Origin of leaf rust adult plant resistance gene Rph20 in barley

Rph20 is the only reported, simply inherited gene conferring moderate to high levels of adult plant resistance (APR) to leaf rust (Puccinia hordei Otth) in barley (Hordeum vulgare L.). Key parental genotypes were examined to determine the origin of Rph20 in two-rowed barley. The Dutch cultivar 'Vada' (released in the 1950s) and parents, 'Hordeum laevigatum' and 'Gull' ('Gold'), along with the related cultivar 'Emir' (a derivative of 'Delta'), were assessed for APR to P. hordei in a disease screening nursery. The marker bPb-0837-PCR, co-located with Rph20 on the short arm of chromosome 5H (5HS), was used to screen genotypes for the resistance allele, Rph20.ai. Results from phenotypic assessment and DNA analysis confirmed that Rph20 originated from the landrace 'H. laevigatum' (i.e., Hordeum vulgare subsp. vulgare). Tracing back this gene through the pedigrees of two-rowed barley cultivars, indicated that Rph20 has contributed APR to P. hordei for more than 60 years. Although there have been no reports of an Rph20-virulent pathotype, the search for alternative sources of APR should continue to avoid widespread reliance upon a single resistance factor.

Symptom development proceeds at different rates in susceptible and partially resistant cereal seedlings infected with Fusarium pseudograminearum

Variation in the reaction of cereal cultivars to crown rot caused by Fusarium spp., in particular Fusarium pseudograminearum, was identified over 50 yrs ago, however the parameters and pathways of infection by F. pseudograminearum remain poorly understood. Seedlings of wheat, barley and oat genotypes that differ in susceptibility to crown rot were inoculated with a mixture of F. pseudograminearum isolates. Seedlings were harvested from 7 to 42 days after inoculation and expanded plant parts were rated for severity of visible disease symptoms. Individual leaf sheaths were placed onto nutrient media and fungal colonies emerging from the leaf sheathes were counted to estimate the degree of fungal spread within the host tissue. Significant differences in both the timing and the severity of disease symptoms were observed in the leaf sheath tissues of different host genotypes. Across all genotypes and plant parts examined, the development of visible symptoms closely correlated with the spread of the fungus into that tissue. The degree of infection of the coleoptile and sub-crown internode varied between genotypes, but was unrelated to the putative resistance of the host. In contrast leaf sheath tissues of the susceptible barley cv. Tallon and bread wheat cv. Puseas scored higher disease ratings and consistently showed faster, earlier spread of the fungus into younger tissues than infections of the oat cv. Cleanleaf or the wheat lines 2-49 and CPI 133814. While initial infections usually spread upwards from near the base of the first leaf sheath, the pathogen did not appear to invade younger leaf sheaths only from the base, but rather spread laterally across from older leaf sheaths into younger, subtended leaf sheaths, particularly as disease progressed. Early in the infection of each leaf sheath, disease symptoms in the partially resistant genotypes were less severe than in susceptible genotypes, however as infected leaf sheaths aged, differences between genotypes lessened as disease symptoms approached maximum values. Hence, while visual scoring of disease symptoms on leaf sheaths is a reliable comparative measure of the degree of fungal infection, differences between genotypes in the development of disease symptoms are more reliably assessed using the most recently expanded leaf sheaths.

Biodiversity and Phylogeny of Planktic Cyanobacteria in Temperate Freshwater Lakes

Currently, the classification used for cyanobacteria is based mainly on morphology. In many cases the classification is known to be incongruent with the phylogeny of cyanobacteria. The evaluation of this classification is complicated by the fact that numerous strains are only described morphologically and have not been isolated. Moreover, the phenotype of many cyanobacterial strains alters during prolonged laboratory cultivation. In this thesis, cyanobacterial strains were isolated from lakes (mainly Lake Tuusulanjärvi) and both morphology and phylogeny of the isolates were investigated. The cyanobacterial community composition in Lake Tuusulanjärvi was followed for two years in order to relate the success of cyanobacterial phenotypes and genotypes to environmental conditions. In addition, molecular biological methods were compared with traditional microscopic enumeration and their ability and usefulness in describing the cyanobacterial diversity was evaluated. The Anabaena, Aphanizomenon, and Trichormus strains were genetically heterogeneous and polyphyletic. The phylogenetic relationships of the heterocytous cyanobacteria were not congruent with their classification. In contrast to heterocytous cyanobacteria, the phylogenetic relationships of the Snowella and Woronichinia strains, which had not been studied before this thesis, reflected the morphology of strains and followed their current classification. The Snowella strains formed a monophyletic cluster, which was most closely related to the Woronichinia strain. In addition, a new cluster of thin, filamentous cyanobacterial strains identified as Limnothrix redekei was revealed. This cluster was not closely related to any other known cyanobacteria. The cyanobacterial community composition in Lake Tuusulanjärvi was studied with molecular methods [denaturant gradient gel electrophoresis (DGGE) and cloning of the 16S rRNA gene], through enumerations of cyanobacteria under microscope, and by strain isolations. Microcystis, Anabaena/Aphanizomenon, and Synechococcus were the major groups in the cyanobacterial community in Lake Tuusulanjärvi during the two-year monitoring period. These groups showed seasonal succession, and their success was related to different environmental conditions. The major groups of the cyanobacterial community were detected by all used methods. However, cloning gave higher estimates than microscopy for the proportions of heterocytous cyanobacteria and Synechococcus. The differences were probably caused by the high 16S rRNA gene copy numbers in heterotrophic cyanobacteria and by problems in the identification and detection of unicellular cyanobacteria.

Associations of gene polymorphisms and nutrition with calcium homeostasis and bone mineral density : Studies on skeletal nutrigenetics

Heredity explains a major part of the variation in calcium homeostasis and bone strength, and the susceptibility to osteoporosis is polygenetically regulated. Bone phenotype results from the interplay between lifestyle and genes, and several nutritional factors modulate bone health throughout life. Thus, nutrigenetics examining the genetic variation in nutrient intake and homeostatic control is an important research area in the etiology of osteoporosis. Despite continuing progress in the search for candidate genes for osteoporosis, the results thus far have been inconclusive. The main objective of this thesis was to investigate the associations of lactase, vitamin D receptor (VDR), calcium sensing receptor (CaSR) and parathyroid hormone (PTH) gene polymorphisms and lifestyle factors and their interactions with bone health in Finns at varying stages of the skeletal life span. Markers of calcium homeostasis and bone remodelling were measured from blood and urine samples. Bone strength was measured at peripheral and central bone sites. Lifestyle factors were assessed with questionnaires and interviews. Genetic lactase non-persistence (the C/C-13910 genotype) was associated with lower consumption of milk from childhood, predisposing females in particular to inadequate calcium intake. Consumption of low-lactose milk and milk products was shown to decrease the risk for inadequate calcium intake. In young adulthood, bone loss was more common in males than in females. Males with the lactase C/C-13910 genotype may be more susceptible to bone loss than males with the other lactase genotypes, although calcium intake predicts changes in bone mass more than the lactase genotype. The BsmI and FokI polymorphisms of the VDR gene were associated with bone mass in growing adolescents, but the associations weakened with age. In young adults, the A986S polymorphism of the calcium sensing receptor gene was associated with serum ionized calcium concentrations, and the BstBI polymorphism of the parathyroid gene was related to bone strength. The FokI polymorphism and sodium intake showed an interaction effect on urinary calcium excretion. A novel gene-gene interaction between the VDR FokI and PTH BstBI gene polymorphisms was found in the regulation of PTH secretion and urinary calcium excretion. Further research should be carried out with more number of Finns at varying stages of the skeletal life span and more detailed measurements of bone strength. Research should concern mechanisms by which genetic variants affect calcium homeostasis and bone strength, and the role of diet-gene and gene-gene interactions in the pathogenesis of osteoporosis.

Tuotantotekniikan ja säilytysajan vaikutus kasvihuonekurkkujen ja -tomaattien aistittavaan laatuun.

Finland has moved from growing vegetables by natural light to year-round greenhouse production using artificial lighting. Determination of sensory effects on greenhouse-grown vegetables is important as sensory evaluation provides information which chemical methods can not. It can tell us about the quality of samples which affects the consumers' behaviour. There are different opinions on how the quality of vegetables should be determined. The consumers are dissatisfied with the quality of vegetables and fruits, although the variety of products is larger than ever. The aim of this study was to find out how artificial lighting contributes to the sensory quality of greenhouse tomatoes and cucumbers compared to traditional natural lighting, and how storage affects the sensory attributes of the samples. In this study there were two sets of tomatoes and two sets of cucumbers, representing two different harvest seasons. Sensory evaluation involved two steps. The first step was to sort the samples and the second step was to generate a profile using descriptive analysis. Sorting was found to give some approximate information on differences between tomato and cucumber samples. MDS-maps dimensions were presented by age and lighting technique. The reliability of sorting results was quite good. The quality of the natural products was inconsistent. Production technology had more of an effect on cucumber samples than tomato samples. Natural light cucumbers were, for example sweeter and softer than artificial light cucumbers. Age had an especially large effect on cucumber appearance characteristics. There were less differences between tomato samples than cucumber samples. Production technology had less of an effect on tomato samples than age, e.g. hardness decreased during storage. In this study, it was found that artificial lighting has little effect on the sensory quality of Finnish greenhouse tomatoes compared with tomatoes grown under natural light.

A dynamic programming model for optimising feeding and slaughter decisions regarding fattening pigs

Costs of purchasing new piglets and of feeding them until slaughter are the main variable expenditures in pig fattening. They both depend on slaughter intensity, the nature of feeding patterns and the technological constraints of pig fattening, such as genotype. Therefore, it is of interest to examine the effect of production technology and changes in input and output prices on feeding and slaughter decisions. This study examines the problem by using a dynamic programming model that links genetic characteristics of a pig to feeding decisions and the timing of slaughter and takes into account how these jointly affect the quality-adjusted value of a carcass. The model simulates the growth mechanism of a pig under optional feeding and slaughter patterns and then solves the optimal feeding and slaughter decisions recursively. The state of nature and the genotype of a pig are known in the analysis. The main contribution of this study is the dynamic approach that explicitly takes into account carcass quality while simultaneously optimising feeding and slaughter decisions. The method maximises the internal rate of return to the capacity unit. Hence, the results can have vital impact on competitiveness of pig production, which is known to be quite capital-intensive. The results suggest that producer can significantly benefit from improvements in the pig's genotype, because they improve efficiency of pig production. The annual benefits from obtaining pigs of improved genotype can be more than €20 per capacity unit. The annual net benefits of animal breeding to pig farms can also be considerable. Animals of improved genotype can reach optimal slaughter maturity quicker and produce leaner meat than animals of poor genotype. In order to fully utilise the benefits of animal breeding, the producer must adjust feeding and slaughter patterns on the basis of genotype. The results suggest that the producer can benefit from flexible feeding technology. The flexible feeding technology segregates pigs into groups according to their weight, carcass leanness, genotype and sex and thereafter optimises feeding and slaughter decisions separately for these groups. Typically, such a technology provides incentives to feed piglets with protein-rich feed such that the genetic potential to produce leaner meat is fully utilised. When the pig approaches slaughter maturity, the share of protein-rich feed in the diet gradually decreases and the amount of energy-rich feed increases. Generally, the optimal slaughter weight is within the weight range that pays the highest price per kilogram of pig meat. The optimal feeding pattern and the optimal timing of slaughter depend on price ratios. Particularly, an increase in the price of pig meat provides incentives to increase the growth rates up to the pig's biological maximum by increasing the amount of energy in the feed. Price changes and changes in slaughter premium can also have large income effects. Key words: barley, carcass composition, dynamic programming, feeding, genotypes, lean, pig fattening, precision agriculture, productivity, slaughter weight, soybeans

More fertile florets and grains per spike can be achieved at higher temperature in wheat lines with high spike biomass and sugar content at booting

An understanding of processes regulating wheat floret and grain number at higher temperatures is required to better exploit genetic variation. In this study we tested the hypothesis that at higher temperatures, a reduction in floret fertility is associated with a decrease in soluble sugars and this response is exacerbated in genotypes low in water soluble carbohydrates (WSC). Four recombinant inbred lines contrasting for stem WSC were grown at 20/10 degrees C and 11 h photoperiod until terminal spikelet, and then continued in a factorial combination of 20/10 degrees C or 28/14 degrees C with 11 h or 16 h photoperiod until anthesis. Across environments, High WSC lines had more grains per spike associated with more florets per spike. The number of fertile florets was associated with spike biomass at booting and, by extension, with glucose amount, both higher in High WSC lines. At booting, High WSC lines had higher fixed C-13 and higher levels of expression of genes involved in photosynthesis and sucrose transport and lower in sucrose degradation compared with Low WSC lines. At higher temperature, the intrinsic rate of floret development rate before booting was slower in High WSC lines. Grain set declined with the intrinsic rate of floret development before booting, with an advantage for High WSC lines at 28/14 degrees C and 16 h. Genotypic and environmental action on floret fertility and grain set was summarised in a model.

A physiological framework to explain genetic and environmental regulation of tillering in sorghum

Tillering determines the plant size of sorghum (Sorghum bicolor) and an understanding of its regulation is important to match genotypes to prevalent growing conditions in target production environments. The aim of this study was to determine the physiological and environmental regulation of variability in tillering among sorghum genotypes, and to develop a framework for this regulation. * Diverse sorghum genotypes were grown in three experiments with contrasting temperature, radiation and plant density to create variation in tillering. Data on phenology, tillering, and leaf and plant size were collected. A carbohydrate supply/demand (S/D) index that incorporated environmental and genotypic parameters was developed to represent the effects of assimilate availability on tillering. Genotypic differences in tillering not explained by this index were defined as propensity to tiller (PTT) and probably represented hormonal effects. * Genotypic variation in tillering was associated with differences in leaf width, stem diameter and PTT. The S/D index captured most of the environmental effects on tillering and PTT most of the genotypic effects. * A framework that captures genetic and environmental regulation of tillering through assimilate availability and PTT was developed, and provides a basis for the development of a model that connects genetic control of tillering to its phenotypic consequences.

Resistance to Fusarium oxysporum f. sp fragariae and Predicted Breeding Values in Strawberry

Fusarium wilt of strawberry, incited by Fusarium oxysporum f. sp. fragariae (Fof), is a major disease of the cultivated strawberry (Fragaria xananassa) worldwide. An increase in disease outbreaks of the pathogen in Western Australia and Queensland plus the search for alternative disease management strategies place emphasis on the development of resistant cultivars. In response, a partial incomplete diallel cross involving four parents was performed for use in glasshouse resistance screenings. The resulting progeny were evaluated for their susceptibility to Fof. Best-performing progeny and suitability of progenies as parents were determined using data from disease severity ratings and analyzed using a linear mixed model incorporating a pedigree to produce best linear unbiased predictions of breeding values. Variation in disease response, ranging from highly susceptible to resistant, indicates a quantitative effect. The estimate of the narrow-sense heritability was 0.49 +/- 0.04 (SE), suggesting the population should be responsive to phenotypic recurrent selection. Several progeny genotypes have predicted breeding values higher than any of the parents. Knowledge of Fof resistance derived from this study can help select best parents for future crosses for the development of new strawberry cultivars with Fof resistance.

Plot size matters: interference from intergenotypic competition in plant phenotyping studies

Genetic and physiological studies often comprise genotypes diverse in vigour, size and flowering time. This can make the phenotyping of complex traits challenging, particularly those associated with canopy development, biomass and yield, as the environment of one genotype can be influenced by a neighbouring genotype. Limited seed and space may encourage field assessment in single, spaced rows or in small, unbordered plots, whereas the convenience of a controlled environment or greenhouse makes pot studies tempting. However, the relevance of such growing conditions to commercial field-grown crops is unclear and often doubtful. Competition for water, light and nutrients necessary for canopy growth will be variable where immediate neighbours are genetically different, particularly under stress conditions, where competition for resources and influence on productivity is greatest. Small hills and rod-rows maximise the potential for intergenotypic competition that is not relevant to a crop’s performance in monocultures. Response to resource availability will typically vary among diverse genotypes to alter genotype ranking and reduce heritability for all growth-related traits, with the possible exception of harvest index. Validation of pot experiments to performance in canopies in the field is essential, whereas the planting of multirow plots and the simple exclusion of plot borders at harvest will increase experimental precision and confidence in genotype performance in target environments.

Quantitative effects of in-line operations on Campylobacter and Escherichia coli through two Australian broiler processing plants

Campylobacter is an important food borne pathogen, mainly associated with poultry. A lack of through-chain quantitative Campylobacter data has been highlighted within quantitative risk assessments. The aim of this study was to quantitatively and qualitatively measure Campylobacter and Escherichia coli concentration on chicken carcasses through poultry slaughter. Chickens (n = 240) were sampled from each of four flocks along the processing chain, before scald, after scald, before chill, after chill, after packaging and from individual caeca. The overall prevalence of Campylobacter after packaging was 83% with a median concentration of 0.8 log10 CFU/mL. The processing points of scalding and chilling had significant mean reductions of both Campylobacter (1.8 and 2.9 log10 CFU/carcase) and E. coli (1.3 and 2.5 log10 CFU/carcase). The concentration of E. coli and Campylobacter was significantly correlated throughout processing indicating that E. coli may be a useful indicator organism for reductions in Campylobacter concentration. The carriage of species varied between flocks, with two flocks dominated by Campylobacter coli and two flocks dominated by Campylobacter jejuni. Current processing practices can lead to significant reductions in the concentration of Campylobacter on carcasses. Further understanding of the variable effect of processing on Campylobacter and the survival of specific genotypes may enable more targeted interventions to reduce the concentration of this poultry associated pathogen.

Large-scale characterization of drought pattern: a continent-wide modelling approach applied to the Australian wheatbelt – spatial and temporal trends

* Plant response to drought is complex, so that traits adapted to a specific drought type can confer disadvantage in another drought type. Understanding which type(s) of drought to target is of prime importance for crop improvement. * Modelling was used to quantify seasonal drought patterns for a check variety across the Australian wheatbelt, using 123 yr of weather data for representative locations and managements. Two other genotypes were used to simulate the impact of maturity on drought pattern. * Four major environment types summarized the variability in drought pattern over time and space. Severe stress beginning before flowering was common (44% of occurrences), with (24%) or without (20%) relief during grain filling. High variability occurred from year to year, differing with geographical region. With few exceptions, all four environment types occurred in most seasons, for each location, management system and genotype. * Applications of such environment characterization are proposed to assist breeding and research to focus on germplasm, traits and genes of interest for target environments. The method was applied at a continental scale to highly variable environments and could be extended to other crops, to other drought-prone regions around the world, and to quantify potential changes in drought patterns under future climates.

Genetic diversity of the Australian National Mango Genebank

Assessment of genetic diversity is an essential component in germplasm characterisation and utilisation. In this study the genetic diversity of mango was determined among 254 Mangifera indica L. accessions and related Mangifera species originating from 12 diverse geographic areas using eleven known simple sequence repeat (SSR) markers from mango. A total of 133 alleles were detected, ranging from eight (LMMA12) to 16 (MIAC-5) alleles per locus with a mean value of 12.36 and an average polymorphism information content (PLC) of 0.72. The mean number of alleles (8.45) was highest in the South East Asian accessions (Indonesia/Malesia) and lowest in the accessions from the Philippines (2.55). Diversity analysis divided the accessions into four major nodes broadly representing their geographical origins. The genetic diversity of 'Kensington Pride' was confirmed as being very low and no parents for this cultivar were identified. No association could be established between SSR markers analysed and embryony. Ten synonymous accessions were identified with matching genetic identity with at least one other accession at all SSR loci examined. Twenty-two unique genotypes were identified for 50 trees previously assigned different accession names. The remaining accessions were genetically distinct from each other. This increased understanding of genetic diversity in the Australian National Mango Genebank will assist breeders to better select parents with the potential to contribute desired genes to the progeny and thus more rapidly deliver improved cultivars to industry to meet consumer demand. Crown Copyright (C) 2012 Published by Elsevier B.V. All rights reserved.

QTL analysis in multiple sorghum populations facilitates the dissection of the genetic and physiological control of tillering

Tillering in sorghum can be associated with either the carbon supply–demand (S/D) balance of the plant or an intrinsic propensity to tiller (PTT). Knowledge of the genetic control of tillering could assist breeders in selecting germplasm with tillering characteristics appropriate for their target environments. The aims of this study were to identify QTL for tillering and component traits associated with the S/D balance or PTT, to develop a framework model for the genetic control of tillering in sorghum. Four mapping populations were grown in a number of experiments in south east Queensland, Australia. The QTL analysis suggested that the contribution of traits associated with either the S/D balance or PTT to the genotypic differences in tillering differed among populations. Thirty-four tillering QTL were identified across the populations, of which 15 were novel to this study. Additionally, half of the tillering QTL co-located with QTL for component traits. A comparison of tillering QTL and candidate gene locations identified numerous coincident QTL and gene locations across populations, including the identification of common non-synonymous SNPs in the parental genotypes of two mapping populations in a sorghum homologue of MAX1, a gene involved in the control of tiller bud outgrowth through the production of strigolactones. Combined with a framework for crop physiological processes that underpin genotypic differences in tillering, the co-location of QTL for tillering and component traits and candidate genes allowed the development of a framework QTL model for the genetic control of tillering in sorghum.

The effect of lycopene on the PI3K/Akt signalling pathway in prostate cancer

Prostate cancer is common in men with very high mortality which is one of leading causes of cancer-related deaths in men. The main treatment approaches for metastasized prostate cancer are androgen deprivation and chemotherapeutic agents. Although there are initial responses to castration, the resistance to the treatment will eventually occur, leading to castration-resistant prostate cancer. The common chemotherapeutic agents for the treatment of prostate cancer are docetaxel and taxane but outcomes of using these drugs have not been satisfactory. Therefore, it is necessary to find better treatment approaches for prostate cancer and to search for compounds that are effective in prostate cancer prevention. Lycopene extracted from tomato and other fruits or plants such as Gac, watermelon, pink grapefruit, pink guava, red carrot and papaya has been shown to be effective on prostate cancer prevention and treatment. The advantage of the application of lycopene for its anti-prostate cancer activity is that lycopene can reach much higher concentration in prostate tissue than other tissues. In this review, the effect of lycopene on PI3K/Akt pathway is summarised, which could be one of major mechanisms for anti-cancer activity of lycopene.