1,721,067 research outputs found
ISOZYME VARIATION IN LEAF-CALLUS REGENERATED PLANTS OF SOLANUM-TUBEROSUM
No full textElectrophoretic patterns of isozymes, allowing the direct study of gene products, represent a valid tool in detecting genetic and epigenetic variations both involved in determining somaclonal variation. In the present work, three isozyme systems, glutamate-oxalacetate transaminase (GOT, EC 2.6.1.1), alcohol dehydrogenase (ADH, EC 1.1.1.1), and esterase (EST, EC 3.1.1.1), were analyzed in different organs of callus-regenerated plants of potato and on the tubers of the first vegetative reproduction. As concerns ADH and GOT, the electrophoretic patterns showed the disappearance of one band in may regenerated plants in respect to the parental cultivar. This loss of allele expression can be determined by a stable (ADH) or by an unstable change (GOT) as suggested by the permanence or not of the variation in the tubers. The electrofocusing of esterase revealed the presence of additional bands in respect of parental cultivar. Taking into account that somaclonal variation might arise as the response of the genome to a shock caused by tissue culture, it is suggested that sequence rearrangements represent likely mechanisms respectively involved in the loss or in the appearance of gene expression
Efficiency of transient transformation in tobacco protoplasts is independent of plasmid amount
No full textAn optimized protocol for the
transient transformation of tobacco protoplasts mediated
by polyethylene–glycol (PEG) is here described. As expected, the quantitative
b–glucuronidase (Gus) activity driven by pCaMVGus
was dependent on the amount of plasmid used.
Nevertheless, we demonstrate by an immunodetection
method that transformation efficiency did not depend on
the amount of plasmid used but on the limitation imposed
by cell competence. In fact, we obtained the same
percentage of transformed cells (about 60%) using a wide
range of plasmid concentrations (0.1–10 mg per test).
Finally, we show that, when we used two plasmid types in
a mixture at a concentration ranging from 0.1 to 10 mg for
each, all transformed cells expressed proteins encoded by
both plasmids. Transient expression and co-transformation
experiments are routinely used methods and, probably,
the major results from this work were assumed by
many researchers in this field, but our data experimentally
support this assumption
The sax1 dwarf mutant of Arabidopsis thaliana shows altered sensitivity of growth responses to abscisic acid, auxin, giberellin and ethylene and is partially rescued by exogenous brassinosteroid
No full textGenetic approaches using Arabidopsis thaliana aimed at the identification of mutations affecting events involved in auxin signalling have usually led to the isolation of auxin-resistant mutants. From a selection screen specifically developed to isolate auxin-hypersensitive mutants, one mutant line was selected for its increased sensitivity to auxin (x 2 to 3) for the root elongation response. The genetic analysis of sax1 (hypersensitive to abscisic acid and auxin) indicated that the mutant phenotype segregates as a single recessive Mendelian locus, mapping to the lower arm of chromosome 1. Sax1 seedlings grown in vitro showed a short curled primary root and small, round, dark-green cotyledons. In the greenhouse, adult sax1 plants were characterized by a dwarf phenotype, delayed development and reduced fertility. Further physiological characterization of sax1 seedlings revealed that the most striking trait was a large increase (x 40) in ABA-sensitivity of root elongation and, to a lesser extent, of ABA-induced stomatal closure; in other respects, hypocotyl elongation was resistant to gibberellins and ethylene. These alterations in hormone sensitivity in sax1 plants co-segregated with the dwarf phenotype suggesting that processes involved in cell elongation are modified. Treatment of mutant seedlings with an exogenous brassinosteroid partially rescued a wild-type size, suggesting that brassinosteroid biosynthesis might be affected in sax1 plants. Wild-type sensitivities to ABA, auxin and gibberellins were also restored in sax1 plants by exogenous application of brassinosteroid, illustrating the pivotal importance of the BR-related SAX1 gene
Uso del fattore trascrizionale Mybleu per la produzione di piante transgeniche tolleranti gli stress abiotici
No full textLa presente invenzione riguarda l'uso del gene di riso Osmyb4 e dei suoi omologhi funzionali per l'ottenimento di piante con aumentata tolleranza a stress abiotic
Use of di specific Myb genes for the production of the transgenic plants tolerant to biotic and abiotic stresses
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