Showing papers by "Ray A. Bressan published in 1999"

An Improved RNA Isolation Method for Plant Tissues Containing High Levels of Phenolic Compounds or Carbohydrates

Abstract: Difficulties extracting high-quality RNA from recalcitrant plant tissues are often due to high levels of phenolics, carbohydrates, or other compounds that bind and/or co-precipitate with RNA. We describe here a method using soluble polyvinylpyrrolidone (PVP) and ethanol precipitation, which has been successful in several recalcitrant systems where other specialized RNA extraction methods failed to deliver suitable product. Using this method, RNA capable of reverse-transcription/PCR amplification and cDNA library construction was isolated from ripening grape berries, dry seeds of Albizia procera and radish, and leaf tissue of A. procera and Griffonia simplicifolia. This method is applicable to a variety of plant tissues.

Isolation and characterisation of wheat cDNA clones encoding PR4 proteins.

Abstract: Two cDNA clones encoding the previously characterised PR4 proteins wheatwin 1 and wheatwin2 from wheat (Triticum aestivum cv. S. Pastore) have been identified and named wPR4a and wPR4b, respectively. The clones have been isolated by screening a cDNA library with a specific cDNA probe obtained by RT-PCR. The wPR4a and wPR4b cDNAs contain open reading frames of 441 and 447 bp that encode for wheatwin1 and wheatwin2, respectively.

Efficient plant regeneration of native spearmint (Mentha spicata L.)

Abstract: Protocols and media constituents for efficient in vitro plant regeneration of Native Spearmint (Mentha spicata L. cultivar ‘Native Spearmint’) have been defined. Adventitious shoots were initiated either directly from morphogenetically competent cells of explants or primary callus. Leaf explants from at least 2-mo.-old in vitro-maintained shoots exhibited the greatest morphogenetic capacity. Explants derived from basal portions of leaves at the bottom of the shoot were most responsive, with up to a 100% regeneration frequency and greater than nine shoots per explant. Highest frequency of meristemoids and morphogenetic callus were initiated from explants cultured onto a basal medium containing Murashige and Skoog (MS) salts, supplemented with 4 mg thidiazuron (TDZ) per L and 25% (vol/vol) coconut water (CW) for 10 to 14 d in darkness. Bud and shoot development required removal of both TDZ and CW from the medium. Shoot propagules were transferred to basal medium supplemented with 0.01 mg α-naphthaleneacetic acid (NAA) per L and grown under low light for about 2 wk to facilitate shoot elongation. Individual shoots about 1 cm tall were dissected and retransferred onto the same medium. Root initiation began within 4 to 6 d and a functional root system developed within 2 to 3 wk. These plantlets were transferred to soil and acclimated successfully for growth and development in a greenhouse. This is the first report of an efficient regeneration system for Native Spearmint based on adventitious organogenesis.

Pathogenesis-related proteins for the control of fungal diseases of tomato

Abstract: Constitutive expression of genes encoding pathogenesis related (PR) proteins is one of the strategies proposed to obtain a broad and durable level of resistance to different phytopathogenic fungi In view of this, we analyzed the response to fungal infections of transgenic tomato plants overexpressing tobacco PR-5, PR-1 and chitinase genes Constitutive expression of the PR-5 protein osmotin was correlated with increased resistance to grey mold, powdery mildew and late blight, confirmed up to the T3 generation Co-expression of more than one PR- gene in the same genome might represent a further advantage We have constructed plant expression vectors of pUC 19 derivatives that can be inserted into the cloning sites of plant transformation vectors for co-expression of up to three genes To evaluate the use of the vectors, three target gene (PR-1, chitinase and osmotin) cassettes were constructed Preliminary results from molecular analyses and infections with pathogens of transgenic plant material, indicate that these vectors can be used for co-transformation of multiple target genes Additional improvements would involve the use of different promoters and/or genes encoding proteins with higher synergistic antifungal activity