Specific Proteins Maintained in Maize Callus Cultures (original) (raw)
Related papers
Analysis of Genetic Variability in Long-term Callus Cultures and Regenerated Plants of Maize
CYTOLOGIA, 1998
Zea mays ssp. mays cv. Colorado Klein organogenic calli were initiated from 11 days old embryos on basic medium containing 2.25 ƒÊM 2,4-D. The callus originated from one of the embryos was subcultured every month to fresh medium supplemented with 4.5 or 9 ƒÊM 2,4-D, for 84 months. The first chromosomal abnormalities appeared after 17 months of culture: 70% of regenerated plants were normal, 20% aneuploid and the remaining 10% were tetraploid. Thereafter chromosomal aberrations increased. Most (95%) of the plants regenerated after 32 months had one extra chromosome, and meiotic analysis of regenerants showed deficiencies, duplications, inversions, translocations and ring chromosomes. Chromosome number of cells from 60 months old callus ranged from 2n=18 to 2n=23, but 90% of regenerated plants had 2n=21 and the remaining 10% had 2n=20. Plants regenerated from 64 to 84 months old callus were sterile. Also, phenotypic alterations were observed in plants regenerated from 32 months and older calli. Although original maize plants are yellow flint, 75% of R0 ears showed white flint kernels and their progeny exhibited yellow flint, white flint, white dent and white sugary caryopses.
Plant Science, 1986
Friable callus (type 2) was selected from three genotypes (A188, hybrid A188 x B73, and hybrid B73 x A188) of Zea mays L. The three genotypes of type 2 callus doubled in fresh weight after 1 week, and growth was better on N6 than on Murashige-Skoog (MS) medium. Type 2 callus of hybrid B73 x A188 was maintained in culture longer than A188 type 2 callus, and it regenerated higher numbers of plants than the other two genotypes. Type 2 callus of the hybrid B73 × A188 was used to establish cell suspensions. Suspension cells initially grew better on N6 than on MS medium, but after several months of subculture, cells in either N6 or MS medium grew at similar rates. Suspension cells were in mid-log phase by 5-7 days and in stationary phase by about 10 days depending on inoculum density. Growth rate was optimal when cells were transferred at mid-low phase and dry weight of the suspension cells increased at least 10-fold during a 10-day period. Suspension cells from 9-month-old cultures plated on solid medium regenerated plants at an efficiency similar to that of the friable type 2 callus but with more phenotypic abnormalities. Thus, cell suspensions derived from type 2 B73 x A188 callus, in culture for over 1 year, were capable of regenerating plants when 9-months old.
Callus induction and regeneration of elite Indian maize inbreds
AFRICAN JOURNAL OF BIOTECHNOLOGY
Five elite Indian maize inbreds namely; HKI1105, HKI1105, HKI335, CM300 and LM5 were evaluated for callus induction and regeneration. Immature embryos obtained 14 days after pollination were used as explants. Genotype, medium, type of auxin and their concentrations influenced callus induction. N 6 medium supplemented with different concentration of 2,4-D (1, 2 and 3 mg/l) and Dicamba (1, 2 and 3 mg/l) were used for callus induction. N 6 supplemented with 2 mg/l of 2,4-D has shown highest percentage of embryogenic callus induction. Among the five genotypes tested, CM300 gave highest percentage of embryogenic calli. CM300 and LM5 both have shown higher regeneration percentage of 12.22%.
Callus Induction of Some Inbred Maize Varieties
Tissue and cell culture systems are vital to manyareas of maize research and improvement. In the present research two inbred lines i.e. SD7 and SD34 were used to obtian callus induction. The highest values for alive callus were 260 and 180 in SD7 and 34, respectively after six selections, while, the lowest values were 137 and 120 in respect. The overall of alive callus was 190 and 148 and dead callus was 76 and 2.17 for SD7 and 34.The percentage of dead callus was 2% compared with the other variety was 40%.
Plant Cell Reports, 1989
Isozyme analyses were carried out on protein extracts of non-embryogenic and embryogenic callus from Zea mays L., using polyacrylamide gel electrophoresis. We examined the isozyme patterns of glutamate dehydrogenase, peroxidase and acid phosphatase for their utility as biochemical markers of maize embryogenic callus cultures. These isozyme systems were also used to examinepossibleoorrelationsbetween isozymes and different stages of regeneration. The zymograms of peroxidase and glutamate dehydrogenase differed for non-embryegenic and embryogenic callus. Further, some isozymes were correlated with the morphological appearance of the tissue while others seemed to be involved with the duration of the culture period. Using the same enzyme assays on fresh tissue samples we were able to test the three enzymes as cytochemical markers in embryogenic cultures. Glutamate dehydrogenase proved to be most successful to discriminate embryogenic from non-embryogenic cells.
Plant molecular …, 2006
Gene expression patterns were profiled during somatic embryogenesis in a regeneration-proficient maize hybrid line, Hi II, in an effort to identify genes that might be used as developmental markers or targets to optimize regeneration steps for recovering maize plants from tissue culture. Gene expression profiles were generated from embryogenic calli induced to undergo embryo maturation and germination. Over 1,000 genes in the 12,060 element arrays showed significant time variation during somatic embryo development. A substantial number of genes were downregulated during embryo maturation, largely histone and ribosomal protein genes, which may result from a slowdown in cell proliferation and growth during embryo maturation. The expression of these genes dramatically recovered at germination. Other genes up-regulated during embryo maturation included genes encoding hydrolytic enzymes (nucleases, glucosidases and proteases) and a few storage genes (an alpha-zein and caleosin), which are good candidates for developmental marker genes. Germination is accompanied by the up-regulation of a number of stress response and membrane transporter genes, and, as expected, greening is associated with the up-regulation of many genes encoding photosynthetic and chloroplast components. Thus, some, but not all genes typically associated with zygotic embryogenesis are significantly up or down-regulated during somatic embryogenesis in Hi II maize line regeneration. Although many genes varied in expression throughout somatic embryo development in this study, no statistically significant gene expression changes were detected between total embryogenic callus and callus enriched for transition stage somatic embryos.
Type II callus production and plant regeneration in tropical maize genotypes
Plant Cell Reports, 1997
A total of 113 maize inbreds adapted to tropical conditions were evaluated for their tissue culture response. Additionally, four media combinations of 15 or 30 µm dicamba with or without 88 µm AgNO3 were used to study the effect of dicamba and AgNO3 on type II callus production and plant regeneration from 42 of the inbred lines. Inbreds 48, 389 and 1345 of the populations BR 105, BR 112, and Catete, respectively, showed a high capacity for type II callus production and plant regeneration. The production of type II calli increased significantly when the concentration of dicamba was changed from 15 to 30 µm and when AgNO3 was added to the medium. A synergistic effect between 88 µm AgNO3 and 30 µm dicamba (CM-30Ag medium) was observed, leading to additional production of type II callus. Medium CM-30Ag allowed the best tissue culture performance and plant regeneration capacity.
Theoretical and Applied Genetics, 1992
The frequency of initiation of friable, embryogenic callus from immature embryos of the elite maize inbred line B73 was increased dramatically by introgression of chromosomal segments from the inbred line A188 through classical backcross breeding. Less than 0.2% of the immature B73 embryos tested (5 of 3,710) formed embryogenic callus. The breeding scheme consisted of six generations of backcrossing to B73 with selection at each generation for high frequency initiation of embryogenic cultures. BC6 individuals were selfed for four generations to select homozygous lines. The average embryogenic culture initiation frequency increased to 46% (256/561). Nearly all (91%) of the embryos from one BC6 S4 plant formed embryogenic cultures. RFLP analysis was used to determine the locations and effects of the introgressed A188 chromosomal segments. Five segments were retained through at least the fifth backcross generation. The hypothesis that one or more of these five regions contains genes controlling somatic embryogenesis in maize was tested using an F2 population of the cross A188 X Mo17. A set of five DNA markers (three of them linked) explained 82% of the observed phenotypic variance for percentage of immature embryos forming embryognic callus. Four of the five markers were located in or near introgressed A188 chromosome segments. The region marked by probe c595 on the long arm of chromosome 9 was highly associated with several measures of in vitro culture response (percent embryogenic embryos, plants per embryo, and plants per embryogenic embryo). We propose that there is a major gene (or genes) in this region in A188 that promotes embryogenic callus initiation and plant regeneration in B73, Mo17, and probably many other recalcitrant inbred lines of maize.