Crown gall caused by Agrobacterium spp. has been observed in various crop species and in several provinces of Iran in recent years. In an attempt to identify the Agrobacterium species causing the disease in different areas of the country, strains were isolated from various infected crop species and characterized by phenotypic features, electrophoretic profile of cell proteins and BOX IR fingerprinting.On the basis of their phenotypic features, the strains were differentiated into three separate groups. The phenotypic characteristics of the first group of strains were closely similar to those of A. tumefaciens (Rhizobium tumefaciens). Members of the second group, isolated from infected grapevines were also identified as A. tumefaciens. Strains of the third group were phenotypically different from all described species, but appeared to be more similar to A. tumefaciens. These strains were not able to grow on any of the selective media tested and displayed a limited host range, infecting mainly sweet cherry All strains had a similar plasmid profile. The electrophoretic profile of cell proteins of the strains was different, although some similarity of the pattern was noted in the high-molecular weight region. In fingerprinting using BOX IR primer, a high level of heterogeneity was observed, nonetheless two major groups were differentiated. Phenotypic features appeared to be reliable criteria in identification of Agrobacterium species encountered in this study.

During the years 1997-1998, thirty-one Agrobacterium isolates were obtained from gall and sap of infected grapes as well as from soil in vineyards of Fars and Kohkilouyeh and Boyerahmad province. Two pathogenic and one non- pathogenic isolates of Agrobacterium tumefaciens Biovar1 were selected and their cell protein patterns compared through gel electrophoresis. A pathogenic and one non- pathogenic isolate of A. vitis and A. tumefaciens Biovar1 were selected from which antisera were prepared. Serological studies based on agar gel diffusion placed bacterial isolates in 4 serogroups while slid agglutination test placed the isolates in 6 sergroups. A comparison of cell proteins pattern showed that A. vitis and A. tumefaciens Biovar1 isolates were heterogenous, even though similar protein bands existed among the isolates.

Aims: Improvements in nanotechnology in the past decayed has created various opportunities for evaluation of biologic effects such as anti-bacterial effects of nanoparticles. The purpose of this study was to evaluate the antibacterial activity of calcium carbonate nanoparticles on two different bacteria including Agrobacterium tumefaciens and Staphylococcus aureus.Methods: The antibacterial effect of calcium carbonate nanoparticles against mentioned bacteria was evaluated by dilution in agar containing medium and dilution in Broth medium. Each of prepared Broth Media (10 ml) was inoculated with 1 ml of bacterial suspension (106 CFU/ml) and incubated. Sampling of culture Media was performed in specific intervals and diluted as 10-1, to 10-6. Then 100 ml of each sample was transferred to agar plates and was spread carefully and then incubated. Grown colonies were counted and MIC and MBC was determined.Results: Calcium carbonate nanoparticles showed very good antibacterial effect and after 16 hours the bacteria were totally diminished. The lowest and highest MIC concentration of these nanoparticles in solid medium was 31.2 and 125 mg/ml respectively. The MIC of calcium carbonate nanoparticles in Broth Medium was two times more than the MIC concentration in solid medium, while different concentrations of ordinary calcium carbonate not only revealed antibacterial effects but also supported the bacterial growth.Conclusion: Use of calcium carbonate nanoparticles as an anti-microbial agent is recommended in different fields of medicine, food industry and agriculture and can be of importance considering health and economic issues.

Stunting and declining symptoms on 3-5 year old apple trees grafted on Maling rootstocks were associated with uneven growth of root and presence of numerous thin and tender roots, similar to hairy root symptoms, on the main and lateral roots of the trees. The growth of the main root appeared to be arrested. Symptoms were observed on trees grown in two orchards in Semirom in Isfahan province and on apples grafted on Maling-Morton (MM) rootstocks in a nursery in Mashhad, Khorasan province. Segments of roots with hairyroot symptoms were thoroughly washed under tap water, rinsed in sterile distilled water (sDw), and then minced with a sterile razor blade in a few drops of SDW in a Petri plate. The suspension, following a 20-30 min standing at room temperature, was streaked onto plates of 2E and potato dextrose agar + calcium carbonate media and incubated at 25-27°C. White mucoid colonies appearing on both media after 4-5 days of incubation were isolated and used in phenotypic and genotypic characterization and identification. All isolates induced formation of copious amounts of callus on carrot root slices, but none produced any noticeable number of roots on the slices, up to one month post-inoculation. Twenty five of the 60 strains isolated were used as representatives in further characterization tests. The strains were motile, oxidase positive, and catalase positive, could grow on media containing 2% sodium chloride and at 33°C. They formed pellicle on ferric ammonium citrate and used sucrose and citrate as the sole carbon sources for growth. None produced 3-ketolactose nor utilized melezitose or malonate. In polymerase chain reaction (PCR) assays, with ipt and vir D primers, the species-specific fragments of 427 bp and 224 bp long were amplified, respectively, using from DNAs of all strains as templates. Based on the results of phenotypic tests and PCR assays, the strains belong to Agrobacterium tumefaciens (Rhizobium radiobacter). Similar root-inducing strain of A. tumefaciens have also been isolated from cucumber roots in England and named rhizogenic A. tumefaciens .

Tomato is a plant which has highly important nutrition, economic and scientific aspects. Due to its susceptibility to biotic and abiotic stresses, breeding through genetic engineering of this plant is an effective method for enhancement of its tolerance to stresses. In this experiment, factors influencing the transformation of cultivated tomato, were studied. The high shoot regeneration was observed in Peto earlyCH and Early urbanaY cultivars, respectively and the most transformation rate was obtained in Early urbanaY cultivar. Preculture of explants for 1 day and addition of 100 - 150 mM acetosyringone into inoculation solution had a positive effect on transformation efficency. The optimum inoculation and cocultivation time for explants was 15 minutes and 2 days respectively. Putative transgenic plants were confirmrd using PCR and specific primers of both genes (nptII andcodA genes). These plants were transferred to the soil for further molecular and bioassay experiments.

Brazilian peppertree (Schinus terebinthifolius) leaf extract was applied against two strains of the crown gall disease (Agrobacterium tumefaciens); strains C58 and AR125. In vitro, we used the agar well diffusion method and the extract was tested in different solvents selected according to their polarity indices, at different concentrations and different incubation temperatures. In vivo, we tested the extract prepared in different solvents on the stems of young tomato plants (cv. Firenze) which were inoculated with the strain C58.The best results were obtained with the extract prepared in hot sterile distilled water and in methanol (0.3 g.ml-1) incubated at 25 oC and 30 oC. The minimum inhibitory concentration (MIC) was evaluated to 10-4 g.ml-1. In another aspect, to identify the nature of certain substances from S. terebinthifolius leaf extracts, we made a test of fractionation using the Thin Layer Chromatography (TLC) method and phytochemical screening of the crude methanol leaf extract. We noticed the presence of alkaloids and flavonoid compounds which may be responsible for the antibacterial activity. These tests indicated that false pepper leaf extract has an antibiotic effect against Agrobacterium tumefaciens both in vitro and in vivo, which represents a conceptual approach with great promise for future biological control.

Abiotic stress conditions can be imposed on plants through either poor water quality or adverse climate condition. These types of stress affect plant growth and development throughout their life cycle. Plants that are tolerant to drought are therefore valuable, and turf grasses have the potential to grow tolerant. Turf grasses provide ground cover and offer multiple benefits, from their aesthetic value which affects our daily lives to their preservation of land against erosion. The objectives of the present work were to find the ideal media for callus induction and regeneration followed by overexpressing theP5CS1 gene encoding proline for improving drought stress resistance inFestuca arundinacea Schreb. The husks of tall fescue seeds were removed and the seeds were then sliced longitudinally. The result of this treatment showed a greater callus induction efficiency in comparison with intact seeds in the culture media. In addition, an increase in regeneration efficiency was observed in media supplemented with 2, 4-D along with BAP. The average of G418‒resistant calli obtained in the experiment was around 10%. The heterologous transformation ofP5CS1 in F. arundinacea background was confirmed by PCR and the transient Gus assay. More than 90% of calli expressed the uida gene which can most probably convey resistance to drought stress.