Claire Doré

Routine transformation of rapid cycling cabbage (Brassica oleracea) : molecular evidence for regeneration of chimeras

Abstract We have developed a transformation procedure using both disarmed and wild-type Agrobacterium tumefaciens strains for a rapid-cycling cabbage genotype ( Brassica oleracea var. capitata ). This method is based on the fact that the wild-type A. tumefaciens strain (82.139) can induce shooty tumors in rapid-cycling cabbage. No special regeneration medium was required and no selection pressure was exerted at any stage of the transformation procedure; the transformants were identified by screening for β-glucuronidase (GUS) activity with a histological assay. Southern analyses ascertained that the GUS-expressing plants contained the T-DNA carried by the disarmed strain but not the T-DNA of the wild-type A. tumefaciens strain. One transgenic plant was obtained for an average of 25 plants inoculated. Southern analysis showed that most of the transgenic plants, under these non-selective conditions, proved to be chimeric. Regeneration was established to be of pluricellular origin. The transgenic plants transmitted their T-DNA inserts to the progeny.

Embryogenesis and plant regeneration of pakchoi (Brassica rapa L. ssp. chinensis) via in vitro isolated microspore culture.

Isolated microspores of various populations of three varieties of the Chinese cabbage pakchoi (Brassica rapa ssp. chinensis) were cultivated in vitro on NLN82 medium (Lichter 1982) and embryos and plantlets obtained with nine cultivars. The best embryo yield per bud was 57.4. A 33°C one day heat treatment was generally necessary to induce embryogenesis. Analysis of ploidy level through flow cytometry for two cultivars indicated that haploids were present.

Interspecific hybridization of Phaseolus vulgaris L. and Phaseolus angustissimus A. Gray using in vitro embryo culture

The introgression of new desirable characters is very necessary in common bean (Phaseolus vulgaris L.)Interspecific hybridization of P. vulgaris L. with P. angustissimus A. Gray, a wild species with narrow leaves, could be successfully achieved for the first time using embryo culture. Sixteen to twenty-three-day old embryos could grow to plantlets when they were cultivated on modified Monniers medium.The leaf shape of the hybrid plants obtained showed intermediary traits between the two parents.A chromosome stock doubling could be achieved for one embryo.

Comparison of gas chromatography–mass spectrometry and electronic tongue analysis for the classification of onions and shallots

Onions and Jersey shallots belong to the same species (Allium cepa L.), but are from two different groups: cepa and aggregatum. The grey shallot belongs to Allium oschaninii O. Fedtsch. Onions and shallots differ in taste but however both contain same sulfur volatile compounds making sensory evaluation difficult. There is a practical need to reliably discriminate onion from shallot. The aim of this study was to evaluate and compare the classification of several cultivars of onions and shallots by the ‘electronic tongue’ and by the chemical analysis of their fresh aroma. The ‘e-tongue’ is an analytical instrument comprising an array of cross-sensitive chemical sensors. The fresh aroma of onion and shallot due to sulfur compounds (thiosulfinates and zwiebelanes) was analysed by GC-MS. Data processing was performed by PCA. The ‘e-tongue’ and GC-MS chemical analysis were able to separate onions from shallots. The grey shallot and the white onion were separated from all samples by the two techniques, a result which fits well with its botanical nature. The differentiation between seed-propagated cultivars (all onions and a few shallots) from the vegetative produced ones (all the classic shallots) was also done. The two methods appeared compatible and sometimes complementary.

In situ gynogenetic haploid plants of chicory (Cichorium intybus L.) after intergeneric hybridization with Cicerbita alpina Walbr.

The possibility of obtaining haploid plants of chicory (Cichorium intybus L.) was investigated through intergeneric hybridization. Chicory plants (industrial chicory and Chioggia) were pollinated with pollen of Lactuca tatarica L. and Cicerbita alpina Walbr. Many achenes contained embryos which were rescued in vitro. Only a few embryos developed into plants which were then acclimatized in soil. Among them, three expressed a chicory phenorype and were haploid

Gamma irradiation of the female gametophyte in cabbage (Brassica oleracea L.)

SummaryWe examined the prospects for using the female gametophyte irradiation technique in cabbage to reduce the number of generations needed for cytoplasm transfer. Three different crosses were used with one nuclear and two cytoplasmic male-sterile lines as female parents. The doses applied ranged from 100 to 700 Gy. Differences between the genotypes were observed only in embryo and plant production with varying dose. Several plants derived from the various experiments exhibited one or two recessive paternal markers and an aneuploid number of chromosomes, which shows an irradiation-induced loss of maternal chromosomes. However, no androgenetic haploid plant was obtained. The aneuploid plants could sometimes be backcrossed, and in one case a shift in the segregation ratio towards the paternal (non-irradiated) phenotype was observed. We concluded that while the female gametophyte irradiation technique could reduce the number of generations necessary for cytoplasm transfer, the damage induced seems too restricted for this technique to be applied in cabbage breeding at present.