Identification and mapping of the Gli-R3 locus on chromosome 1R of rye (Secale cereale L.)

Summary The progenies of two different rye test-crosses were analyzed for secalin proteins by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) using unreduced and reduced aqueous ethanol extracts. Segregation for two high-molecular-weight secalin bands (Glu-R1 or Sec3), one -secalin band (Gli-R1 or Sec-1), two 40K -secalin bands (Gli-R1 or Sec1) and two -type secalin bands (new locus) were studied. One recombinant between - and -secalins was found in one test-cross. The new locus, designated Gli-R3 or Sec-4, was mapped between Glu-R1 and Gli-R1, more displaced towards Gli-R1. In test-cross 1 recombination between Glu-R1 and Gli-R3 was 33.80±3.22%, and between Gli-R3 and Gli-R1, 12.04±2.21%. In the other test-cross the map distances were relatively similar but smaller, likely due to less recombination within two different species of Secale. Genes coding for 40K -secalins at Gli-R1 were likely proximal to the centromere with respect to genes coding for -secalins at the same complex locus.     

Linkage relationships of esterase loci in rye (Secale cereale L.)

Summary Genetic analysis of esterase polymorphism in rye inbred lines with isoelectric focusing in polyacrylamide flat gels yielded evidence for the existence of at least ten esterase loci, Est 1–Est 10. The loci can be attributed to four different linkage groups (Est 1/ Est 2/Est 3/Est 5/Est 6/Est 7), (Est 4), (Est 8/Est 9), and (Est 10). Loci Est 5/Est 6/Est 7 and Est 8/Est 9, respectively, are tightly linked with a maximum recombination frequency of 0.2% and can therefore be regarded as compound loci which possibly originated in tandem duplications.     

Molecular analysis of mitochondrial DNA from rye (Secale cereale L.)

Summary Molecular characterization of mitochondrial (mt) DNA of rye (Secale cereale L.), free of significant amounts of contaminating chloroplast (cp) DNA, was initiated using the open-pollinated cultivar Halo as a source of mtDNA. Based on the compilation of data from restriction patterns, the molecular size of the mtDNA was estimated to be 410 Kb and its buoyant density was determined as 1.705 g/ml. Southern hybridization, using labelled cp genes (P700 and ribulosebiphosphate-carboxylase large subunit), indicated the presence of cpDNA-homologous regions on putative mtDNA fragments. Mt DNAs of inbred lines with fertile and cytoplasmic male sterile (CMS) Pampa cytoplasm were also analysed. Whereas the restriction patterns of mtDNAs of Halors and the fertile line turned out to be identical, Pampa mtDNA showed a unique restriction pattern, indicating (as in most other CMS systems) the involvement of mtDNA rearrangements in the expression of male sterility in rye. All 3 mtDNAs investigated contain regions homologous to the plasmid S1 of the CMS-S cytoplasm of Maize (Zea mays), as indicated by hybridization experiments. In Pampa cytoplasm the S-homologous sequence is located within a rearranged region of mtDNA.     

Linkage mapping of mutant loci in rye (Secale cereale L.)

Eight mutant loci determining the traits waxy plant (w and wa1), brown culm (cb), multiple pistils (mp), weak plant with reduced plant height (np), monoculm growth habit (mc), compactum growth habit (ct3) and anthocyaninless (an) were mapped on rye chromosomes 4R (w, np), 6R (cb, mc) and 7R (mp, wa1, ct3, an). For five mutants (w, wa1, cb, mp, np) molecular and biochemical markers were applied, whereas for mc, ct3 and an a classical linkage analysis was performed. Furthermore, it could be demonstrated that homoeologous relationships exist between most of the mapped rye loci and comparable mutants in wheat and barley. It was confirmed not only that genes controlling fundamental aspects of plant biology are highly conserved across the Triticeae species but so also were many mutant loci. Received: 19 June 2000 / Accepted: 18 October 2000     

Phosphorylation of pollen proteins in relation to self-incompatibility in rye (Secale cereale L.)

The gametophytic two-locus self-incompatibility (SI) system in rye was investigated in view of a possible involvement of protein phosphorylation and Ca²⁺ as constituents of a signal transduction mechanism. Phosphorylation kinetics in pollen grains was found to be significantly different after in vitro treatment of pollen with either cross or self stigma proteins, with a pronounced phosphorylation activity in self-treated pollen grains. Loss of SI in self-compatible (SC) mutants was associated with a significantly decreased basic phosphorylation activity in untreated pollen grains as compared to SI genotypes. Separation of phosphorylated pollen proteins by SDS-PAGE reveals four major proteins in the MW range of 43–82 kDa which were differently phosphorylated in SI vs SC genotypes as well as in cross vs self-treated pollen grains. Application of different protein kinase inhibitors and the Ca²⁺ antagonists verapamil and La³⁺ to isolated stigmas resulted in an inhibition of the SI response in in vitro self-pollination. The role of protein kinases and Ca²⁺ as constituents of a putative SI-specific signal transduction mechanism is discussed.     

B-chromosomes in inbred lines of rye (Secale cereale L.)

B-chromosomes from an experimental population of the Japanese JNK strain of rye, isogenic for its Bs, have been backcrossed into twelve different inbred lines. The experiment provides a way to study the effects of the Bs against a range of homozygous A-chromosome backgrounds. This publication deals with vigour and fertility: it shows that the rye Bs fit a parasitic model, and that they interact in their effects with the A-chromosome background genotype.     

B-chromosomes in inbred lines of rye (Secale cereale L.)

B chromosomes from an experimental population of the Japanese JNK strain of rye, isogenic for its Bs, have been backcrossed into twelve different inbred lines. The experiment is a way of studying the effects of the Bs against a range of different homozygous A chromosome backgrounds. This publication deals with pairing effects of both the As and the Bs, and their interactions, and with pollen mitosis. At meiosis there is a genotypic component to B effects, and they do not appear to act solely through a physical disturbance within the nucleus. In pollen the Bs are always present in more than 50% of the grains regardless of their pairing behaviour during meiosis; this result fits with a parasitic model of the activity of rye Bs.     

Studies on genetic changes in rye samples (Secale cereale L.) maintained in a seed bank

The aim of this study was to identify genetic changes in rye seeds induced by natural ageing during long-term storage and consecutive regeneration cycles under gene bank conditions. Genomic DNA from four rye samples varying in their initial viability after one and three cycles of reproduction was analyzed by AFLP (amplified fragment length polymorphism) fingerprinting. Seven EcoRI/MseI primer combinations defined 663 fragments, and seven PstI/MseI primer combinations defined 551 fragments. The variation in the frequency of the seventy-four EcoRI/MseI bands was statistically significant between samples. These changes could be attributed to genetic changes occurring during storage and regeneration. However, the PstI/MseI fragments appeared to be uninfluenced by seed ageing, regeneration and propagation. A combined Principle Coordinate Analysis revealed differences between samples with different initial viability. We showed that materials with low initial viability differ in their response from highly viable ones, and that the changes exhibited in the former case are preserved through regeneration cycles.     

Chromosomal location of esterase,peroxidase and phosphoglucomutase isozyme structural genes in cultivated rye (Secale cereale L.)

Summary Isoelectric focusing of esterase (EST), peroxidase (PRX), and phosphoglucomutase (PGM) isozymes in Chinese Spring wheat, Imperial rye and several Chinese Spring/Imperial and Holdfast/King II addition, translocation and substitution lines revealed the chromosomal location of nine Est loci previously described and of one Prx and Pgm locus. Loci Est1, Est2, Est3, Est5, Est6 and Est7 were found on chromosome arm 5RL, Est8 and Est9 on chromosome 6R in Imperial rye, and the Est10 locus on chromosome arm 4RL in Imperial rye and King II rye. A discrepancy was found between the chromosomal location of the Prx locus in Imperial where chromosome 2R was responsible for the expression of the peroxidase enzyme, and King II with chromosome 1R carrying the Prx gene. As a possible explanation, the occurrence of translocation events during the production of wheat/rye aneuploid lines is discussed. The rye Pgm locus could be associated with chromosome 4RS in Imperial and King II rye. Except for the location of Est loci on chromosome 5RL, the results reported in this paper lend further evidence for the assumed homoeology relationships between the chromosomes of Triticinae and for the conservation of gene synteny groups during the evolution of the Triticeae tribe.     

Heterochromatin and silver banding of rye (Secale cereale,Gramineae) chromosomes

Air-dried chromosomes of rye when stained with aqueous silver nitrate show differential banding patterns. In addition to staining the NOR sites, the silver nitrate stains all regions of constitutive heterochromatin, as identified by Giemsa C-banding, as well as a number of small interstitial regions. However, the heterochromatin on the B chromosome is not stained by the silver method. This is proposed as a rapid and reliable banding method.     

Linkage and cytogenetic maps of genes controlling endosperm storage proteins and isozymes in rye (Secale cereale L.)

Summary An F₁ plant fromSecale cereale ssp.ancestrale xtelocentric substitution lines3R of the cultivated rye Petkus spring was used as female in a cross with the inbred line Riodeva (I28), which has the standard chromosome arrangement. Single plants from this backcross progeny were analyzed for chromosome constitution, storage protein, and isozymic patterns. The seed protein loci were identified asSec-1a andSec-1b loci controlling 40-K-secalins and-secalins, respectively. These loci are located on the short arm of chromosome1R. TheSec-3 locus controlling high-molecular-weight secalins is located on the long arm of chromosome1R. A further seed protein locus,Pr-3 (55-K protein), was located on the short arm of chromosome1R. A linkage was found between the6Pgd-2 isozyme locus controlling 6-phosphogluconate dehydrogenase isozymes located on the long arm of chromosome1R and the four seed protein loci. The results favor the gene order:6Pgd-2 ...Sec-3 ... [centromere] ...Pr-3 ...Sec-1b ...Sec-1a. Other linkages detected werePer-3a andPer-3b (0.33±0.33 cM),Est-8 andEst-12 (0.33±0.33 cM), andGot-3 and centromere (20.57±2.42 cM). The proxidase (Per), glutamate oxaloacetate transaminase (Got), and esterase (Est) loci were located on chromosome arms2RS,3RL, and6RL, respectively. The distances and the maps obtained are compared with data available in the literature.     

Cold-hardening results in increased activity of enzymes involved in carbon metabolism in leaves of winter rye (Secale cereale L.)

Light- and CO₂-saturated photosynthesis of nonhardened rye (Secale cereale L. cv. Musketeer) was reduced from 18.10 to 7.17 mol O₂·m^–2·s^–1 when leaves were transferred from 20 to 5°C for 30 min. Following cold-hardening at 5°C for ten weeks, photosynthesis recovered to 15.05 mol O₂·m^–2·s^–1,comparable to the nonhardened rate at 20°C. Recovery of photosynthesis was associated with increases in the total activity and activation of enzymes of the photosynthetic carbon-reduction cycle and of sucrose synthesis. The total hexose-phosphate pool increase by 30% and 120% for nonhardened and cold-hardened leaves respectively when measured at 5°C. The large increase in esterified phosphate in coldhardened leaves occurred without a limitation in inorganic phosphate supply. In contrast, the much smaller increase in esterified phosphate in nonhardened leaves was associated with an inhibition of ribulose-1,5-bisphosphate carboxylase/oxygenase and sucrose-phosphate synthase activation. It is suggested that the large increases in hexose phosphates in cold-hardened leaves compensates for the higher substrate threshold concentrations needed for enzyme activation at low temperatures. High substrate concentrations could also compensate for the kinetic limitations imposed by product inhibition from the accumulation of sucrose at 5°C. Nonhardened leaves appear to be unable to compensate in this fashion due to an inadequate supply of inorganic phosphate.Abbreviations DHAP dihydroxyacetone phosphate - Fru6P fructose-6-phosphate - Fru 1,6BP fructose-1,6-bisphosphate - Fru1,6BPase fructose-1,6-bisphosphatase - Glc6P glucose-6-phosphate - PGA 3-phosphoglycerate - PPFD photosynthetic photon flux density - CH cold-hardened rye grown at 5°C - NH nonhardened rye grown at 24°C - Rubisco ribulose-1,5-bisphosphate carboxylase/oxygenase - RuBP ribulose-1,5-bisphosphate - SPS sucrose-phosphate synthase - UDPGlc uridine 5-diphosphoglucose This work was supported by operating grants from the Swedish Natural Sciences Research Council to G.Ö. and P.G.     

Detection of quantitative trait loci on chromosome 5R of rye (Secale cereale L.)

 Progenies of an F₂ mapping population were analyzed for quantitative traits to detect QTLs by using marker information from F₂ plants for chromosome 5R. The mapping population was segregating for the major dwarfing gene Ddw1 and the gene Hp1 for hairy peduncle. The only QTL determining plant height was located between HP1 and Ddw1 on the distal part of chromosome 5RL. At the same position a QTL for peduncle length was found, and this trait was closely related to plant height (r=0.895). Since Hp1 and Ddw1 are dominant marker loci, no dominance effect could be estimated. The QTLs for spike length and the number of florets were located near the centromere on 5RL. These two traits were correlated with r=0.824 and showed partial dominance, but these traits were not correlated to plant height and peduncle length. Homoeologous relationships between the QTLs mapped for the first time in rye and those mapped in other Triticeae members are discussed. Received: 8 June 1998 / Accepted: 8 October 1998     

Acclimation of potassium influx in rye (Secale cereale) to low root temperatures

The influx of K⁺(⁸⁶Rb⁺) into intact roots of rye (Secale cereale L. cv. Rheidal) exposed to a differential temperature (DT) between the root (8° C) and shoot (20° C) is initially reduced compared with warm-grown (WG) controls with both shoot and root maintained at 20° C. Over a period of 3 d, however, K⁺-influx rates into DT plants are restored to levels similar to or greater than those of the WG controls, the absolute rates of K⁺ influx being strongly dependent upon the shoot/root ratio. Acclimation in DT plants results in a reduction of K⁺ influx into the apical (0–2 cm) region of the seminal root which is associated with a compensatory increase in K⁺ influx into the more mature, basal regions of the root. Values of V _max and apparent K _m for K⁺ influx into DT plants were similar to those for WG plants at assay temperatures of 8° C and 20° C except for an increase in the apparent K _m at 8° C. The influx of K⁺ from solutions containing 0.6 mol·m^-3 K⁺ into both WG and DT plants was found to be linearly related to assay temperature over the range 2–27° C, and the temperature sensitivity of K⁺ influx to be dependent upon shoot/root ratio. At high shoot/root ratios, the ratio of K⁺ influx at 20° C:K⁺ influx at 8° C for WG plants approached a minimum value of 1.9 whereas that for DT plants approached unity indicating that K⁺ influx into DT plants has a large temperature-insensitive component. Additionally, when plants were grown in solutions of low potassium concentration, K⁺ influx into DT plants was consistently greater than that into WG plants, in spite of having a greater root potassium concentration ([K⁺]int). This result indicates some change in the regulation of K⁺ influx by [K⁺]int in plants exposed to low root temperatures. We suggest that K⁺ influx into rye seedlings exposed to low root temperatures is regulated by the increased demand placed on the root system by a proportionally larger shoot and that the acclimation of K⁺ influx to low temperatures may be the result of an increased hydraulic conductivity of the root system.Abbreviations DT differential temperature pretreatment - [K⁺]int root potassium concentration - [K⁺]ext potassium concentration of nutrient medium - WG warm-grown pretreatment     

Biochemical evidence of a translocation between 6 RL/7 RL chromosome arms in rye (Secale cereale L.). A genetic map of 6R chromosome

Summary The segregation of different isozymic loci was investigated in backcrosses and F₂s in rye. The leucin aminopeptidase-1 (Lap-1), Aconitase-1 (Aco-1), Esterase-6 (Est-6), Esterase-8 (Est-8), and Endopeptidase-1 (Ep-1) loci were linked. The Aco-1, Est-6, and Est-8 loci have been previously located on the 6RL chromosome arm. The Lap-1 locus has been located on the 6RS chromosome arm. The results favor the gene order: Lap-1... (centromere)... Aco-1... Est-8... Est-6... Ep-1. The isoelectric focusing separations of aqueous extracts from mature embryo tissue of wheat-rye addition and substitution lines involving the chromosomes of cereal rye Secale cereale L. confirmed the gene location of locus Ep-1 on the 6RL chromosome arm. Screening of wheat-rye addition lines involving the chromosomes of Secale montanum revealed that Ep-1 locus is not located on chromosome 6R of S. montanum. These results are the first biochemical evidence of the translocation between chromosome arms 6RL/7RL in the evolution of S. cereale from S. montanum.     

RFLP-based mapping of three mutant loci in rye (Secale cereale L.) and their relation to homoeologous loci within the Gramineae

 Three mutant loci of rye determining absence of ligules (al), waxless plant (wa1) and waxy endosperm (Wx) characters were mapped in a single F₂ population, comprising 84 individual plants. The three loci could be clearly tagged in relation to 7 (al on chromosome 2R), 4 (wa1 on chromosome 7R) or 6 (Wx on chromosome 4R) RFLP markers. The mapping data are compared with existing data for homoeologous regions containing equivalent mutants of wheat, barley, rice and maize. It is shown that the loci analysed are highly conserved across the cereal species, including rye. Received: 14 March 1997 / Accepted: 21 March 1997     

A new type of cytoplasmic male sterility in rye (Secale cereale L.): analysis of mitochondrial DNA

Summary Mitochondrial (mt) DNA of a new type of rye cytoplasm (Gülzow, G) that induces cytoplasmic male sterility (CMS) was analyzed and compared with rye mtDNAs of different origins MtDNA of the G type was easily distinguishable from mtDNA of another CMS source, Pampa (P) type, and from mtDNA of fertile lines with respect to restriction fragment patterns and hybridization with mitochondrial genes. The results of the molecular analyses indicate a close, but not identical relationship between the mtDNA of the G type cytoplasm and that of cv Pluto.     

Genetic mapping of isozyme loci in Secale cereale L.

Summary The genetics and linkage relationships of several isozymatic and morphological markers have been investigated in different cultivars of rye (Secale cereale L.). The inheritance and the variability among cultivars of three new isozymatic zones are described: GOT2 and LAP, each of them under the control of a two-allele single locus, namely Got2 and Lap, respectively; and 6PGD1 controlled by two loci, 6Pgd1a and 6Pgd1b, which have alleles in common. Four linkage groups have been found: Acp2-Acp3, Got3-Mdh2-Lper4, Mdh1-6Pgd2-Pgi2, and Pgm-Eper2-[Eper1-Eper3]. The assignment of these four groups to the chromosomes 7R, 3R, 1R, and 4R is discussed.