13 research outputs found
Production of asymmetric somatic hybrid plants between Cichorium intybus L. and Helianthus annuus L
In order to obtain male-sterile asymmetric somatic
hybrids between chicory (Cichorium intybus L.)
and a sunflower (Helianthus annuus L.) male-sterile cytoplasmic
line, mesophyll chicory protoplasts inactivated
with iodoacetic acid and hypocotyl sunflower protoplasts
irradiated with \u3b3-rays have been fused, using PEG and
applying two different procedures. Thirty three plants
were regenerated from putative hybrid calli. A cytological
analysis of their root-tip cells indicated that most of
them had 18 chromosomes, the same number as chicory.
Through Southern hybridisation on total DNA using the
maize mitochondrial specific gene probes Cox I, Cox II
and Cob, three plants were identified as cytoplasmic
asymmetric hybrids, as shown by hybridisation bands
specific for both chicory and sunflower. One of the regenerated
plants produced a novel pattern of hybridisation
that was not detected in either parent. When hybridisation
of total DNA was carried out with an atpA mitochondrial
gene probe the same three cybrids presented
both the fertile chicory fragment and the male-sterile
sunflower fragment. Finally, Southern hybridisation with
an ORF 522 probe, which in sunflower is co-transcribed
with the atpA gene, confirmed the hybrid nature of the
three plants. The morphology of the cybrids resembled
the parental chicory phenotype, and at anthesis their anthers
produced fewer pollen grains which could not germinate
either \u201din vitro\u201d or \u201din situ.\u201d Cybrid plants grown
in the field produced seeds when free-pollination occurre
An efficient and rapid procedure for plantlets regeneration from chicory mesophyll protoplasts
An efficient procedure for plantlet regeneration from chicory mesophyll protoplasts has been developed in order to perform protoplast fusion experiments. Protoplasts were isolated from a genotype of Italian red chicory (CH 363) and purified by centrifugation in a solution containing 13% (w/v) sucrose to collect uniform protoplasts in size. After 2 days culture at a density of 2x104 protoplasts ml-1 of liquid medium, protoplasts were cultured following three different procedures: in liquid medium, stratified in semi-solid medium, and embedded in Ca-alginate droplets. Four different media were used and culture procedures were evaluated recording the protoplast viability, protoplast division frequency and plating efficiency for each experiment. The embedding of protoplasts in Ca-alginate droplets enhanced both division frequency and plating efficiency for chicory mesophyll cells. Furthermore, this procedure shortened the cycle of plant regeneration from protoplasts, which could be completed in
eight weeks
Production of asymmetric somatic hybrid plants between Cichorium intybus L. and Helianthus annuus L.
Transfer of anthracnose resistance and pod coiling traits from Medicago arborea to M. sativa by sexual reproduction
Five asymmetric hybrid plants were obtained between Medicago sativa (2n = 4x = 32) and Medicago arborea (2n = 4x = 32) through sexual reproduction and the use of a cytoplasmically male sterile M. sativa genotype. Over 2,000 pollinations were made to obtain these hybrids. Amplified fragment length polymorphism (AFLP) analysis showed that in the most studied hybrid (WA2273), 4% of the bands unique to the M. arborea parent were present, versus 72% for the unique M. sativa bands. This suggests that only a single M. arborea chromosome or chromosome parts has been transferred. WA2273 had 7% of AFLP bands which were not present in either parent, which is suggestive of chromosome rearrangements as would be expected if only chromosome parts or a single part had been transferred from M. arborea. Phenotypic evidence for hybridity was obtained for pod coiling (1.4 coils in WA2273 versus three coils in the M. sativa parent and its self and testcross populations, and one coil in M. arborea), and Colletotrichum trifolii race 2 resistance (transferred from the resistant M. arborea parent, as the M. sativa parent and the self populations were highly susceptible). The hybrids were self sterile, but were female fertile to a high level when crossed with 4x, but not 2x, M. sativa, indicating they were at or near 4x. Both the pod coiling trait and anthracnose resistance segregated in the progeny of testcrosses between WA2273 and M. sativa. The work demonstrates that agronomically useful traits can be introgressed into M. sativa from M. arborea by use of male sterile M. sativa and sexual reproduction
Plant regeneration from proroplasts of alfalfa (Medicago sativa) via somatic embryogenesis Regeneração de plantas a partir de protoplastos de alfafa (Medicago sativa) via embriogênese somática
Alfalfa is one of the most frequently studied species from the production of tissue culture-derived embryos point of view. In this study, five alfalfa cultivars were analyzed with reference to their ability to regenerate plants from protoplast cultures via somatic embryogenesis. Plant regeneration from leaf-derived protoplasts isolated from the cultivar Rangelander was achieved using a protocol defined for alfalfa cell suspension-derived embryogenesis. Because of its high efficiency, this procedure is recommended for protoplast electroporation-mediated genetic transformation of alfalfa.<br>A alfafa é uma das espécies mais freqüentemente estudadas do ponto de vista da produção de embriões somáticos derivados da cultura de tecidos. Neste trabalho, cinco cultivares de alfafa foram analisados com referência à capacidade de regenerar plantas a partir de culturas de protoplastos via embriogênese somática. Regeneração de plantas a partir de protoplastos isolados de folhas da cultivar Rangelander foi obtida usando-se um protocolo definido para embriogênese somática derivada de suspensões celulares de alfafa. Em função da sua alta eficiência, recomenda-se o uso deste procedimento para transformação genética de alfafa mediada por eletroporação de protoplastos