Susana T. Leitao

Allelic diversity in the transcriptomes of contrasting rust-infected genotypes of Lathyrus sativus, a lasting resource for smart breeding

BackgroundGrass pea (Lathyrus sativus L.) is a valuable resource for potentially durable partial resistance to rust. To gain insight into the resistance mechanism and identify potential resistance genes, we generated the first comprehensive transcriptome assemblies from control and Uromyces pisi inoculated leafs of a susceptible and a partially rust-resistant grass pea genotype by RNA-seq.Results134,914 contigs, shared by both libraries, were used to analyse their differential expression in response to rust infection. Functional annotation grouped 60.4% of the contigs present in plant databases (37.8% of total) to 33 main functional categories, being “protein”, “RNA”, “signalling”, “transport” and “stress” the most represented. Transcription profiles revealed considerable differences in regulation of major phytohormone signalling pathways: whereas Salicylic and Abscisic Acid pathways were up-regulated in the resistant genotype, Jasmonate and Ethylene pathways were down-regulated in the susceptible one. As potential Resistance-genes we identified a mildew resistance locus O (MLO)-like gene, and MLO-related transcripts. Also, several pathogenesis-related genes were up-regulated in the resistant and exclusively down regulated in the susceptible genotype. Pathogen effectors identified in both inoculated libraries, as e.g. the rust Rtp1 transcript, may be responsible for the down-regulation of defence-related transcripts. The two genotypes contained 4,892 polymorphic contigs with SNPs unevenly distributed between different functional categories. Protein degradation (29.7%) and signalling receptor kinases (8.2%) were the most diverged, illustrating evolutionary adaptation of grass pea to the host/pathogens arms race.ConclusionsThe vast array of novel, resistance-related genomic information we present here provides a highly valuable resource for future smart breeding approaches in this hitherto under-researched, valuable legume crop.

A Quantitative Structure−Property Relationship Study of the Release of Some Esters and Alcohols from Barley and Oat β-Glucan Matrices

This study investigates the release of selected strawberry flavor compounds from aqueous solutions of two barley and oat beta-glucan products at concentrations of 5, 10, and 15% (w/w). The flavor release of 12 esters and 3 alcohols was measured by dynamic headspace GC-MS. For each compound the ratio of the flavor release from the beta-glucan solution to the release from aqueous solution, A(rel), was recorded. In general, esters were retained in the beta-glucan matrices in a mass-dependent manner where heavier molecules were retained more. A(rel) for alcohols was found to be significantly larger than for the esters. Whereas A(rel) values for esters were always below unity, this parameter was above unity for alcohols in some preparations of beta-glucan. This implies that relative to esters, alcohols were rejected from some matrices. An increase in the concentration of the beta-glucan products was associated with an increased retention of alcohols and esters. For solutions of oat and barley beta-glucan products at the same concentration, the oat product retained the flavor compounds more strongly. This difference was more pronounced at low concentrations of the beta-glucan products. To investigate the potential of a multivariate approach for the analysis of the flavor release from beta-glucan products, partial least-squares regression was employed on a large selection of calculated molecular descriptors, yielding simple QSPR models capable of explaining the variation in A(rel). The robustness of the QSPR models was verified by cross-validation and permutation tests. The results indicate that the multivariate modeling approach might provide a useful tool for the investigation of flavor release systems similar to those studied here.

Deciphering Grain Legumes Quality Riddle: The Genomics of Bioactive Compounds

Grain legumes are a vital source of inexpensive plant-based proteins and amino acids and, eaten as part of a healthy diet, they help to prevent chronic diseases. Potential health benefits of grain legumes have been mainly attributed to the presence of secondary metabolites with antioxidant activity. Breeding for improved end-user’s quality is a complex task due to trait interaction. Some of these metabolites, such as phenolic compounds, that act as health-promoting agents are also considered antinutrients, influencing both taste and consumers’ acceptability. Under the scope of LEGATO and BEGEQA projects, we studied the genetic architecture of the total phenolic compounds content in grass pea and common bean seeds. Association mapping approaches were applied to both common bean and grass pea germplasm collections and the genomic regions controlling these bioactive compounds concentration were identified. This work will contribute to the development of grain legume varieties with better nutritional quality, meeting consumers’ expectations at the same time that support the improvement and production of a plant resource with a vital role in sustainable agriculture.

Elucidation of the rust resistance genetic control in Portuguese common bean through a genime-wide association study

Trabajo presentado en el 15th Congress of the Mediterranean Phytopathological Union, celebrado en cordoba (Espana) del 20 al 23 de junio de 2017.Comunicacion oral presentada en el 15th Congress of the Mediterranean Phytopathological Union, June 20–23, 2017, Cordoba, Spain.Early assessment of late wilt of maize (Harpophora maydis) and the control effect of Lycium europaeum extracts. C. RODRÍGUEZ-MALLOL1, R. TEJ1,2, L. MOLINERO-RUIZ1. 1Department of Crop Protection, Institute for Sustainable Agriculture (IAS), Spanish National Research Council (CSIC), Alameda del Obispo s/n, 14004 Córdoba, Spain. 2Physiology and Biochemistry of Plant Response to Abiotic Stresses Unit, Faculty of Sciences of Tunis, University of Tunis El Manar, 1060 Tunis El Manar, Tunisia. E-mail: lmolinero@ias.csic.es