Isolation and culture of grapevine protoplasts

Methods were established for isolation of protoplasts from different organs and tissues of grapevine plants grown in vitro. Cell division could not be induced in protoplasts from leaves, shoot tips and petioles of cv. Optima, whereas stein and root protoplasts showed division activity. Protoplasts derived from stems continued developing and formed microcalli and call. In experiments using stem protoplasts of several varieties, root and stem protoplasts divided in all cases; stem protoplasts of 4 varieties (Riesling, Kemer, Optima, Vidal) could be regenerated to callus. In leaf protoplasts, cell division could be induced only in case of cvs Vidal and Rupestris du Lot, however without formation of callus

The role of RNAi genes in Neurospora crassa post-transcriptional gene silencing

Meiotic silencing was first identified in the bread mold Neurospora crassa (by our group and others) and has since been discovered in worms, mice, and humans. Neurospora is an excellent model organism in that it is inexpensive, has a relatively small number of genes, and a rapid life cycle with two distinct phases. During sexual reproduction, a surveillance system called Meiotic Silencing by Unpaired DNA, or MSUD, inspects all of the chromosomes from both parents for any genes out of place. When an unpaired gene is found, it signals that there might be an invader such as a virus and shuts off every copy of that gene. Significant progress has been made in identifying MSUD components; however, less has been shown about how the components of the MSUD machinery physically interact. In this work, we identified two new components of this process that form a complex with other MSUD components and are important for MSUD

Effect of polyvinylpyrrolidone and activated charcoal on formation of microcallus from grapevine protoplasts (Vitis sp.)

The effect of the addition of polyvinylpyrrolidone (PVP-40) to grapevine protoplast cultures (Vitis sp. cv. Vidal blanc) at different stages of development (day 0, 7 and 14 of cultivation) and the influence of activated charcoal (AC) in several concentrations (0, 0.1, 0.5 and 1.0 %) on protoplast growth were studied. Both additives were investigated using different modified culture media (CPW-13, V/KM, MS-P). The application of 0.5% PVP could not prevent browning of the culture media but reduced it to a low level. Although the effect of PVP on plating efficiency was not clear, the formation of microcalli from grapevine protoplasts was remarkably improved when adding PVP at ''day 0'' or ''day 7'' of cultivation. AC could prevent browning of the media in all concentrations tested but at the same time inhibited plating efficiency. Conversely, formation of microalli occurred only with 0.5 and 1.0% AC, but at very low frequencies. A superior suitability of one of the culture media tested for grapevine protoplasts culture could not been found

Detection of somaclonal variation in grapevine regenerants from protoplasts by RAPD-PCR

Research Not

Regeneration of grapevine (Vitis sp.) protoplasts

Research Not

Development of an in vitro Dual Culture System for Grapevine and Xiphinema index as a Tool for Virus Transmission

Grapevine fanleaf virus (GFLV) is a nepovirus that is transmitted to grapevines by the ectoparasitic nematodeXiphinema index. GFLV causes severe losses in yield and quality in viticulture worldwide. Presently, laborious andtime-consuming field trials or greenhouse tests are necessary for screening putative GFLV resistance in new grapegenotypes developed in breeding programmes. We developed an in vitro dual culture system for grapevines andnematode vectors that requires less time and space than inoculation experiments done in the greenhouse. Virusinfection of in vitro grapevines was investigated using immunocapture-reverse transcriptase-polymerase chainreaction (IC-RT-PCR) analysis. The development of root galls induced by feeding nematodes on in vitro grapevineswas also analysed. Virus infection in grapevines in the dual culture with viruliferous nematodes was detected sixweeks post-inoculation. Root galls were always absent from parasitised in vitro grapevines with detectable virusinfection, whereas they developed on some parasitised, but virus-negative tested grapevines. Therefore, root gallscannot be used as a reliable indicator for parasitism and virus transmission

The use of phosphinothricin resistance as selectable marker for genetic transformation of grapevine

A transformation procedure with the bar gene as a selectable marker was established via Agrobacterium-mediated transformation using strain LBA4404 harbouring the vector pPZP200-bar-gus-intron. Recreation of embryogenic cells from transformation stress in PPT free medium for four weeks improved viability and number of GUS expressing cells. Concentration of 2.5 mg·l-1 PPT yielded highest selection efficiency. Transgenicity of the regenerated grapevine plants was confirmed by histochemical GUS assay and bar specific PCR and RT/PCR. With the described procedure, 20 % of regenerated embryos could be converted into transgenic grapevines.

Lunar and Meteorite Thin Sections for Undergraduate and Graduate Studies

The Johnson Space Center (JSC) has the unique responsibility to curate NASA's extraterrestrial samples from past and future missions. Curation includes documentation, preservation, preparation, and distribution of samples for research, education, and public outreach. Between 1969 and 1972 six Apollo missions brought back 382 kilograms of lunar rocks, core samples, pebbles, sand and dust from the lunar surface. JSC also curates meteorites collected on US expeditions to Antarctica including rocks from Moon, Mars, and many asteroids including Vesta. Studies of rock and soil samples from the Moon and meteorites continue to yield useful information about the early history of the Moon, the Earth, and the inner solar system