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- Author or Editor: S. K. Lee x
- HortScience x
Lettuce (Lactuca sativa L.) were transformed using microparticle bombardment with two different genes, alpha-glucuronidase (GUS) gene and Chinese cabbage Glutathione Reductase (GR) gene. The adventitious shoots of cotyledonary explant from 4-day-old seedlings were formed (46.7%) in MS basal media supplemented with 5.0 μm IAA and 1.0 μm 2ip. When 1100 psi helium pressure, 9 target distance, and coating with tungsten 10 microparticles were used and explants were treated with osmoticum-conditioning medium (0.6M sorbitol/mannitol), 4 h prior to and 16 h after bombardment, it was identified by GUS assay that these conditions were the most efficient for transformation of foreign genes into cotyledon tissue of lettuce with particle bombardment. PCR confirmed that the band observed in the transgenic plants were originated from T-DNA tranfer with strong hybridization. The genomic Southern analysis showed that the 1.5-kbp fragment was hybridized with radiolabeled 1.5-kbp GR probe. To know whether the expression of the GR gene can be stably maintained in the next generation, when T2 selfing seeds that were obtained from the transformed mother plants were sowed on MS medium supplemented with 200 μm kanamycin, 70% of seedlings were revealed resistance to kanamycin.
Abstract
Callus tissues of orchid Aranda Tay Swee Eng (Archnis Lily Chong × Vanda Piha Moon) were cultured in Vacin and Went's medium that contained between 0% and 2% fructose. The chlorophyll content of callus tissues measured after 31 days of incubation ranged from 59 to 133 µg·g–1 tissue and was inversely proportional to the C/N ratio of the initial culture medium. The number of protocorm developed on callus tissue was instead inversely proportional to the residual C/N ratio of the 31-day-old culture medium and ranged from 13 to 74. The interrelationship of the C/N ratio of the medium, chlorophyll content, and protocorm formation in Aranda callus tissues is discussed.
Buffalograss [Buchloe dactyloides (Nutt.) Engelm.] has the potential for increased use as a turfgrass species due to its low maintenance and water conservation characteristics. This study was conducted to estimate diversity and relationships among naturally occurring buffalograss genotypes based on the nuclear genome, using sequence-related amplified polymorphism (SRAP) markers. The 56 genotypes studied represented five ploidy levels collected from diverse geographic locations in the North American Great Plains. In addition, blue grama [Bouteloua gracilis (H.B.K.) Lag. Ex Steud.] and perennial ryegrass (Lolium perenne L.) were included as outgroups. Twenty-five combinations of forward and reverse primers were used. Ninety-five intensively amplified markers were scored and used to infer diversity and relationships among the genotypes. All buffalograss genotypes were discriminated from each other with similarity values ranging from 0.70 to 0.95. Principal component analysis (PCA) suggested that the 56 genotypes could be reduced to 50 due to high similarity levels among some of the genotypes. The distance between buffalograsses, blue grama, and perennial ryegrass were consistent with current taxonomical distances. This research indicates that SRAP markers can be used to estimate genetic diversity and relationships among naturally occurring buffalograss genotypes.