Opines in naturally infected grapevine crown gall tumors

Crown gall tumors collected from naturally infected plants of 7 grapevine varieties were analysed for the presence of opines. Eighty-five of the tested 90 samples contained known Agrobacterium vitis-induced opines. Octopine was the most common, it was found in 50 samples. Twentyeight crown galls contained nopaline and 8 were vitopine positive. There was only one tumor that contained two opines, nopaline and vitopine. Five samples were negative for the opines tested. The presence of A. vitis was confirmed in most of these tumors by PCR analysis. The opine assay may provide a simple diagnostic protocol to distinguish healthy callus tissues from crown galls as well as for the indirect identification of Agrobacterium infection.

The intermediate-mass star-forming region Lynds 1340. An optical view

We have performed an optical spectroscopic and photometric search for young stellar objects associated with the molecular cloud Lynds 1340, and examined the structure of the cloud by constructing an extinction map, based on SDSS data. The new extinction map suggests a shallow, strongly fragmented cloud, having a mass of some 3700~Msun. Longslit spectroscopic observations of the brightest stars over the area of L1340 revealed that the most massive star associated with L1340 is a B4 type, about 5 solar mass star. The new spectroscopic and photometric data of the intermediate mass members led to a revised distance of 825 (+110 /-80) pc, and revealed seven members of the young stellar population with M > 2 solar masses. Our search for H alpha emission line stars, conducted with the Wide Field Grism Spectrograph 2 on the 2.2-meter telescope of the University of Hawaii and covering a 30 arcmin x 40 arcmin area, resulted in the detection of 75 candidate low-mass pre-main sequence stars, 58 of which are new. We constructed spectral energy distributions of our target stars, based on SDSS, 2MASS, Spitzer, and WISE photometric data, derived their spectral types, extinctions, and luminosities from BVRIJ fluxes, estimated masses by means of pre-main sequence evolutionary models, and examined the disk properties utilizing the 2-24 micron interval of the spectral energy distribution. We measured the equivalent width of the H alpha lines and derived accretion rates. The optically selected sample of pre-main sequence stars has a median effective temperature of 3970 K, stellar mass 0.7 Msun, and accretion rate of 7.6 10^{-9} Msun/yr.Comment: 47 pages, 15 figures, 10 tables; accepted for publication in ApJ, typos correcte

Detection of Agrobacterium vitis by polymerase chain reaction in grapevine bleeding sap after isolation on a semiselective medium

DNA samples prepared from 15 Agrobacterium vitis and one A. tumefaciens strains were tested in polymerase chain reaction with 4 primer pairs. The pTiC58 virC specific primers did not detect any A. vitis, while the polygalacturonase specific primers resulted in positive reactions with all grapevine strains. Octopine and nopaline strains could be distinguished from vitopine strains by virE2 specific primers. Like for other bacterial species Triton X-100 with sodium-azide strongly increased the sensitivity of detection of A. vitis. Fourty-six colonies were isolated on a tartrate medium from grapevine bleeding sap collected from galled  and  symptomless Vitis  vinifera  cv. Cabernet Sauvignon and Riesling plants. Fourteen of them were identified by PCR as A. vitis, 11 of which proved to be pathogenic. Analysis of bleeding sap for A. vitis may become a useful diagnostic method for selection of healthy plants.

Studies on the inheritance of resistance to crown gall disease of grapevine

Nearly 1800 seedlings of 27 hybrid families were screened for resistance to A. tumefaciens strain AT-1 belonging to biotype 3. The tested families included 12 crosses of sensitive and of resistant phenotypes, and 15 self-pollinated families both of sensitive and of resistant parents. Resistance originated from V. amurensis. The segregation ratio corresponded to 1 : 1 among the crosses and was 3 : 1 (resistant to sensitive) among the selfings of resistant parents. All seedlings from selved susceptible parents formed tumors. According to our results, a Mendelian dominant inheritance can be proposed for resistance to A. tumefaciens strain AT-1.Untersuchungen zur Vererbung der Mauke-Resistenz bei der RebeAnnähernd 1800 Genotypen aus 27 Kreuzungsfamilien wurden auf ihre Anfälligkeit gegen den Stamm AT-1 des Biotyps 3 von Agrobacterium tumefaciens geprüft. Die untersuchten Kreuzungsfamilien umfaßten 12 Kreuzungskombinationen resistenter und anfälliger Phänotypen und 15 Selbstungen resistenter und anfälliger Eltern. Die Quelle der Mauke-Resistenz ist Vitis amurensis. Das Aufspaltungsverhältnis zwischen resistenten und anfälligen Sämlingen beträgt bei Fremdbefruchtung 1 : 1 und bei Selbstung der resistenten Eltern 3 : 1; bei Selbstung der anfälligen Eltern bildete jeder Sämling Tumoren aus. Aufgrund der Ergebnisse kann eine dominante Vererbung der Resistenz gegen A. tumefaciens AT-1 angenommen werden

Elimination of mites from the buds of dormant grapevine cuttings by hot water treatment

The suitability of hot water treatment was tested for eliminating overwintering mites from dormant grapevine buds. Treatment at 52 °C for 60 min completely eliminated mite infestation, but did not or only slightly influenced the viability of grapevine buds. In greenhouse experiments we demonstrated that treated plants frequently showed a better growth, most probably due to the elimination of mite infestation. This additional application of hot water treatment provides a simple, environment-friendly and economical method to prevent spreading of grapevine mites

Rapid purification of grapevine RNA by a simple electrophoretic method

Research Not

Crown gall resistance in East-Asian Vitis species and in their V. vinifera hybrids

Crown gall resistance of ca. 50 interspecific hybrids obtained from Vitis vinifera mainly with V. amurensis was tested. Resistance to Agrobacterium tumefaciens strain AT-1 was expressed via 4 generations. Further 11 strains representing the 3 biotypes of the pathogen did not cause tumors on the hybrids A6/1 and A5/43. A6/1 has already been certificated as variety Kunbarát. According to the results achieved, resistance breeding could provide an effective means to prevent crown gall disease of grapevine.Resistenz gegen Mauke bei ostasiatischen Vitis-Arten und ihren Kreuzungen mit V. viniferaCa. 50 interspezifische Kreuzungen von Vitis vinifera überwiegend mit V. amurensis wurden auf ihre Resistenz gegen Mauke untersucht. Die Resistenz gegen Agrobacterium tumefaciens, Stamm AT-1, manifestierte sich über 4 Generationen. Die Kreuzungen A6/1 und A5/43 waren gegen weitere 11 Stämme von A. tumefaciens resistent. Die resistente Kreuzung A6/1 ist unter dem Sortennamen Kunbarát bereits staatlich anerkannt. Aufgrund der vorliegenden Ergebnisse dürfte die Resistenzzüchtung eine wirksame Methode zum Schutz der Weinrebe gegen die Mauke sein

Erratum

Thidiazuron-induced regeneration and genetic transformation of grapevine rootstock varietiesVitis 42 (3), 133- 136 (2003

Thidiazuron-induced regeneration and genetic transformation of grapevine rootstock varieties

In vitro regeneration from cell to plant, a technique considered to be an important precondition of gene transfer, was attempted in 12 grapevine rootstocks starting with anthers of the plants as inocula. Embryogenic callus was induced in solid Murashige-Skoog medium supplemented with 2,4-dichlorophenoxyacetic acid (2,4-D) and thidiazuron (TDZ). Five of the tested rootstock cultivars (Börner, Richter 110, SO 4, St. George and Teleki 5 C) yielded embryogenic callus lines that regenerated entire plants. From these cultures Richter 110 and St. George varieties produced transgenic plants following Agrobacterium-mediated transformation with an nptII/gusA gene construct using a simple, but effective cocultivation protocol. The putative transgenic lines expressed the gusA gene. The T-DNA transfer and integration was confirmed by PCR analysis.

Identification of Young Stellar Object candidates in the GaiaGaia DR2 x AllWISE catalogue with machine learning methods

The second $Gaia$ Data Release (DR2) contains astrometric and photometric data for more than 1.6 billion objects with mean $Gaia$ $G$ magnitude $<$20.7, including many Young Stellar Objects (YSOs) in different evolutionary stages. In order to explore the YSO population of the Milky Way, we combined the $Gaia$ DR2 database with WISE and Planck measurements and made an all-sky probabilistic catalogue of YSOs using machine learning techniques, such as Support Vector Machines, Random Forests, or Neural Networks. Our input catalogue contains 103 million objects from the DR2xAllWISE cross-match table. We classified each object into four main classes: YSOs, extragalactic objects, main-sequence stars and evolved stars. At a 90% probability threshold we identified 1,129,295 YSO candidates. To demonstrate the quality and potential of our YSO catalogue, here we present two applications of it. (1) We explore the 3D structure of the Orion A star forming complex and show that the spatial distribution of the YSOs classified by our procedure is in agreement with recent results from the literature. (2) We use our catalogue to classify published $Gaia$ Science Alerts. As $Gaia$ measures the sources at multiple epochs, it can efficiently discover transient events, including sudden brightness changes of YSOs caused by dynamic processes of their circumstellar disk. However, in many cases the physical nature of the published alert sources are not known. A cross-check with our new catalogue shows that about 30% more of the published $Gaia$ alerts can most likely be attributed to YSO activity. The catalogue can be also useful to identify YSOs among future $Gaia$ alerts.Comment: 19 pages, 12 figures, 3 table