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Summary: The afila (af) mutation causes the replacement of leaflets by a branched mass of tendrils in the compound leaves of pea – Pisum sativum L. This mutation was first described in 1953, and several reports of spontaneous af mutations and induced mutants with a similar phenotype exist. Despite widespread introgression into breeding material, the nature of af and the origin of the alleles used remain unknown.Here, we combine comparative genomics with reverse genetic approaches to elucidate the genetic determinants of af. We also investigate haplotype diversity using a set of AfAf and afaf cultivars and breeding lines and molecular markers linked to seven consecutive genes.Our results show that deletion of two tandemly arranged genes encoding Q‐type Cys(2)His(2) zinc finger transcription factors, PsPALM1a and PsPALM1b, is responsible for the af phenotype in pea. Eight haplotypes were identified in the af‐harbouring genomic region on chromosome 2. These haplotypes differ in the size of the deletion, covering more or less genes.Diversity at the af locus is valuable for crop improvement and sheds light on the history of pea breeding for improved standing ability. The results will be used to understand the function of PsPALM1a/b and to transfer the knowledge for innovation in related crops. [ABSTRACT FROM AUTHOR]

In order to gain an understanding of the genetic basis of traits of interest to breeders, the pea varieties Brutus, Enigma and Kahuna were selected, based on measures of their phenotypic and genotypic differences, for the construction of recombinant inbred populations. Reciprocal crosses were carried out for each of the three pairs, and over 200 F2 seeds from each cross advanced to F13. Bulked F7 seeds were used to generate F8–F11 bulks, which were grown in triplicated plots within randomized field trials and used to collect phenotypic data, including seed weight and yield traits, over a number of growing seasons. Genetic maps were constructed from the F6 generation to support the analysis of qualitative and quantitative traits and have led to the identification of four major genetic loci involved in seed weight determination and at least one major locus responsible for variation in yield. Three of the seed weight loci, at least one of which has not been described previously, were associated with the marrowfat seed phenotype. For some of the loci identified, candidate genes have been identified. The F13 single seed descent lines are available as a germplasm resource for the legume and pulse crop communities. [ABSTRACT FROM AUTHOR]

Nuclear magnetic resonance (NMR) spectroscopy profiling was used to provide an unbiased assessment of changes to the metabolite composition of seeds and to define genetic variation for a range of pea seed metabolites. Mature seeds from recombinant inbred lines, derived from three mapping populations for which there is substantial genetic marker linkage information, were grown in two environments/years and analyzed by non-targeted NMR. Adaptive binning of the NMR metabolite data, followed by analysis of quantitative variation among lines for individual bins, identified the main genomic regions determining this metabolic variability and the variability for selected compounds was investigated. Analysis by t-tests identified a set of bins with highly significant associations to genetic map regions, based on probability (p) values that were appreciably lower than those determined for randomized data. The correlation between bins showing high mean absolute deviation and those showing low p-values for marker association provided an indication of the extent to which the genetics of bin variation might be explained by one or a few loci. Variation in compounds related to aromatic amino acids, branched-chain amino acids, sucrose-derived metabolites, secondary metabolites and some unidentified compounds was associated with one or more genetic loci. The combined analysis shows that there are multiple loci throughout the genome that together impact on the abundance of many compounds through a network of interactions, where individual loci may affect more than one compound and vice versa. This work therefore provides a framework for the genetic analysis of the seed metabolome, and the use of genetic marker data in the breeding and selection of seeds for specific seed quality traits and compounds that have high commercial value. [ABSTRACT FROM AUTHOR]

One of the traits studied by Mendel in pea (Pisum sativum L.) was the wrinkled-seeded phenotype, and the molecular basis for a mutation underlying this phenotype was discovered in the 1990s. Although the starch-branching enzyme gene mutation identified at the genetic locus r is most likely to be that in seeds available to Mendel in the mid-1800s, it has remained an open question as to whether or not additional natural mutations in this gene exist within Pisum germplasm collections. Here, we explore this question and show that all but two wrinkled-seeded variants in one such collection correspond to either the mutant allele described previously for the r locus or a mutation at a second genetic locus, rb, affecting the gene encoding the large subunit of Adenosine diphosphoglucose (ADP-glucose) pyrophosphorylase; the molecular basis for the rb mutation is described here. The genetic basis for the phenotype of one (JI 2110) of the two lines which are neither r nor rb has been studied in crosses with a round-seeded variant (JI 281); for which extensive genetic marker data were expected. In marked contrast to the trait studied by Mendel and the rb phenotype; the data suggest that the wrinkled-seeded phenotype in JI 2110 is maternally determined, controlled by two genetic loci, and the extent to which it is manifested is very sensitive to the environment. Metabolite analysis of the cotyledons of JI 2110 revealed a profile for sucrose and sucrose-derived compounds that was more similar to that of wild-type round-seeded, than that of wrinkled-seeded r, pea lines. However, the metabolite profile of the seed coat (testa) of JI 2110 was distinct from that of other round-seeded genotypes tested which, together with analysis of recombinant inbred progeny lines, suggests an explanation for the seed phenotype. [ABSTRACT FROM AUTHOR]

Recent advances in genomics and associated disciplines like bioinformatics have made it possible to develop genomic resources, such as large-scale sequence data for any crop species. While these datasets have been proven very useful for the understanding of genome architecture and dynamics as well as facilitating the discovery of genes, an obligation for, and challenge to the scientific community is to translate genome information to develop products, i.e. superior lines for trait(s) of interest. We call this approach, “translational genomics in agriculture” (TGA). TGA is currently in practice for cereal crops, such as maize (Zea mays) and rice (Oryza sativa), mainly in developed countries and by the private sector; progress has been slow for legume crops. Grown globally on 62.8 million ha with a production of 53.2 million tons and a value of nearly 24.2 billion dollars, the majority of these legumes have low crop productivity (<1 ton/ hectare) and are in the developing countries of sub Saharan Africa, Asia and South America. Interestingly, the last five years have seen enormous progress in genomics for these legume crops. Therefore, it is time to implement TGA in legume crops in order to enhance crop productivity and to ensure food security in developing countries. Prospects, as well as some success stories of TGA, in addition to advances in genomics, trait mapping and gene expression analysis are discussed for five leading legume crops, chickpea (Cicer arietinum), common bean (Phaseolus vulgaris), groundnut (Arachis hypogaea), pigeonpea (Cajanus cajan) and soybean (Glycine max). Some efforts have also been outlined to initiate/ accelerate TGA in three additional legume crops namely faba bean (Vicia faba), lentil (Lens culinaris) and pea (Pisum sativum). [ABSTRACT FROM PUBLISHER]

A fast neutron (FN)-mutagenised population was generated in Pisum sativum L. (pea) to enable the identification and isolation of genes underlying traits and processes. Studies of several phenotypic traits have clearly demonstrated the utility of the resource by associating gene deletions with phenotype followed by functional tests exploiting additional mutant sources, from both induced and natural variant germplasm. For forward genetic screens, next generation sequencing methodologies provide an opportunity for identifying genes associated with deletions rapidly and systematically. The application of rapid reverse genetic screens of the fast neutron mutant pea population supports conclusions on the frequency of deletions based on phenotype alone. These studies also suggest that large deletions affecting one or more loci can be non-deleterious to the pea genome, yielding mutants that could not be obtained by other means. Deletion mutants affecting genes associated with seed metabolism and storage are providing unique opportunities to identify the products of complex and related gene families, and to study the downstream consequences of such deletions. [ABSTRACT FROM AUTHOR]

Plants exhibit various kinds of movements that have fascinated scientists and the public for centuries. Physiological studies in plants with the so-called motor organ or pulvinus suggest that cells at opposite sides of the pulvinus mediate leaf or leaflet movements by swelling and shrinking. How motor organ identity Is determined is unknown. Using a genetic approach, we isolated a mutant designated elongated petiolulel 1(e/pi) from Medicago truncatula that fails to fold its leaflets in the dark due to loss of motor organs. Map-based cloning indicated that ELP1 encodes a putative plant-specific LOB domain transcription factor. RNA in situ analysis revealed that ELP1 is expressed in primordial cells that give rise to the motor organ. Ectopic expression of ELP1 resulted in dwarf plants with petioles and rachises reduced in length, and the epidermal cells gained characteristics of motor organ epidermal cells. By identifying ELP1 orthologs from other legume species, namely pea (Pisum sativum) and Lotus japonicus, we show that this motor organ identity is regulated by a conserved molecular mechanism. [ABSTRACT FROM AUTHOR]

Pea (Pisum sativum L.) has a compound leaf like many other legume species. The 'semi-leafless' pea (afaf TLTL), with all leaflets transformed into tendrils, is considered one of the most important achievements in pea breeding, due to a significantly enhanced standing ability and equally efficient dry matter production in comparison to normal-leafed genotypes (AFAF TLTL). 'Semi-leafless' cultivars provide high and stable grain yield and are dominant in the modern dry pea production worldwide. There are also 'semi-leafless' cultivars that are autumn-sown and those for forage production. The genotypes with all tendrils transformed into leaflets (AFAF tltl), called 'acacia' or 'tendril-less', are extremely prone to lodging and may have importance in breeding for forage production. Little is known about the potential agronomic value of 'acacia-tendril-less' (afaf tltl) genotypes. [ABSTRACT FROM AUTHOR]

The tribe Fabeae (formerly Vicieae) contains some of humanity's most important grain legume crops, namely Lathyrus (grass pea/sweet pea/chickling vetches; about 160 species); Lens (lentils; 4 species); Pisum (peas; 3 species); Vicia (vetches; about 140 species); and the monotypic genus Vavilovia. Reconstructing the phylogenetic relationships within this group is essential for understanding the origin and diversification of these crops. Our study, based on molecular data, has positioned Pisum genetically between Vicia and Lathyrus and shows it to be closely allied to Vavilovia. A study of phylogeography, using a combination of plastid and nuclear markers, suggested that wild pea spread from its centre of origin, the Middle East, eastwards to the Caucasus, Iran and Afghanistan, and westwards to the Mediterranean. To allow for direct data comparison, we utilized model-based Bayesian Analysis of Population structure (BAPS) software on 4429 Pisum accessions from three large world germplasm collections that include both wild and domesticated pea analyzed by retrotransposon-based markers. An analysis of genetic diversity identified separate clusters containing wild material, distinguishing Pisum fulvum, P. elatius and P. abyssinicum, supporting the view of separate species or subspecies. Moreover, accessions of domesticated peas of Afghan, Ethiopian and Chinese origin were distinguished. In addition to revealing the genetic relationships, these results also provided insight into geographical and phylogenetic partitioning of genetic diversity. This study provides the framework for defining global Pisum germplasm diversity as well as suggesting a model for the domestication of the cultivated species. These findings, together with gene-based sequence analysis, show that although introgression from wild species has been common throughout pea domestication, much of the diversity still resides in wild material and could be used further in breeding. Moreover, although existing collections contain over 10,000 pea accessions, effort should be directed towards collecting more wild material in order to preserve the genetic diversity of the species. [ABSTRACT FROM PUBLISHER]

The article examines research on the role of plant transcription factors (TF) in adaptive variation. Control of genetic transcription is attributed to the combined activity of multiple TF binding to cis-elements in their promoters. Strategies for engineering plants in the future are expected to be influenced by the possible evolution of phenotypic variation through changes in genes encoding lower-order TF. It suggests exploring lower-order regulators of cell development and metabolism to engineer plant traits.

Biparental recombinant inbred line (RIL) populations are sets of genetically stable lines and have a simple population structure that facilitates the dissection of the genetics of interesting traits. On the other hand, populations derived from multiparent intercrosses combine both greater diversity and higher numbers of recombination events than RILs. Here, we describe a simple population structure: a three-way recombinant inbred population combination. This structure was easy to produce and was a compromise between biparental and multiparent populations. We show that this structure had advantages when analyzing cultivar crosses, and could achieve a mapping resolution of a few genes. [ABSTRACT FROM AUTHOR]

Tendrils are contact-sensitive, filamentous organs that permit climbing plants to tether to their taller neighbors. Tendrilled legume species are grown as field crops, where the tendrils contribute to the physical support of the crop prior to harvest. The homeotic tendril-less (tl) mutation in garden pea (Pisum sativum), identified almost a century ago, transforms tendrils into leaflets. In this study, we used a systematic marker screen of fast neutron-generated tl deletion mutants to identify TI as a Class I homeodomain leucine zipper (HDZIP) transcription factor. We confirmed the tendril-less phenotype as loss of function by targeting induced local lesions in genomes (TILLING) in garden pea and by analysis of the tendril-less phenotype of the t mutant in sweet pea (Lathyrus odoratus). The conversion of tendrils into leaflets in both mutants demonstrates that the pea tendril is a modified leaflet, inhibited from completing laminar development by TI. We provide evidence to show that lamina inhibition requires Unifoliata/LEAFY-mediated TI expression in organs emerging in the distal region of the leaf primordium. Phylogenetic analyses show that TI is an unusual Class I HDZIP protein and that tendrils evolved either once or twice in Papilionoid legumes. We suggest that tendrils arose in the Fabeae clade of Papilionoid legumes through acquisition of the TI gene. [ABSTRACT FROM AUTHOR]

The model plants Arabidopsis (Arabidopsis thaliana) and rice (Oryza sativa) have provided a wealth of information about genes and genetic pathways controlling the flowering process, but little is known about the corresponding pathways in legumes. The garden pea (Pisum sativum) has been used for several decades as a model system for physiological genetics of flowering, but the lack of molecular information about pea flowering genes has prevented direct comparison with other systems. To address this problem, we have searched expressed sequence tag and genome sequence databases to identify flowering-gene-related sequences from Medicago truncatula, soybean (Glycine max), and Lotus japonicus, and isolated corresponding sequences from pea by degenerate-primer polymerase chain reaction and library screening. We found that the majority of Arabidopsis flowering genes are represented in pea and in legume sequence databases, although several gene families, including the MADS-box, CONSTANS, and FLOWERING LOCUS T / TERMINAL FLOWER1 families, appear to have undergone differential expansion, and several important Arabidopsis genes, including FRIGIDA and members of the FLOWERING LOCUS C clade, are conspicuously absent. In several cases, pea and Medicago orthologs are shown to map to conserved map positions, emphasizing the closely syntenic relationship between these two species. These results demonstrate the potential benefit of parallel model systems for an understanding of flowering phenology in crop and model legume species. [ABSTRACT FROM AUTHOR]

Legumes are simultaneously one of the largest families of crop plants and a cornerstone in the biological nitrogen cycle. We combined molecular and phylogenetic analyses to evaluate genome conservation both within and between the two major clades of crop legumes. Genetic mapping of orthologous genes identifies broad conservation of genome macrostructure, especially within the galegoid legumes, while also highlighting inferred chromosomal rearrangements that may underlie the variation in chromosome number between these species. As a complement to comparative genetic mapping, we compared sequenced regions of the model legume Medicago truncatula with those of the diploid Lotus japonicus and the polyploid Glycine max. High conservation was observed between the genomes of M. truncatula and L. japonicus, whereas lower levels of conservation were evident between M. truncatula and G. max. In all cases, conserved genome microstructure was punctuated by significant structural divergence, including frequent insertion/deletion of individual genes or groups of genes and lineage-specific expansion/contraction of gene families. These results suggest that comparative mapping may have considerable utility for basic and applied research in the legumes, although its predictive value is likely to be tempered by phylogenetic distance and genome duplication. [ABSTRACT FROM AUTHOR]

In the last few years, we have seen a growing emphasis on the characterisation of germplasm collections by molecular markers such as microsatellites, AFLPs, SSAPs, RBIPs and SNPs. This emphasis has served to enhance the use of germplasm collections in crop improvement via plant breeding while also aiding the management of collections themselves through an improved understanding of the relationships between accessions and underlying patterns of diversity. With the new data sets becoming available comes the recognition of the role that bioinformatics can play in making the most of the data. The basis of the new bioinformatics infrastructure is databases that enable the association of passport and trait data with molecular markers. Visualisation tools enable us to view large quantities of these data simultaneously and to tease out patterns underlying our data sets. We also need analytical tools to help us search for trait-marker or haplotype-marker associations and to look for patterns of genetic diversity. Most importantly, all of these components should interact in a fluid and intuitive manner such that the developers of germplasm collections and the plant genetics and breeding communities can access and manipulate the data. Here, we focus on the development of new bioinformatics tools for germplasm analysis within two projects: GENE-MINE and GERMINATE. We look at different aspects of our bioinformatics infrastructure, to give a sense of the powerful analyses that bioinformatics can facilitate. Finally, we look forward to bringing together these different areas to the benefit of the plant breeding and genetic resources communities. [ABSTRACT FROM AUTHOR]

A high throughput proton nuclear magnetic resonance spectroscopy method for the metabolite fingerprinting of plants was applied to genetically modified peas ( Pisum sativum) to determine whether biochemical changes, so called ‘unintended effects’, beyond those intended by incorporation of a transgene, were detectable. Multivariate analysis of 1H NMR (nuclear magnetic resonance) spectra obtained from uniformly grown glasshouse plants revealed differences between the transgenic and control group that exceeded the natural variation of the plants. When a larger data set of six related transgenic lines was analysed, including a null segregant in addition to the wild-type control, multivariate analysis showed that the distribution of metabolites in the transgenics was different from that of the null segregant. However, the profile obtained from the wild-type material was diverse in comparison with both the transgenics and the null segregant, suggesting that the primary cause of the observed differences was that the transformation process selects for a subset of individuals able to undergo the transformation and selection procedures, and that their descendants have a restricted variation in metabolite profile, rather than that the presence of the transgene itself generates these differences. [ABSTRACT FROM AUTHOR]

Genes in the TERMINAL FLOWER1 (TFL1)/CENTRORADIALIS family are important key regulatory genes involved in the control of flowering time and floral architecture in several different plant species. To understand the functions of TFL1 homologs in pea, we isolated three TFL1 homologs, which we have designated PsTFL1a, PsTFL1b, and PsTFL1c. By genetic mapping and sequencing of mutant alleles, we demonstrate that PsTFL1a corresponds to the DETERMINATE (DET) gene and PsTFL1c corresponds to the LATE FLOWERING (LF) gene. DET acts to maintain the indeterminacy of the apical meristem during flowering, and consistent with this role, DET expression is limited to the shoot apex after floral initiation. LF delays the induction of flowering by lengthening the vegetative phase, and allelic variation at the LF locus is an important component of natural variation for flowering time in pea. The most severe class of alleles flowers early and carries either a deletion of the entire PsTFL1c gene or an amino acid substitution. Other natural and induced alleles for LF, with an intermediate flowering time phenotype, present no changes in the PsTFL1c amino acid sequence but affect LF transcript level in the shoot apex: low LF transcript levels are correlated with early flowering, and high LF transcript levels are correlated with late flowering. Thus, different TFL1 homologs control two distinct aspects of plant development in pea, whereas a single gene, TFL1, performs both functions in Arabidopsis. These results show that different species have evolved different strategies... [ABSTRACT FROM AUTHOR]

Discusses phenotypic analysis of pea sym35 mutants and Lotus japonicus nin mutants. Stages of root nodule formation; Developmental regulation of the PsNin and LjNin genes; Expression of PsNin in the meristematic cells.

Genes representative of three gene classes encoding proteinase inhibitor proteins, with distinct spatial expression patterns, were isolated and characterized from Pisum.Under standard plant growth conditions, one class is expressed exclusively in seeds, whereas the other two make minor contributions to seed inhibitor proteins but are also expressed in other organs, predominantly in root endodermal and floral reproductive tissues. Two of the gene classes contain few genes and are genetically linked at the Tri locus, whereas the third class displays complex hybridization patterns to genomic DNA and maps to diverse genetic loci. Expression analysis of this last class suggests that only a small number of these genes are expressed. The quantitative effect of the Tri locus on root and floral inhibitor gene expression was examined in near-isogenic lines of pea. The proteins encoded by the three classes are all members of the same family (Bowman-Birk) of enzyme inhibitors but are distinct in terms of overall sequence, active site sequences and inhibitor function. [ABSTRACT FROM AUTHOR]

A cDNA clone, pCD7, was shown to hybrid-select from developing seeds of Pisum sativum L. an mRNA that translated into a polypeptide of apparent M 90 000. The translation product was observed only in the earliest stages of embryogenesis and was detected at a developmental stage when virtually all the cotyledon cells are mitotic. Sequence analysis of pCD7 showed it to correspond to a member of the 70 000-M heat-shock protein (HSP70) gene family. Transcripts corresponding to pCD7 were detected in different P. sativum organs, with roots apparently showing lower levels of pCD7-homologous RNA than other organs. Hybridizations to P. sativum DNA identified polymorphisms in the genomic DNA corresponding to pCD7 and the segregation of these in selected crosses indicated the existence of at least two genetic loci, one of which mapped to an existing linkage group. [ABSTRACT FROM AUTHOR]