5S ribosomal DNA (rDNA) was visualized on the somatic metaphase chromosome of persimmon (Diospyros kaki) and ten wild Diospyros species by fluorescent in situ hybridization (FISH). The digoxigenin (DIG)-labeled 5S rDNA probe was hybridized onto the chromosomes and visualized by incubation with anti-DIG-fluorescein isothiocyanate (FITC). Strong signals of 5S rDNA probe were observed on several chromosomes of Diospyros species tested. Furthermore, multicolor FISH using 5S and 45S rDNA probes differently labeled with DIG and biotin, revealed separate localization of the two rDNA genes on different chromosomes of Diospyros species tested, suggesting that 5S and 45S rDNA sites can be used as chromosome markers in Diospyros. The number of 5S rDNA sites varied with the Diospyros species. More 5S rDNA sites were observed in four diploid species native to Southern Africa than in three Asian diploid species. The former had four or six 5S rDNA sites while the latter had two. Three Asian polyploidy species had four to eight 5S rDNA sites. Among the Asian species, the number of 5S rDNA sites seemed to increase according to ploidy level of species. These features of 5S rDNA sites were very similar to those of 45S rDNA sites in Diospyros. Phylogenetic relationship between D. kaki and wild species tested are discussed based on the number and chromosomal distribution of 5S and 45S rDNA.
Young A Choi, Ryutaro Tao, Keizo Yonemori, and Akira Sugiura
Hidemi Izumi, Takeshi Yamashita, and Maki Inada
Ferulic acid agent (2% of ferulic acid), fumaric acid agent (20% of fumaric acid), mustard extract agent (10% of allyl isothiocyanate), and calcined calcium agent (91% of calcium) were assessed for reduction of endogenous microbial population on fresh-cut lettuce, cabbage, and cucumber in the preliminary study. In seeking effective minimum concentration, a 0.5% ferulic acid agent or 1.0% fumaric acid agent applied on lettuce, 0.1% mustard extract agent on cabbage, and 0.05% calcined calcium agent on cucumber reduced mesophilic aerobic bacteria (MAB) and coliform group (coliforms) by about 0.5 to 1.5 logs relative to water-dipped control. The efficacy of these antimicrobial agents with subsequent washing treatments with electrolyzed water (13 ppm of available chlorine) or ozonated water (5 ppm of ozone) on endogenous microorganism were evaluated with fresh-cut vegetables stored in MA package for 4 days at 10 °C. With lettuce, the fumaric acid agent followed by electrolyzed water treatment was the most effective in reducing counts of MAB, coliforms, and psychrotrophic aerobic bacteria (PAB) for the first 2 days of storage. This treatment eliminated gram-positive bacteria such as the genus Curtobacterium and gram-negative bacteria such as the genus Stenotrophomonas. With cucumber, fumaric acid agent or calcined calcium agent with sequential washing with electrolyzed water reduced counts of MAB, coliforms, PAB and lactic acid bacteria during 4 days of storage, with the reduction being greater with fumaric acid agent than with calcined calcium agent. With cabbage, the combinations of the agents and washing treatments had no pronounced effect when compared with water treatment.
Bruce E. Branham, Glenn A. Hardebeck, Joseph W. Meyer, and Zachary J. Reicher
Annual bluegrass (Poa annua L.) is an invasive weed producing copious amounts of viable seed that compete with seedling turfgrasses during renovation. These field studies were conducted to determine the effectiveness of dazomet (tetrahydro-3,5-dimethyl-2H-1,3,5-thiadiazine-2-thione), a granular soil sterilant that breaks down in soil to release methyl isothiocyanate (MITC), for controlling the soil seed bank of annual bluegrass during turfgrass renovation. Field trials in Urbana, Ill., and West Lafayette, Ind., in Spring and Fall 2000 and 2001 evaluated dazomet rate from 0 to 504 kg·ha-1 and soil preparation techniques to determine the most effective practices to reduce annual bluegrass reestablishment into a creeping bentgrass (Agrostis stolonifera L.) seeding. The interval, in days, between dazomet application and creeping bentgrass planting was also examined to determine the optimal seeding time as measured by the level of annual bluegrass reestablishment. Spring trials generally gave poor results that were attributed to windy conditions resulting in rapid loss of MITC. The annual bluegrass soil seed bank was reduced 46% in spring trials compared to 78% in fall trials. Increasing dazomet rates reduced the absolute number of viable annual bluegrass seeds remaining in the soil. However, significant quantities of viable seed remained, regardless of dazomet rate. Annual bluegrass infested the renovated turf in all trials to varying degrees. Dazomet rates of 420 or 504 kg·ha-1 yielded the lowest rates of annual bluegrass reestablishment. Trials conducted in the fall at these rates resulted in annual bluegrass cover of 1% to 20% in the resulting turf. Creeping bentgrass planted at 1 day after dazomet application had significantly less annual bluegrass than when seeded at 7 or 9 days after dazomet application. Dazomet is a tool that can help reestablish a new turf with lower levels of annual bluegrass. However, eradication of annual bluegrass with dazomet is not likely and environmental conditions will dramatically affect the success of the sterilization.
Ji Yeon Kang, Khalid E. Ibrahim, Doo Hwan Kim, Wha-Jeung Kang, and John A. Juvik
Gluconasturtiin is a glucosinolate (GS) present in Chinese cabbage and its breakdown product, phenelethyl isothiocyanate (PEITC), inhibits phase I enzyme activation of endogenous carcinogenic compounds and enhances phase II enzyme detoxication, reducing cancer risk and promoting health in humans. This study was conducted to evaluate the interaction between the genotype and the environment to influence GSs in Chinese cabbage. Twenty-five accessions were grown in three environments and tissue quantified for GS levels by HPLC. While gluconasturtiin was observed to be the most abundant GS form, 3-indolylmethyl GS (glucobrassicin) and 1-methoxy-3-indolylmethyl-GS (neoglucobrassicin) were also found. Significant differences were observed among tissues, genotypes and environments in GS concentration and composition. Gluconasturtiin ranged from 0.56 μmol·g-1
DW in leaf tissue of Hau No. 2 to 11.89 μmol·g-1 DW in Chilsung. There were dramatic differences among different tissues of the same genotype with young leaf and root tissues having significantly higher concentrations of gluconasturtiin than other tissues. Gluconasturtiin in Sandong No. 5 ranged from 1.69 μmol·g-1 DW in mature leaves to 18.69 μmol·g-1 DW in root tissue. GS content of the same genotypes in three different environments indicated that plants grown in the greenhouse had higher GS content compared to field grown plants. Results of this study indicate that genotypic variation and the growing environment have substantial effects on GS content in Chinese cabbage. This investigation provides important information for future genetic and molecular studies and has identified Chinese cabbage genotypes that offer superior health benefits to consumers.
development and shuck dehiscence. Phenyl Isothiocyanate Performance as a Methyl Bromide Alternative Purple nutsedge control in vegetable crops is challenging in the absence of methyl bromide. Bangarwa et al. (p. 402) evaluated the efficacy of phenyl
Kimberly A. Cochran and Craig S. Rothrock
, crop, environment, and method of delivery. Brassicas are thought to be effective in suppression of soilborne pathogens due to the release of isothiocyanates and other chemicals produced from the hydrolysis of glucosinolates ( Fan et al., 2008
Brad Geary, Corey Ransom, Brad Brown, Dennis Atkinson, and Saad Hafez
glucosinolate concentrations that are released as pesticidal compounds (ionic thiocyanate and isothiocyanate) similar to the a.i. (methyl isothiocyanate) of the commercial fumigant metam sodium ( Bialy et al., 1990 ). The quantities, activities, and dynamics of
Sanjeev K. Bangarwa, Jason K. Norsworthy, Ronald L. Rainey, and Edward E. Gbur
, resulting in relatively higher production cost and lower yield and net returns. Therefore, there is a need to develop an effective alternative to methyl bromide in plasticulture tomato production. Volatile allelopathic compounds like isothiocyanates (ITCs
Sanjeev K. Bangarwa, Jason K. Norsworthy, and Edward E. Gbur
). Additionally, maceration of mustard family plant tissue releases a number of allelopathic compounds, including isothiocyanates ( Fahay et al., 2001 ). Isothiocyanates are biologically active compounds that prevent or delay weed emergence ( Brown and Morra, 1995
Bielinski M. Santos and James P. Gilreath
promising MBr alternatives ( Ajwa et al., 2002 ; Martin, 2003 ). The primary breakdown product of these fumigants is methyl isothiocyanate, which is a potent biocide that react with amines and thiols in biological molecules ( Duniway, 2002 ; Lam et al