Analysis of glutamate oxaloacetate transaminase (GOT) isozyme variants in diploid tuberous Solanum; inheritance and linkage relationships to ds1 (desynapsis), y (tuber flesh colour), cr (crumpled) and yc (yellow cotyledon)

Abstract

Employing polyacrylamide gradient-gel electrophoresis, the genetic control of leaf glutamate oxaloacetate transaminase (GOT) isozyme variants and their linkage to dsl (desynapsis), y (tuber flesh colour), cr (crumpled) and yc (yellow cotyledon) were studied in diploid tuberous Solanum species hybrids .Leaf GOT isozymes proved to be dimeric and under the control of two independently segregating loci (Got-1 and Got-2) with two (Is, 1t) and three (2s, 2j, 2") alleles respectively . The 2" allele was concluded to encode a 2f allozyme subunit capable of forming heterodimeric but no homodimeric active molecules . As expected with Got-1 and Got-2 isozymes being localized in different cellular compartments, no intergenic heterodimer formation was observed .In contrast to earlier studies, a gradual rather than discrete transition between the tuber flesh colour classes white and yellow was observed in segregating progenies . Adopting a standardized classification method, however, monogenic recessive inheritance of white tuber flesh was confirmed .Got-1, dsl and cr were found to represent a single linkage group . Among the presently studied marker loci no further linkages were detected . As to linkage analysis, the difficulties imposed by gametophytic incompatibility in nearly all diploid potato species and by the frequent occurrence of recessive (sub)lethal genes are discussed .

Comparative Analysis of Regions with Distorted Segregation in Three Diploid Populations of Potato

“…Both the presence of loci with sublethal as well as meiotic mutant alleles were also reportedly linked to regions with distorted segregation on chromosomes 10 and 8, respectively ( Jacobs et al 1995 ). These correspond to the recessive crcr “crumpled” morphological mutation [stunted plant with contorted stems and crumpled leaves that died a few weeks after germination ( Jongedijk et al 1990 )] and the ds1ds1 desynaptic meiotic mutant (affecting the development of normal gametes). The cross, described by Jacobs et al (1995) , with a mainly S. tuberosum Groups Tuberosum and Phureja genetic background, allowed the occurrence of nonviable recessive homozygotes for sublethal loci identical by descent, thus producing distorted segregation by zygotic selection.…”

Identifying Lychee Cultivars by Isozyme Analysis

“…For SOD, 5 mg α− naphthol dissolved in 2 ml acetone were added just before staining to a 50 ml solution of 0.1 M phosphate buffer (pH 7.0) containing 50 mg N,N -dimethyl-p-phenelendiamine. For AAT, 1% (w/v) soluble polyvinylpyrrolidone (PVP 40) was added to the staining solution to improve clarity of' the gels (Jongedijk et al, 1990).…”

Transformation of diploid potato genotypes throughAgrobacteriumvectors and expression of T-DNA markers in root clones, regenerated plants and suspension cells

“…vernei, H=S. tuberosum) (Jongedijk & Ramanna 1988), half of the genome of line E is equal to that of C, while the other half is derived from S. vernei and S. tuberosum. Therefore, the recalcitrance to plant regeneration under the present experimental conditions might be ascribed to the S. vernei genome part, or to the genotypic complexity.…”

“…For transformation experiments the following genotypes of Solanum were used: line HH260 (interdihaploid, S. tuberosum, 2n = 2x = 24) (Binding et al 1978); line C (USW5337-3, S. tuberosum x S.phureja, 2n=2x=24), and line E (77.2102-37, 2n=2x= 24) obtained from the cross USW5337-3 (= line C) x VH 342 11 (V = S. vernei; H = S. tuberosum). The lines C and E carry several morphological (desynapsis, crumpled, yellow cotyledon, flower colour, stigma colour, flesh colour), isozyme (GOT!, GOT2, MDHl, PGDH) and resistance markers (resistances against virus Y, Phytophthora and potato leaf rol virus) (Jongedijk & Ramanna 1988, Jongedijk et al 1990). The genotypes were multiplied monthly in vitro as shoot cultures under controlled conditions of 16 h d -1 light (TL type FTD58W33) and 24°C in glass jars on solid MS medium (Murashige & Skoog 1962) supplemented with 2% sucrose and 0·8% agar (Oxoid) (De Vries-Uijtewaal et al 1988).…”

“…Selection of these genotypes was based on several characteristics that are useful for gene mapping and somatic cell genetics. The former two genotypes carry various morphological and isozyme markers (Jongedijk & Ramanna 1989), and the latter genotype exhibits high transformation frequency and high ploidy stability among the hairy root clones and regenerated plants (De Vries-Uijtewaal et al 1988). In addition, results are presented on the expression of the introduced genetic marker characters in various transformed marker lines at the level of root clones, regenerated plants and cell suspension cultures.…”