Nitrogen Fixer Cultivation details An easily grown plant, succeeding in any moderately good garden soil but preferring a position in full sun. Plants are cultivated in southern Europe for their edible seed. Closely related to L. This species has a symbiotic relationship with certain soil bacteria, these bacteria form nodules on the roots and fix atmospheric nitrogen.
|Published (Last):||2 December 2008|
|PDF File Size:||18.92 Mb|
|ePub File Size:||20.8 Mb|
|Price:||Free* [*Free Regsitration Required]|
Genetic markers Abstract The Lathyrus cicera transcriptome was analysed in response to rust Uromyces pisi infection to develop novel molecular breeding tools with potential for genetic mapping of resistance in this robust orphan legume species.
One RNA-seq library each was generated from control and rust-inoculated leaves from two L. In addition, we developed and tested expressed E-SSR markers from the contigs, of which A first L.
This map contains markers, covered The genic markers also enabled us to compare their position in L. This study provides a large new set of genic polymorphic molecular markers with potential for mapping rust resistances. It represents the first step towards genomics-assisted precision breeding in L.
It is mainly grown as feedstock, both as fodder and grain 3. However, as far as human consumption is concerned, L. It is resistant to drought, waterlogging 5 and to several important legume pathogens.
Sources for resistance to rust 6 , powdery mildew 7 , bacterial blight 8 and crenate broomrape 9 have been identified. Thus, L. A linkage map of L. Indeed, limited genomic resources exist for this plant species, hampering its potential exploitation in legume breeding.
However, molecular tools from related species were useful in this legume. Actually, molecular markers of different types previously developed for other legume species, were successfully cross-amplified in L. Rust fungi and particularly those from the genus Uromyces cause important legume diseases.
Uromyces pisi Pers. Lathyrus sativus is the species most closely related to L. We have recently characterised in more detail the response of L. Differences in the reaction to infection between the resistant and susceptible genotypes investigated appeared to be mainly due to the activation of the salicylic acid SA pathway and expression of several pathogenesis-related PR genes.
Indeed, in previous studies both species, L. Also, similar defence mechanisms were present, although L. In the present work, we investigate the transcriptomes of control and rust-inoculated leaves from two L. Finally, we used the developed L.
This map was developed using a recombinant inbred line RIL population resulting from the cross of the two contrasting L. The respective library from the partially resistant genotype BGE comprised 30,, reads, which assembled into 64, contigs, with a size range of to bp and a mean contig length of bp. A total of 20, contigs were unique to the partially resistant and 12, contigs were unique to the susceptible genotype. Differential gene expression in partially resistant and susceptible L.
Groups with most abundant contigs were group F contigs downregulated in both genotypes and H contigs downregulated only in the partially resistant genotype with and contigs, respectively.
They were followed by a group that included entries upregulated upon infection in both genotypes group A. As depicted in Supplementary Fig. S1 , from the , contigs that could be identified and quantified, 43, were shared among all libraries. Table 1 Classification of contigs according to their differential expression in the susceptible and resistant genotype upon infection with U. A total of 0. In addition to these, 0. Thus, a total of 1. As indicated in Fig. Medicago truncatula 23,; Vitis vinifera 1,; 2.
A total of CHO: carbohydrate, OPP: oxidative pentose phosphate, TCA: tricarboxylic acid, ATP: adenosine triphosphate Full size image The analysis of the identified functional categories revealed transcripts that are potentially involved in several layers of defence against pathogens Although a detailed description of these differentially expressed transcripts is not under the main scope of this study that focus on the identification of potential molecular markers useful for mapping, we emphasise those upregulated in response to rust infection only in the partially resistant genotype.
This group included transcripts involved in hormone metabolism, cell wall degradation, secondary metabolism, ROS production and in signalling and regulation of transcription of defence responses.
Also related to signalling, but in the group of transcripts upregulated in the susceptible and downregulated in the partially resistant genotype, a MLO-like transcript AtMLO6, PsMLO1, a;11 was identified. The number of SNPs in functional categories varied considerably. Allele-specific expression validation by dual probe assays Seventeen allele-specific expression assays were tested for their ability to distinguish the two alleles in the genotypes BGE and BGE For eight SNP sites, the allele-specific expression could be confirmed for both alleles a;, a;, a;85, a;, a;, a;, a; and a; In five cases only one of the two alleles could be unambiguously amplified a;, a;, a;97, a; and a; Of these, produced an amplicon, where Thirty-one 9.
The remaining markers presented a high segregation distortion and were excluded from further analysis. A total of SNPs was then selected for developing the linkage map. From the remaining markers, 66 were removed for having identical segregation to other markers, thus redundant for the map construction. Finally, the first L. It covered Only 5 markers could not be linked to any other LG. Eleven percent of the markers showed significant deviation from the expected segregation ratio segregation distortion , highlighted with asterisks in Fig.
A chromosomal region was considered skewed when four or more closely linked markers showed significant segregation distortion in the same direction Genetic distances given in cM Kosambi mapping function on the left. Marker names are shown on the right of each linkage group. Macrosynteny between L. Clear evidence of a simple and direct macrosynteny between the L.
The clear isoclinic diagonal line along the linkage groups in Fig. However, chromosomal rearrangements were also evident at a moderate level. For example, M. S3, C and G. Similarly, M. S3, E and H , respectively. Additionally, M. S3, I. The L. The present study contributes to progress in L. First, it provides the sequences of more than , ESTs representing by far the most extended set of genic sequences available for this species.
In addition, it detected potential polymorphic E-SSRs and 19, SNPs in more than 5, transcripts and tested exemplarily whether these could be converted into molecular markers for later use in molecular breeding and their usefulness in the development of the first L.
The development of E-SSR markers was quite successful as it resulted in novel, polymorphic marker assays, some of them we employed already here for the construction of a linkage map for L. Eventually these may also be used, by cross-amplification 11 , for genetic mapping in L.
The many other genic SNPs identified here may also be converted into molecular markers. The observed incongruence between the expected and experimental results in the E-SSR validation may be due to the fact that RNA-seq data provide information only from the exons. Therefore, the reason for the failure of several primer pairs to amplify a sequence at all, may be the presence of large introns between the primer binding sites which are not detectable in our RNA-seq data.
Also, the production of complex patterns of fragments may be due to the existence of regions of homology to the primer binding sites elsewhere in the genome that were then amplified together with the correct fragment. Eventually, primers were located across splice sites or they could be derived from erroneously assembled contigs In any case, the fact that It further demonstrates that the assemblies are correct in most cases.
We expect better results from another system with higher resolution. In previous studies, resistance mechanisms against rust appeared to be similar in incompatible L. In both, L. Still, L. For example, the most resistant L.
Future comparative studies should reveal if the same defence-related genes or QTLs are involved in L. As an example, in L. The MLO gene was first identified in barley, where loss-of-function mutations in this gene conferred resistance to powdery mildew MLO-like genes mediated the vulnerability to several fungal pathogens in Arabidopsis 26 and to powdery mildew in Pisum sativum In our previous study on rust resistance in L. The lack of genomic resources is a common restraint to molecular analysis in orphan crops, and L.
Since we sequenced samples inoculated with rust, we could also identify transcripts that probably have a fungal origin.
Those were 1. As already discussed by Hacquard et al.
Lathyrus odoratus (Sweet Pea)
Genetic markers Abstract The Lathyrus cicera transcriptome was analysed in response to rust Uromyces pisi infection to develop novel molecular breeding tools with potential for genetic mapping of resistance in this robust orphan legume species. One RNA-seq library each was generated from control and rust-inoculated leaves from two L. In addition, we developed and tested expressed E-SSR markers from the contigs, of which A first L. This map contains markers, covered The genic markers also enabled us to compare their position in L. This study provides a large new set of genic polymorphic molecular markers with potential for mapping rust resistances.
Crete , Italy incl. Corsica , Portugal, Spain incl. Baleares References: Afonin, A. Greene, N. Frolov, eds. Interactive agricultural ecological atlas of Russia and neighboring countries. Economic plants and their diseases, pests and weeds on-line resource.