Aligning a new reference genetic map of Lupinus angustifolius with the genome sequence of the model legume, Lotus japonicus

We have developed a dense reference genetic map of Lupinus angustifolius (2n = 40) based on a set of 106 publicly available recombinant inbred lines derived from a cross between domesticated and wild parental lines. The map comprised 1090 loci in 20 linkage groups and three small clusters, drawing together data from several previous mapping publications plus almost 200 new markers, of which 63 were gene-based markers. A total of 171 mainly gene-based, sequence-tagged site loci served as bridging points for comparing the Lu. angustifolius genome with the genome sequence of the model legume, Lotus japonicus via BLASTn homology searching. Comparative analysis indicated that the genomes of Lu. angustifolius and Lo. japonicus are highly diverged structurally but with significant regions of conserved synteny including the region of the Lu. angustifolius genome containing the pod-shatter resistance gene, lentus. We discuss the potential of synteny analysis for identifying candidate genes for domestication traits in Lu. angustifolius and in improving our understanding of Fabaceae genome evolution.

Identification of quantitative trait loci (QTLs) influencing early vigour, height, flowering date, and seed size and their implications for breeding of narrow-leafed lupin (Lupinus angustifolius L.)

We report the first quantitative trait loci (QTL) mapped in an F8 recombinant inbred line (RIL) population of Lupinus angustifolius. Traits mapped were early vigour, days to flowering, height at maturity, and seed size. Twenty-two QTLs were found, located on 13 linkage groups, with alleles beneficial to the crop contributed by both parents. Early vigour was controlled by 8 QTLs on 7 linkage groups. Time to flowering was controlled by 10 QTLs and the height at maturity was found to be under the control of 4 QTLs. Seed size was linked to 2 QTLs. A region linked to the Ku gene that promotes early flowering by removal of the vernalisation requirement appeared to play a role in all 4 traits. The gene mollis controlling soft-seededness appeared to also be linked to early vigour, and iucundis controlling alkaloid production was linked to seed size. Five pairs of QTLs were found to be involved in epistasis, 2 of these having an effect on early vigour and another 3 influencing the time to opening of the first florets. Variation explained for each trait ranged from 28% for seed size, to 88% for days to flowering. We showed that it was possible to use these data to predict genotypes of superior progeny for these traits under Mediterranean conditions. QTL regions were compared on a second published linkage map and regions of conserved synteny with the model legume Medicago truncatula highlighted.

Construction of a genetic linkage map using MFLP and identification of molecular markers linked to domestication genes in narrow-leafed lupin (Lupinus angustifolius L.)

A mapping population of F(8)derived recombinant inbred lines (RILs) was established from a cross between a domesticated breeding line 83A:476 and a wild type P27255 in narrow-leaf lupin (Lupinus angustifolius L.). The parents together with the 89 RILs were subjected to DNA fingerprinting using microsatellite-anchored fragment length polymorphism (MFLP) to rapidly generate DNA markers to construct a linkage map. Five hundred and twenty two unique markers of which 21% were co-dominant, were generated and mapped. Phenotypic data for the domestication traits: mollis (soft seeds), leucospermus (white flower and seed colour); Lentus (reduced pod-shattering), iucundis (low alkaloid), Ku (early flowering) and moustache pattern on seed coats; were included. Three to 7 molecular markers were identified within 5 cM of each of these domestication genes. The anthracnose resistance gene Lanr1 was also mapped. Linkage groups were constructed using MapManager version QTXb20, resulting in 21 linkage groups consisting of 7 or more markers. The total map length was 1543 cM, with an average distance of 3.4 cM between adjacent markers. This is the first published map for a lupin species. The map can be exploited for marker assisted selection for genetic improvement in lupin breeding programs.

A PCR-based molecular marker applicable for marker-assisted selection for anthracnose disease resistance in lupin breeding

Selection for anthracnose disease resistance is one of the major objectives in lupin breeding programs. The aim of this study was to develop a molecular marker linked to a gene conferring anthracnose resistance in narrow-leafed lupin (Lupinus angustifolius L.), which can be widely used for MAS in lupin breeding. A F(8)derived RIL population from a cross between cultivar Tanjil (resistant to anthracnose) and Unicrop (susceptible) was used for marker development. DNA fingerprinting was conducted on 12 representative plants by combining the AFLP method with primers designed based on conserved sequences of plant disease resistance genes. A co-dominant candidate marker was detected from a DNA fingerprint. The candidate marker was cloned, sequenced, and converted into a sequence-specific, simple PCR based marker. Linkage analysis based on a segregating population consisting of 184 RILs suggested that the marker, designated as AntjM2, is located 2.3 cM away from the R gene conferring anthracnose resistance in L. angustifolius. The marker has now being implemented for MAS in the Australian national lupin breeding program.

Caries Prevalence Measured with QLF after Treatment with Fixed Orthodontic Appliances: Influencing Factors

Caries prevalence on the buccal surfaces of teeth in orthodontic patients was determined with QLF and visual examination immediately after removal of fixed appliances. The number of lesions found by QLF far outnumbered that found by visual examination, but the distribution pattern was similar. 97% of all subjects and on average 30% of the buccal surfaces in a person were affected. On average, in males 40% of surfaces and in females 22% showed white spots (p < 0.01). Caries prevalence was lower (p < 0.01) in incisors and cuspids than in molars and premolars. A positive correlation with caries prevalence was found for the bleeding scores 6 weeks after debonding and lactobacillus counts before debonding. Mutans streptococci counts, age, treatment duration, socioeconomic status and dietary habits showed no correlation with caries prevalence.

Mass-transfer effects on the rate of isomerization of D-glucose into D-fructose, catalyzed by whole-cell immobilized glucose isomerase

The investigated catalyst system consists of immobilized Arthrobacter cells containing the enzyme glucose isomerase, which catalyzes the isomerization of glucose into fructose. The internal structure of the catalyst was determined from electrom microscope photographs of replicas of freeze-etched catalyst. On the basis of the photographs a model for the internal structure of the catalyst was proposed. This structure was subsequently used to describe the reaction including mass-transfer effects. It appeared that under normal operating conditions the external mass-transfer rate does not influence the overall rate of reaction. The effect of internal mass-transfer resistances on the overall reaction rate can well be accounted for by the so-called porous sphere model. The intrinsic kinetics of the isomerization catalyzed by the present catalyst system can be represented by a modified Michaelis-Menten equation for a reversible one-substrate reaction.