common media and PPA as selective media for Fusarium species after surface sterilization with sodium hypochlorite. Plates were incubated in standard culture room then isolated fungi were identified. Different Fusarium species were isolated, however the main pathogen isolated from plant samples and soil around the roots was F. sambucium Fuckel. The disease caused up to 50% yield losses in some fields in studied areas. Study showed the "Naz" cultivar was the main resistant race to the disease and had the most yield production in the field.     

Biological control of strawberry crown rot,root rot and grey mould by the beneficial fungus Aureobasidium pullulans

Utilization of biocontrol agents is a sustainable approach to reduce plant diseases caused by fungal pathogens. In the present study, we tested the effect of the candidate biocontrol fungus Aureobasidium pullulans (De Bary) G. Armaud on strawberry under in vitro and in vivo conditions to control crown rot, root rot and grey mould caused by Phytophthora cactorum (Lebert and Cohn) and Botrytis cinerea Pers, respectively. A dual plate confrontation assay showed that mycelial growth of P. cactorum and B. cinerea was reduced by 33–48% when challenged by A. pullulans as compared with control treatments. Likewise, detached leaf and fruit assays showed that A. pullulans significantly reduced necrotic lesion size on leaves and disease severity on fruits caused by P. cactorum and B. cinerea. In addition, greenhouse experiments with whole plants revealed enhanced biocontrol efficacy against root rot and grey mould when treated with A. pullulans either in combination with the pathogen or pre-treated with A. pullulans followed by inoculation of the pathogens. Our results demonstrate that A. pullulans is an effective biocontrol agent to control strawberry diseases caused by fungal pathogens and can be an effective alternative to chemical-based fungicides.

     

Occurrence of crown gall disease on Ficus benjamina in Fars and Isfahan provinces of Iran

Ficus benjamina, commonly known as weeping fig, Benjamin’s fig or Ficus tree is a species of flowering plant in the family of Moraceae. It is native to south and south-east Asia and Australia. Crown gall tumours were collected from branches of one-year-old weeping fig (F. benjamina L.) trees. A total of 50 strains of Agrobacterium tumefaciens were isolated from diseased Ficus plants and their morphological, molecular and biochemical characteristics were studied; pathogenicity tests on tomato, F. benjamina and Bryophyllum daigremontianum were also conducted. Based on the biochemical characteristics, pathogenicity test and PCR amplification of 730?bp fragment using VCR\VCF primers, the tested bacterial strains were identified as A. tumefaciens. This is the first report of crown gall on F. benjamina in Isfahan and Fars provinces of Iran.     

Susceptibility assessment of bell pepper genotypes to crown and root rot disease

Bell Pepper (Capsicum annuum) is one of the important vegetable crops with valuable food sources, which is used almost around the world. Crown and root rot disease caused by Phytophthora capsici is one of the most important diseases of bell pepper in Iran. The present study was conducted to evaluate the susceptibility of different varieties of bell pepper to crown and root rot disease under glasshouse condition. Fourteen commonly planted genotypes of bell pepper in Iran were evaluated for their susceptibility to infection with the pathogen. For this purpose, disease severity of the chosen genotypes in different growth stages was evaluated. The results indicated that the bell pepper genotypes respond differently to pathogenicity tests. Based on cluster analyses confirmed by the results of SAS analyses, bell pepper cultivars were categorised in five distinct groups.     

Cadmium decreases crown root number by decreasing endogenous nitric oxide,which is indispensable for crown root primordia initiation in rice seedlings

Cadmium (Cd) is toxic to crown roots (CR), which are essential for maintaining normal growth and development in rice seedlings. Nitric oxide (NO) is an important signaling molecule that plays a pivotal role in plant root organogenesis. Here, the effects of Cd on endogenous NO content and root growth conditions were studied in rice seedlings. Results showed that similar to the NO scavenger, cPTIO, Cd significantly decreased endogenous NO content and CR number in rice seedlings, and these decreases were recoverable with the application of sodium nitroprusside (SNP, a NO donor). Microscopic analysis of root collars revealed that treatment with Cd and cPTIO inhibited CR primordia initiation. In contrast, although SNP partially recovered Cd-caused inhibition of CR elongation, treatment with cPTIO had no effect on CR elongation. l-NMMA, a widely used nitric oxide synthase (NOS) inhibitor, decreased endogenous NO content and CR number significantly, while tungstate, a nitrate reductase (NR) inhibitor, had no effect on endogenous NO content and CR number. Moreover, enzyme activity assays indicated that treatment with SNP inhibited NOS activity significantly, but had no effect on NR activity. All these results support the conclusions that a critical endogenous NO concentration is indispensable for rice CR primordia initiation rather than elongation, NOS is the main source for endogenous NO generation, and Cd decreases CR number by inhibiting NOS activity and thus decreasing endogenous NO content in rice seedlings.     

Fusarium species associated with Wheat crown and root tissues in the Eastern Iran

From 2012 to 2014, 70 isolates of Fusarium species were recovered from the wheat fields of Khosf, Giuk, Taqab, Amirabad, Mohammadieh and Bojd in the South Khorasan Province, Eastern Iran. Based on morphological characteristics, these isolates belonged to 14 Fusarium species. DNA of 23 isolates was extracted and their ribosomal ITS regions were amplified, sequenced and aligned with Fusarium species sequences of the GenBank. Among Fusarium isolates, the isolates belonging to F. solani (18.6%), F. acuminatum (12.9%), F. longipes (11.4%) and F. nygamai (10%) species had the higher frequencies. Other isolates from wheat crown and root were F. avenaceum, F. compactum, F. crookwellense, F. culmorum, F. diversisporum, F. equiseti, F. fujikuroi, F. javanicum, F. oxysporum and F. semitectum. This study is the first investigation of Fusarium species associated to wheat crown and root in the eastern desert area of Iran.     

Effects of inoculum density and substrate type on saprophytic survival of Phytophthora drechsleri, the causal agent of gummosis (crown and root rot) on pistachio in Rafsanjan, Iran

In this study, sampling was carrid out on soils around pistachio trees in various regions of Rafsanjan, Iran. Following isolation and identification of Phytophthora isolates, the predominant species was found to be P. drechsleri and used for further investigation. For studying saprophytic survival of the fungus, soils collected from different areas were combined and autoclaved. Sterile soil was divided into 10 parts and mixed with fungal inoculum at various concentrations of 0-9% (w/w) separately. Each soil part (100g) was placed in 15cm diameter plastic pot. Some soils in pots were supplemented with sterile wheat straw whereas others were mixed with pistachio leaves surface sterilized with 5% (v/v) sodium hypochlorite. After 3, 6 and 9 weeks of incubation, five leaves or straws samples were taken from each replicate and cultured on CMA-PARPH medium and the fungal colony formation was monitored. The experiment was performed using completely randomized design with factorial experiments including three factors (substrate type, inoculum density and time), 10 treatments (0-9 g inoculum levels) and nine replicates. The results showed that the type of substrate (wheat straw and pistachio leaf) was very important for the fungal saprophytic survival in that this was significantly greater for the pistachio leaves. Time was also considered another critical factor for the fungal survival. With passing incubation time, saprophytic survival of the fungus declined. Further, it was demonstrated that increasing inoculum density would result in longer survivability of P. drechsleri and maximum fungal survival on substrate was obtained when inoculum density was at 9% (w/w).     

Induction of systemic resistance against Fusarium crown and root rot disease by blast processing

The effect of fan-forced wind on the severity and growth of Fusarium oxysporum f. sp. radicis-lycopersici (FORL) was examined in this study. The discoloration severity of the total root system was significantly reduced in plants treated with air blasting for 30?min at a wind speed of 4?m/s compared with the control. In addition, the number of colony-forming units of FORL per gram of fresh root weight was significantly reduced (p?≤?0.05) in plants treated with air blasting at a wind speed of 4?m/s for 30?min, and the root extracts of these plants had a significantly lower production of FORL budding cells. Booster wind treatments significantly reduced the severity and growth of FORL compared with single and control treatments. Furthermore, RT-PCR analysis indicated that the expression of defense-related genes was induced in the leaves of seedlings treated with air blasting at a wind speed of 4?m/s.     

Evaluation of Anti-Toxoplasma IgG, IgM, and IgA in Mothers with Spontaneous Abortion in Zanjan, Northwest Iran

Toxoplasma gondii is one of the major agents of infectious abortions and due to its worldwide distribution can threat healthy pregnant women who had no previous exposure to this parasite. The present study was designed to investigate the contribution of T. gondii to spontaneous abortions in Zanjan, Northwest of Iran, using ELISA method. Blood Samples were collected from 264 mothers referred to the provincial hospitals of Zanjan due to spontaneous abortion. The sera were isolated and subjected to evaluate the anti-Toxoplasma IgG, IgM and IgA antibodies. The results showed IgG positive (IgG⁺) in 99 cases (37.5%). A total of 68 women (25.8%) showed seroconversion with IgM or IgA or both IgM and IgA. They included: IgM⁺ in 21 (8.0%), IgA⁺ in 23 (8.7%) and both IgM⁺ and IgA⁺ in 24 (9.1%) subjects. In 23 cases, positive titers of IgM and IgG were accompanied. In general, the analysis of anti-Toxoplasma antibody patterns, showed that about 17% of the spontaneous abortions were associated with serological patterns of acute infection. According to these findings, a considerable proportion of spontaneous abortions can be attributed to T. gondii in the study area.     

CRD1, an Xpo1 domain protein,regulates miRNA accumulation and crown root development in rice

Crown root (CR) is the main component of the fibrous root system in cereal crops, but the molecular mechanism underlying CR development is still unclear. Here, we isolated the crown root defect 1 (crd1) mutant from ethyl methane sulfonate‐mutated mutant library, which significantly inhibited CR development. The CRD1 was identified through genome resequencing and complementation analysis, which encodes an Xpo1 domain protein: the rice ortholog of Arabidopsis HASTY (HST) and human exportin‐5 (XPO5). CRD1 is ubiquitously expressed, with the highest expression levels in the CR primordium at the stem base. CRD1 is a nucleocytoplasmic protein. The crd1 mutant contains significantly reduced miRNA levels in the cytoplasm and nucleus, suggesting that CRD1 is essential for maintaining normal miRNA levels in plant cells. The altered CR phenotype of crd1 was simulated by target mimicry of miR156, suggesting that this defect is due to the disruption of miR156 regulatory pathways. Our analysis of CRD1, the HST ortholog identified in monocots, expands our understanding of the molecular mechanisms underlying miRNA level and CR development.     

Rhizospheric bacteria as potential biocontrol agents against Fusarium wilt and crown and root rot diseases in tomato

The discovery of novel biocontrol agents requires the continuous scrutiny of native microorganisms to ensure that they will be useful on a regional scale. The goal of the present work was to discover novel antagonistic bacteria against Fusarium oxysporum ff. spp. lycopersici race 3 (Fol R3) and radicis-lycopersici (Forl) causing Fusarium wilt disease and Fusarium crown and root rot of tomatoes, respectively. High-throughput liquid antagonism screening of 1,875 rhizospheric bacterial strains followed by dual confrontation assays in 96-well plates was used to select bacteria exhibiting > 50% fungal growth inhibition. In a second dual confrontation assay in 10-cm Petri dishes, bacteria showing > 20% Fol R3 or Forl growth inhibition were further screened using a blood hemolysis test. After discarding β-hemolytic bacteria, a seedling antagonistic assay was performed to select five potential antagonists. A phylogenetic analysis of 16S rRNA identified one strain as Acinetobacter calcoaceticus (AcDB3) and four strains as members of the genus Bacillus (B. amyloliquefaciens BaMA26, Bacillus siamensis BsiDA2, B. subtilis BsTA16 and B. thuringiensis BtMB9). Greenhouse assays demonstrated that BsTA16 and AcDB3 were the most promising antagonists against Fol R3 and Forl, respectively. Pathogen biocontrol and growth promotion mechanisms used by these bacteria include the production of siderophores, biofilm, proteases, endoglucanases and indole acetic acid, and phosphate solubilization. These five bacteria exerted differential responses on pathogen control depending on the tomato hybrid, and on the growth stage of tomatoes. We report for the first time the use of an Acinetobacter calcoaceticus isolate (AcDB3) to control Forl in tomato under greenhouse conditions.     

Biodiversity of vespid wasps in spatial and temporal dimensions in northern Zanjan Province of Iran

Vespidae is one of the major families of Hymenoptera with more than 115000 described species. In the present paper, Simpson and Shannon-Wiener diversity indices, Simpson,Camargo, Smith and Wilson, and modified Nee evenness indices, and richness index based on rarefaction method were adopted to study the biodiversity of vespid wasps in spatial and temporal dimensions in northern Zanjan Province of Iran. In spatial dimension, Zanjan and Gilvan showed the highest and the lowest species diversity, evenness, and richness, respectively; while in tem-poral dimension, 16 July-6 August showed the highest species diversity and richness, and 18 May -27 May and 23 August -2 September showed the highest and the lowest species evenness,respectively. Significant differences in species abundance between localities of study area were observed by Kruskal-Wallis nonparametric test.     

The epidemiology of tomato brown root rot

In the absence of nematodes, three different symptoms of disease, parts of the brown root rot complex (BRR), occurred on tomato roots surviving in soils infested with GSF (= grey sterile fungus) and Colletotrichum atramentarium (Berk. & Br.) Taubenh. In heavily infested soils brown lesions occurred throughout cropping, appearing within a week of planting. Corkiness and black dot, caused by GSF and C. atramentarium respectively, rarely occurred until the third month after planting but towards the end of the season the incidence of black dot sometimes suddenly increased greatly. Observations of crops growing in plots treated with different soil partial sterilants suggested that GSF was more damaging than C. atramentarium. Yield was not related to the incidence of black dot but was inversely proportional to the occurrences of brown lesions and corkiness. The relation with brown lesions was significant within 8 weeks of planting, when most brown lesions gave cultures of GSF, but later more of these lesions gave cultures of C. atramentarium than of GSF. Pathogenicity tests with pure cultures of GSF and C. atramentarium were done on agar media and by artificially infesting partially sterilized soils. Roots of undamaged seedlings on agar media developed 10 mm. brown lesions within 2 weeks of inoculating 10-day-old tomatoes with most GSF cultures isolated from: (1) rotted roots of Lycopersicon esculentum, Solanum capsicastrum, Capsicum annuum var. longum and C. frutescens; (2) browned zones of Lycopersicon hirsutum roots; and (3) apparently healthy roots of Cucumis sativus. After inoculation with C. atramentarium, small (c. 2 mm.) pink lesions developed, whereas none formed using Pyrenochaeta spp. In soil tests the greater root damage done by GSF, including root loss, was reflected in decreased aerial growth and smaller fruit yields; C. atramentarium affected neither. In the second year of soil infestation GSF decreased yields during 6 weeks of picking from 1.96 kg. in the uninoculated controls to 1.02 kg./plant. The pattern of damage done by GSF changed as plants aged. In soil, brown lesions occurred within a few days of planting but corkiness did not appear for 2–3 months, when stem lesions and leaf yellowing often developed simultaneously. A 50% root loss after 21 weeks did not affect fruit yields whereas a 40% loss within 11 weeks of planting was reflected by a 45% yield decrease.     

Biocontrol of Rhizoctonia crown and root rot of sugar beet by binucleate Rhizoctonia spp. and Laetisaria arvalis

Two isolates of Laetisaria arvalis and 10 of binucleate Rhizoctonia spp. (BNR) from the Ohio sugar beet production area, were tested in the greenhouse and field for biocontrol of Rhizoctonia crown and root rot of sugar beet, caused by Rhizoctonia solani anastomosis group 2, type 2. L. arvalis was ineffective in standard greenhouse tests, and the single isolate used in the field was generally ineffective. Seven of 10 BNR isolates effectively controlled crown and root rot in greenhouse tests. Delayed application of biocontrol agents to plants 5 – 10 wk old was generally more effective than applications made at planting. A BNR isolate significantly reduced % plant loss and disease ratings and increased yield in a 1985 field test as compared with the control infested with R. solani alone. Two BNR isolates were effective in a 1986 field test and increased yields c. 22% in comparison to a L. arvalis treatment, which did not differ from the R. solani-infested control. The Ohio binucleate Rhizoctonia isolates appear to have considerable potential as applied biocontrol agents and may play a role in the natural ecology of R. solani in the sugar beet production area of Ohio.     

The effect of chemical and biological treatment on root and crown rot disease caused by Phytophthora cryptogea Pethybr. & Lafferty in Gerbera

Phytophthora root and crown rot (Phytophthora cryptogea) on gerbera is difficult to manage because most gerbera cultivars are susceptible to P. cryptogea. This study was conducted in order to determine the in vivo (pot experiment) efficacy of some fungicides and biofungicides. In pot experiments, fungicides were applied 7 days after inoculation with P. cryptogea, while biofungicide was applied 7 days before inoculation. In this study, soil drenches of five fungicides were tested. “Ametoctradin+dimethomorph (100 ml/day),” “mandipropamid+difenoconazole (60 ml/day),” “propamocarb+fosetyl‐Al (200 ml/day),” “mancozeb+metalaxyl‐M (250 g/day)” and “azoxystrobin+difenoconazole (100 ml/day)” active substances were used. Similarly, one biofungicide Bacillus amyloliquefaciens syn. MBI 600 (50 g/100 L) was applied by soil drenching. Efficacy of treatments was assessed according to the percentage of the root system which was visibly rotten at the end of the experiment. Root and crown rot severity was rated on a scale of 0 = 0% root system necrotic, 1 = 1%‐25% necrotic, 2 = 26%‐50% necrotic, 3 = 51%‐75% necrotic and 4 = 76%‐100% necrotic from 12 to 21 days. In this experiment, “azoxystrobin 200 g/L + difenoconazole 125 g/L” exhibited the highest efficacy against P. cryptogea with a ratio of 43.75%. The other fungicides and biofungicides ametoctradin 300 g/L + dimethomorph 225 g/L, mandipropamid 250 g/L + difenoconazole 250 g/L, propamocarb 530 g/L + fosety‐Al 310 g/L, mancozeb 64%+metalaxyl‐M 4% and Bacillus amyloliquefaciens syn. MBI 600 11% were ineffective. Importance should be given to management strategies of P. cryptogea of and more experiments should be carried out for a better understanding of the use of registered fungicides and biofungicides.     

Phenotypic analysis of adults of Fasciola hepatica, Fasciola gigantica and intermediate forms from the endemic region of Gilan, Iran

Fascioliasis is an important human and animal disease caused by Fasciola hepatica and Fasciola gigantica. In Iran, the distribution of these two species overlaps in most areas, including the northern human endemic province of Gilan where both fasciolids are simultaneously found in individual cattle and buffaloes. A phenotypic study of fasciolid adult flukes from naturally infected bovines from Gilan was carried out by means of an exhaustive morphometric analysis using traditional microscopic measurements and an allometric model. The Iranian fasciolids were compared to F. hepatica and F. gigantica standard populations, i.e. from geographical areas where both species do not co-exist (Bolivia and Burkina Faso, respectively). Although morphometric values somewhat overlapped, there were clear differences in allometric growth. The allometric function was adjusted to 25 pairs of variables. Results obtained revealed that Iranian F. hepatica-like specimens are larger than the F. hepatica standard and Iranian F. gigantica-like specimens are longer and narrower than the F. gigantica standard, but with smaller body area. Measurements which permit a specific differentiation in allopatric populations (distance between ventral sucker and posterior end of the body; ratio between body length and body width) overlap in the specimens from Gilan, thus proving the presence of intermediate forms. When compared to the standard populations, the different Iranian fasciolid morphs show greater differences in F. gigantica-like specimens than in F. hepatica-like specimens. This study shows that simple, traditional microscopic measurements may be sufficient for the morphometric characterisation of fasciolids, even in areas where intermediate forms are present.     

Brown root rot of tomato, and its control, in Crete

Symptoms similar to those regarded as typical of brown root rot disease have been noticed in tomato and eggplant in Crete. Infected plants showed symptoms only during the winter. Three fungi Pyrenochaeta lycopersici, Colletotrichum coccodes and Fusarium oxysporum were consistently isolated from infected tomato roots and proved to be pathogenic to young tomato seedlings. Pycnidia of P. lycopersici were produced when small pieces of infected young tomato roots were plated out on tomato juice agar (Oxoid) and incubated at 23 °C under continuous white light. Good control of the disease was achieved when soil was fumigated with dazomet 98% (70g/m²), methyl isothiocyanate (MIC) 20%+ dichloropropane-dichloropropene mixture (DD) 80% (-Di-Trapex; 50 ml/m²), methyl bromide (75 g/m²), and vapam (200 ml/m²) + ethoprophos 10% (10 g/m²) or when solarisation was applied (soil covered by 50 μm transparent polyethylene sheet) during the whole period of August and September. Dazomet (30 g/m²) or ethoprophos 10% (10 g/m²) when combined with solarisation did not improve its effectiveness. MIC 20%+ DD 80% emulsified (Di-Trapex e.c, 50 ml/m²) was ineffective.     

Antagonistic effects of several bacteria on Fusarium oxysporum, the causal agent of root and crown rot of onion under field conditions

Onion (Allium cepa) is one of the most important vegetable crop which is commonly used as a food supplement. This plant is found to be vulnerable to various pathogenic infections during its growth development. Among different onion diseases, root and crown rot,caused by Fusarium oxysporum f.sp. cepa, s considered an importantfungal disease. In this study, the inhibitory effect of Bacillus cereus (isolates 22 and 52), B. subtilis (isolate 126), Pseudomonas fluorescens (isolates 48 and CHAO), benomyl fungicide and a combination of isolates CHAO and 22 and isolate 52 and benomyl were investigated on disease development under the field condition. This experiment was carried out in a randomize complete blocks with 10 treatments and three repetitions. Grouping of treatments was done at 5% level using Duncan multiple comparison test. It was also demonstrated that isolate 126 was the most effective antagonist with regard to crop yield but other treatments despite showing significant on plant growth factors were less effective in increasing crop yield.     

Distribution and health risk assessment of heavy metals in soil surrounding a lead and zinc smelting plant in Zanjan,Iran

One of the problematic issues in soil pollution studies is heavy metal particles which are produced by mines and smelting units and spread through wind action and/or runoff. Pollution and health risk assessment of cadmium, lead, zinc, copper, and nickel in soil around the lead and zinc smelting factory was carried out in Zanjan City, Iran. Contamination factor (Cf), pollution load index (PLI), geoaccumulation index (Igeo), hazard quotient (HQ), hazard index (HI), and carcinogenic risk were pollution and human health risk assessment metrics in this study. Based on the Iranian soil guideline value, soil samples in the studied areas were contaminated the least by copper and nickel and the most by cadmium. PLI results showed that soils near the production line were heavily or extremely heavily polluted. The results of Cf and Igeo showed that lead and zinc were the most important contaminants. Health risk assessment indicated that lead and cadmium in soil were the main contaminants, which pose both carcinogenic and non-carcinogenic risks to human health; carcinogenic risk levels were unacceptably high (above 1 × 10^?4). It can be concluded that mining and smelting activities degrade soil quality in this region and the soil pollution might be extended to farming areas.