Bevan Buirchell

Development and implementation of a sequence-specific PCR marker linked to a gene conferring resistance to anthracnose disease in narrow-leafed lupin (Lupinus angustifolius L.)

Anthracnose caused by Colletotrichum gloeosporioides is the most serious disease of lupins (Lupinus spp). A cross was made between cultivars Tanjil (resistant) and Unicrop (susceptible) in narrow-leafed lupin (L. angustifolius). Analysis of disease reaction data on the F2 population and on the resultant F7 recombinant inbred lines suggested that Tanjil contained a single dominant gene (Lanr1) conferring resistance to anthracnose. The parents and the representative F2 plants were used to generate molecular markers liked to the Lanr1 gene using the MFLP technique. A co-dominant MFLP polymorphism linked to the Lanr1 gene was identified as a candidate marker. The bands were isolated, re-amplified by PCR, cloned and sequenced. The MFLP polymorphism was converted into a co-dominant, sequence-specific, simple PCR-based marker. Linkage analysis by the computer program MAPMAKER indicated that the marker was 3.5 centiMorgans (cM) from the gene Lanr1. This marker is currently being implemented for marker assisted selection in the Australian National Lupin Breeding Program.

Metabolism of estradiol-17β in human endometrium during the menstrual cycle

Abstract [ 3 H]-estradiol-17β was incubated with endometrium obtained at different times during the menstrual cycle. The percentage of the [ 3 H]-estradiol-17β metabolized was measured. Secretory endometrium metabolizes estradiol-17β at a greater rate than proliferative endometrium. Proliferative endometrium metabolizes estradiol-17β to estrone while secretory endometrium, under the influence of progesterone, metabolizes estradiol-17β to water soluble metabolites and a small quantity of estrone. The production and excretion of water soluble metabolites by the secretory endometrium is rapid. Endometrium showing cystic hyperplasia or adenocarcinoma metabolizes estradiol-17β at the same rate as proliferative endometrium.

Plant Virology and Next Generation Sequencing: Experiences with a Potyvirus

Next generation sequencing is quickly emerging as the go-to tool for plant virologists when sequencing whole virus genomes, and undertaking plant metagenomic studies for new virus discoveries. This study aims to compare the genomic and biological properties of Bean yellow mosaic virus (BYMV) (genus Potyvirus), isolates from Lupinus angustifolius plants with black pod syndrome (BPS), systemic necrosis or non-necrotic symptoms, and from two other plant species. When one Clover yellow vein virus (ClYVV) (genus Potyvirus) and 22 BYMV isolates were sequenced on the Illumina HiSeq2000, one new ClYVV and 23 new BYMV sequences were obtained. When the 23 new BYMV genomes were compared with 17 other BYMV genomes available on Genbank, phylogenetic analysis provided strong support for existence of nine phylogenetic groupings. Biological studies involving seven isolates of BYMV and one of ClYVV gave no symptoms or reactions that could be used to distinguish BYMV isolates from L. angustifolius plants with black pod syndrome from other isolates. Here, we propose that the current system of nomenclature based on biological properties be replaced by numbered groups (I–IX). This is because use of whole genomes revealed that the previous phylogenetic grouping system based on partial sequences of virus genomes and original isolation hosts was unsustainable. This study also demonstrated that, where next generation sequencing is used to obtain complete plant virus genomes, consideration needs to be given to issues regarding sample preparation, adequate levels of coverage across a genome and methods of assembly. It also provided important lessons that will be helpful to other plant virologists using next generation sequencing in the future.

The growth of Lupinus species on alkaline soils

Lupinus angustifolius L. grows poorly on alkaline soils, particularly those that are fine-textured. This poor growth has been attributed to high concentrations of bicarbonate, high clay content and/or iron deficiency. In field studies, we examined the growth of 13 lupin genotypes reliant on N2 fixation, or receiving NH4N03, at four sites with various combinations of soil pH and texture. Plants grown on an alkaline clay and an alkaline sand showed iron chlorosis at early stages, and had a slower shoot growth than those grown on an acid loam or an acid sand. Species varied greatly in the severity of iron chlorosis and also in growth and seed yield, with L. angustifolius, L. luteus and L. albus more affected than L. pilosus, L. atlanticus and L. cosentinii. Rankings of growth and seed yield of the lupin genotypes on the alkaline clay correlated well with the rankings on the alkaline sand soil. Plants which had severe iron chlorosis in alkaline clay also had severe chlorosis in alkaline sands. However, correlation between the severity of iron chlorosis and early shoot growth was poor. The results suggest that high pH and/or high bicarbonate are more likely than soil texture to be the primary factors restricting the growth of commercial lupins.

Variation in the growth of lupin species and genotypes on alkaline soil

Commercial lupins grow poorly on alkaline and neutral fine-textured soils. Genotypic variation exists among lupins. The present study compared the growth of 13 lupin genotypes, including introduced cultivars and wild types, in an alkaline loamy soil and an acid loamy soil.

Ecogeography of the Old World lupins. 1. Ecotypic variation in yellow lupin (Lupinus luteus L.)

Agricultural crops and their wild progenitors are excellent candidates for ecophysiologal research because germplasm collections are often extensive and well described, and in its dissemination the crop may explore new habitats. The advent of high-resolution climate models has greatly improved our capacity to characterise plant habitats, and study species’ adaptive responses. The yellow lupin (Lupinus luteus) is ideal because it evolved as a Mediterranean winter-annual in relatively high-rainfall coastal regions, but was domesticated as a summer crop in temperate central Europe. Currently the crop is being developed for Mediterranean south-western Australia, raising an interesting ecophysiological problem: is it more appropriate to concentrate on wild material from Mediterranean habitats, which are likely to be more similar to the target environments, or on European germplasm domesticated for temperate summer cropping? Lupinus luteus collection sites across the natural and domesticated distribution range were characterised by calculating site-specific bioclimatic variables and habitat types defined using multivariate analysis. Germplasm was evaluated in 2 field trials measuring a range of characters describing plant growth, phenology, architecture, and productivity. The earliest phenology and highest vigour and productivity were recorded in domesticated material from central Europe, characterised by short but unstressful growing seasons with reliable rainfall, long day-lengths, and rapidly rising vegetative-phase temperatures levelling out after flowering. Mediterranean habitats were classified by altitude, climate, and growing-season length. Early, productive germplasm came from warmer/low elevation sites with inconsistent rainfall and stronger terminal drought. Germplasm from low temperature/high elevation sites with high, relatively frequent rainfall had late phenology and low growth rates, early vigour, seed yield, and harvest index. Distinct habitats within the distribution range of L. luteus have selected for ecotypes with different phenologies and growth rates, which strongly influence plant architecture, fecundity and yield. It is suggested that variable responses to vernalisation and differences in seed size are important in determining these traits. European germplasm has many of the terminal drought-avoiding characteristics required in a productive Mediterranean ideotype, but may lack drought tolerance, which is likely to be under stronger selection pressure in more stressful Mediterranean habitats.

A model for incorporating novel alleles from the primary gene pool into elite crop breeding programs while reselecting major genes for domestication or adaptation

Cost, time, linkage drag, and genetic drift work against the incorporation of potentially valuable alleles from exotic or non-adapted germplasm into elite crop plants, particularly for quantitative traits. We present a model, motivated by narrow-leafed lupin (Lupinus angustifolius), for efficient incorporation of new alleles from exotic or non-adapted donors into elite gene pools during two phases of breeding. In Phase 1, probability functions from the binomial distribution provide at least 95% confidence that a potentially valuable donor allele (A′) will survive two cycles of backcrossing to elite lines and is fixed in BC2-derived lines. During backcrossing, up to 6 major domestication or adaptation genes from the elite parents are reselected and made homozygous in BC2S0 : 1 family rows. Each plant in the BC2S0 : 1 contains on average 12.5% donor alleles, with >95% probability that a particular donor allele is homozygous in at least one fully domesticated plant in the BC2S0 : 1 population. Plants in these rows or subsequent field trials are selected for valuable quantitative traits, and crossed into elite germplasm to commence Phase 2. Phase 1 is rapid and relatively low cost, and provides a continuous flow of novel genetic diversity into the elite breeding pool.

Identification of anthracnose resistance in Lupinus albus L. and its transfer from landraces to modern cultivars

Anthracnose is a major disease of lupins in Western Australia (WA). The disease wiped out the WA albus lupin industry in 1996 and since then, anthracnose resistance has been a major focus for WA lupin breeding. In an endeavour to find a source of resistance to anthracnose, all available germplasm in WA was screened against anthracnose in New Zealand over the summer of 1997 and 1998, and resistance was identified in Ethiopian landraces. The resistance was present in many Ethiopian landraces within a close geographical distribution, suggesting a similar genetic basis of resistance. Crosses were made between the resistant landraces and agronomically superior lines. The progeny were tested for anthracnose resistance, yield, seed quality, and other agronomic characters. The most superior line, Andromeda, was released for commercial production in WA. It was developed from an F3-derived single-plant selection of a cross between an anthracnose-resistant landrace P27175 from Ethiopia and a well adapted but highly susceptible WA breeding line 89B10A-14. Andromeda has a significantly higher level of resistance to anthracnose than the previous cv. Kiev Mutant and is recommended in the medium- to low-rainfall area of the northern wheatbelt of WA. Further breeding effort has resulted in significant improvement in the level of resistance within the WA breeding program, and early generation lines are more resistant than advanced lines. The best resistant lines are, however, in a late flowering background and only an incremental improvement has been achieved in combining early flowering with anthracnose resistance, which seems to be a complex process.

Lupin: the largest grain legume crop in Western Australia, its adaptation and improvement through plant breeding

Between 500 000 and 1 000 000 tonnes of narrow-leafed lupins (Lupinus angustifolius L.) are produced in Western Australia each year. It has become the predominant grain legume in Western Australian agriculture because it is peculiarly well adapted to acid sandy soils and the Mediterranean climate of south-western Australia. It has a deep root system and root growth is not reduced in mildly acid soils, which allows it to fully exploit the water and nutrients in the deep acid sandplain soils that cover much of the agricultural areas of Western Australia. It copes with seasonal drought through drought escape and dehydration postponement. Drought escape is lupins main adaptation to drought, and has been strengthened by plant breeders over the past 40 years by removal of the vernalisation requirement for flowering, and further selection for earlier flowering and maturity. Lupin postpones dehydration by several mechanisms. Its deep root system allows it to draw on water from deep in the soil profile. Lupin stomata close to reduce crop water demand at a higher leaf water potential than wheat, but photosynthetic rates are higher when well watered. It has been proposed that stomata close in response to roots sensing receding soil moisture, possibly at a critical water potential at the root surface. This is an adaptation to sandy soils, which hold a greater proportion of their water at high matric potentials than loamy or clayey soils, since the crop needs to moderate its water use while there is still sufficient soil water left to complete its life cycle. Lupin has limited capacity for osmotic adjustment, and does not tolerate dehydration as well as other crops such as wheat or chickpea. Plant breeding has increased the yield potential of lupin in the main lupin growing areas of Western Australia by 2-3 fold since the first adapted cultivar was released in 1967. This has been due largely to selecting earlier flowering and maturing cultivars, but also to improved pod set and retention, resistance to Phomopsis leptostromiformis (Kuhn) Bubak, and more rapid seed filling. We propose a model for reproductive development in lupin where vegetative growth is terminated in response to receding soil moisture and followed by a period in which all assimilate is devoted to seed filling. This should allow lupin to adjust its developmental pattern in response to seasonal conditions to something like the optimum that mathematical optimal control theory would choose for that season. This is the type of pattern that has evolved in lupin, and the task of future plant breeders will be to fine-tune it to better suit the environment in the lupin growing areas of Western Australia.

The essential role of genetic resources in narrow-leafed lupin improvement

Abstract. The narrow-leafed lupin (Lupinus angustifolius L.) is a legume with much to offer to agriculture and human wellbeing through its adaptation to nitrogen- and phosphorus-deficient, acid, sandy soils, and production of nutritious, very low glycemic index grain with manifold health benefits. However, the industry has exploited only a small fraction of the genetic and adaptive diversity of the species, reflecting a short and fragmented domestication history. Given declining global production, unlocking the potential residing in untapped sources of genetic diversity to maximise yield and value is critical for the future of the crop. To this end, a wide range of genetic resources is under evaluation. The Australian Lupin Collection comprises almost 4600 diverse, mostly wild accessions, many of which have been genotyped using DArT (Diversity Array Technology) markers, and collection sites characterised to facilitate ecophysiology of contrasting material. Additional exotic genetic resources include recombinant inbred line and mutant populations, as well as inter-specific crosses. These resources are being used to investigate specific adaptation and genetic and molecular control of key traits, all of which will be expedited by current efforts to provide a reference genome sequence for L. angustifolius. Genetic base broadening is the current breeding focus, combining distantly related wild and domestic material with elite cultivars in double-backcrosses or topcrosses, with dramatic effects on yield. In future this will be complemented by marker-based, targeted trait introgression to improve narrow-leafed lupin adaptation, quality/value, and fit into the farming system.