Eighteen isozyme systems were surveyed in the peach [Prunus persica (L.) Batsch.] plant introduction collection. Seven systems were polymorphic. Three previously unreported isocitrate dehydrogenase (IDH; EC 188.8.131.52), three malate dehydrogenase (MDH; EC 184.108.40.206) and two shikimate dehydrogenase (SDH; EC 220.127.116.11) banding patterns were detected in the clones. Isocitrate dehydrogenase was dimeric in structure, with two alleles present at a single locus. Malate dehydrogenase was dimeric in structure, with three alleles present at the fast locus, while a second locus was monomorphic. Shikimate dehydrogenase was monomeric, with one allele present in most clones, while PI 113452, PI 113650, and PI 117679 were heterozygous for a slow SDH allele. Electrophoretic evidence suggests PI 113452, PI 113650, and PI 117679 are peach × almond (P. dulcis Webb) hybrids, since they were heterozygous for alleles previously reported only in almond.
Bruce D. Mowrey, Dennis J. Werner, and David H. Byrne
Shiow Y. Wang, Hong J. Jiao, and Miklos Faust
The activity of glucose-6-phosphate dehydrogenase (G6PDH), 6-phosphate gluconate dehydrogenase (6PGDH), isocitrate dehydrogenase (ICDH), pyruvate kinase (PK), and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) were studied in apple (Malus domestics Borkh.) buds during dormancy and thidiazuron-induced budbreak. When buds were dormant, the activity of the glycolytic enzymes GAPDH and PK and the tricarboxylic acid (TCA) cycle enzyme ICDH was low compared to that in nondormant buds. The activity of these enzymes increased during budbreak, peaked when buds were in the green tip stage just before the start of rapid expansion (at 8 days after thidiazuron treatment), and declined thereafter. The activity of pentose-phosphate cycle enzymes G6PDH and 6PGDH was higher in dormant buds than in nondormant buds. 6PGDH was about twice as high as G6PDH. During budbreak and resumption of growth, G6PDH and 6PGDH activity decreased.
Johanne C. Cousineau and Danielle J. Donnelly
Abbreviations: IDH, isocitrate dehydrogenase; MDH, malate dehydrogenase; PGI, phosphoglucoisomerase; PGM, phosphoglucomutase; TPI, triose phosphate isomerase. Partial financial support from the Natural Sciences and Engineering Research Council of
Brandon R. Smith and Lailiang Cheng
MgSO 4 , 5 m m MnCl 2 , 1 m m DTT, 0.5 m m NADP, 2 units of NADP-isocitrate dehydrogenase (IDH), and 75 μL of enzyme extract. The reaction was initiated by adding 10 m m cis -aconitate. NAD-malic enzyme was assayed by measuring the amount of
Larry S. Kennedy and Paul G. Thompson
The enzymes alcohol dehydrogenase, diaphorase, esterase, glutamate dehydrogenase, glucosephosphate isomerase, isocitrate dehydrogenase, malate dehydrogenase, malic enzyme, 6-phosphogluconate dehydrogenase, phosphoglucomutase, shikimate dehydrogenase, and xanthine dehydrogenase were analyzed by starch gel electrophoresis of leaf tissue from nine sweetpotato [Ipomoea batatas (L.) Lam.] cultivars. Bands of most enzymes were well-defined. Polymorphisms were found in nine enzymes, and cultivars were identified by comparing polymorphisms.
Chemda Degani, Ruth El-Batsri, and Shmuel Gazit
Forty-one (Mangifera indica L.) cultivars were characterized electrophoretically using the isozyme systems aconitase, isocitrate dehydrogenase, leucine aminopeptidase, phosphoglucose isomerase, phosphoglucomutase, and triosephosphate isomerase. The outcross origin of some of the mango cultivars was supported by the isozymic banding patterns. Reported parentage of some other cultivars was not consistent with their isozymic banding patterns.
J.C. Cousineau, A.K. Anderson, H.A. Daubeny, and D.J. Donnelly
Isoenzyme staining of horizontal starch gels was used to characterize 23 cultivars and three advanced selections of red raspberry (Rubus idaeus L.). The genotypes were separable using the enzymes malate dehydrogenase, phosphoglucoisomerase, phosphoglucomutase, and triose phosphate isomerase. In addition, staining for isocitrate dehydrogenase and shikimate dehydrogenase revealed polymorphisms in some cultivars. By combining these results with those obtained for 78 previously tested cultivars, 75 of the 104 (72%) genotypes tested were uniquely characterized using the six isoenzymes.
Ramon Dolcet-Sanjuan, Elisabet Claveria, and Agustin Huerta
A new and simple protocol for androgenesis in bell pepper is described. The initial medium, a modification of Nitsch and Nitsch's H medium, consisted of a two-phase system of semi-solid and liquid medium and contained maltose as carbon source. The total number of embryos formed was greater with maltose at 40 g·L-1, but embryos developed better at 10 to 20 g·L-1. Depending on the genotype, the number of embryos and plants recovered ranged from 3 to 750 and 0.25 to 8, respectively, per 100 flowers. Further increases in the number of embryos (up to 3561 per 100 flowers) and plants (up to 23 per 100 flowers) could be attained by flushing cultures with air enriched with CO2 at 900 μL·L-1. The ploidy level and the microspore origin of the recovered plants were determined by flow cytometry and zymograms for isocitrate dehydrogenase. Nearly 65% of the acclimated plants had undergone spontaneous doubling of the chromosome number, as confirmed by flow cytometry of leaf nuclei. Isocitrate dehydrogenase zymograms demonstrated that plants originated from microspores and that the two parental alleles were equally represented among the haploid and dihaploid plants.
Ramon Dolcet-Sanjuan and Elisabet Claveria
Anthers from more than 17000 flowers of 19 bell pepper Capsicum annuum L. hybrids (provided by `Semillas Fitó S.A.') were cultured in a double layer modified H medium (Nitsch and Nitsch, 1969) supplemented with 0.5 % activated charcoal and 0.26 % Gelrite in the solid phase. Significant differences between genotypes were observed on embryogenesis (472.3 to 9.7 embryos / 100 flowers) and number of plants rescued (4.0 to 0.3 plants / 100 flowers). Trying out maltose, malt extract, and sucrose. as carbohydrates, at 20, 40, 60 or 80 g/l, gave significantly better results for maltose (20 or 40 g/l). In addition, maintaining the anther cultures in an atmosphere enriched with 600 ppm CO2 was beneficial for embryo number, embryo development and number of rescued plants. Isocitrate dehydrogenase zymograms from leaf extracts indicate the microspore origin of the acclimated plants. Flow citometry of nuclei was used to determined an early diploidization of 70 % of the acclimated plants.
James Beaver and Amy Iezzoni
Starch gel electrophoresis was employed to study inheritance and diversity of allozyme loci in a sour cherry (2n=4×=32) germplasm collection. Segregation data was collected for alcohol dehydrogenase (ADH), glucose phosphate isomerase (GPI), isocitrate dehydrogenase (IDH), leucine amino peptidase (LAP), malate dehydrogenase (MDH), peroxidase (PX) (cathodal activity), phosphoglucomutase (PGM), 6-phosphogluconic dehydrogenase (6-PGD), and shikimate dehydrogenase (s k d h).
Data suggest that alleles can be assigned to many of the enzyme systems being studied: ADH, GPI, IDH, LAP, PGM, and 6-PGD. Most loci are diallelic and often exhibit the unbalanced heterozygous condition. MDH, PX, and 6-PGD are highly polymorphic. Progeny segregation data fit disomic inheritance models, indicating that sour cherry is an allotetraploid.