Unveiling common responses of Medicago truncatula to appropriate and inappropriate rust species.

Little is known about the nature of effective defense mechanisms in legumes to pathogens of remotely related plant species. Some rust species are among pathogens with broad host range causing dramatic losses in various crop plants. To understand and compare the different host and nonhost resistance (NHR) responses of legume species against rusts, we characterized the reaction of the model legume Medicago truncatula to one appropriate (Uromyces striatus) and two inappropriate (U. viciae-fabae and U. lupinicolus) rusts. We found that similar pre and post-haustorial mechanisms of resistance appear to be operative in M. truncatula against appropriate and inappropriate rust fungus. The appropriate U. striatus germinated better on M. truncatula accessions then the inappropriate U. viciae-fabae and U. lupinicolus, but once germinated, germ tubes of the three rusts had a similar level of success in finding stomata and forming an appressoria over a stoma. However, responses to different inappropriate rust species also showed some specificity, suggesting a combination of non-specific and specific responses underlying this legume NHR to rust fungi. Further genetic and expression analysis studies will contribute to the development of the necessary molecular tools to use the present information on host and NHR mechanisms to breed for broad-spectrum resistance to rust in legume species.Financial support by Spanish AGL2011-22524 and Portuguese PEst-OE/EQB/LA0004/2011 grants is acknowledged. Maria Carlota Vaz Patto was supported by Fundação para a Ciência e a Tecnologia (Incentivos 2014 program).Peer Reviewe

The genetics and mechanism of avoidance of rust infection in Hordeum chilense

Hordeum chilense is a perennial species occurring in Chile and Argentina. This wild barley species shows a very wide range of variation of morphological and agronomic characters and crosses easily with other members of the Triticeae tribe.H. chilense is one of the five wild barley species in which avoidance of rust fungi as been reported. The avoidance mechanism to rust fungi is characterised by stomata overgrowth by the fungal germ tube, with no appressorium formation or penetration of the stomata, resulting in early failure of the infection process. This avoidance is an interesting mechanism of defence against rust infection, especially when it could be transferred to cultivated cereal species.In this thesis the genetic basis of this avoidance mechanism and associations of avoidance with other characters in H. chilense were established.We tested the hypothesis that the avoidance character occurs in a certain morphologically and molecularly distinct ecotype of H. chilense . A H. chilense collection of 88 accessions was characterised for morphological and agronomic traits, level of avoidance of Puccinia hordei , habitat of origin and AFLP fingerprint. Cluster analysis using both morphological/agronomic and AFLP fingerprint data suggested three distinct clusters of accessions. High avoidance was typical to the accessions of one of these three clusters. The accessions in the cluster with the higher levels of avoidance had been collected in humid habitats. This putative subspecific taxon was further characterised by shorter and wider spikes, more erect culms, a shorter uppermost internode until flag leaf and a greater amount of stomata density on the abaxial leaf side. We conclude that H. chilense consists of at least three rather well defined morphologically and genetically distinct subspecific taxa, one of which has a very high level of avoidance of barley leaf rust.We studied the effect of the cuticular wax layer on the orientation of germ tube growth and on appressorium differentiation of P. hordei . Several orientation parameters and appressorium differentiation of P. hordei germ tubes were measured on H. chilense leaves with and without the wax layer.Removal of the cuticular wax layer did not result in poor and also not in better germ tube orientation. Evidence was obtained that epidermal cell junctions rather than the wax crystals provided the landmarks to guide germ tubes along the transverse axis of the leaf. On high avoidance accessions the removal of the wax layer allowed appressoria to develop over stomata that would otherwise be overgrown. This suggests that the overgrowth of stomata on H. chilense leaves by P. hordei germ tubes is mainly due to the wax covering of the stomatal apparatus.A molecular map of the wild barley H. chilense would greatly facilitate to map and efficiently transfer agronomic traits from H. chilense to cereal genomes. As a first step towards a map construction, we evaluated AFLP markers in H. chilense using diploid wheat ( Triticum monococcum ) and cultivated barley ( H. vulgare ) as references. H. chilense showed a higher percentage of polymorphisms than diploid wheat. It was remarkable that, based on AFLP markers generated by 12 Eco RI/ Mse I primer combinations, the cultivated barley was more similar to diploid wheat than to H. chilense . Even more surprisingly, the genetic distance between the interfertile H. chilense accessions (H1 and H7) was almost as large as the genetic distance between the non-crossable cultivated barley and diploid wheat. Eco RI/ Mse I AFLP fingerprints revealed more polymorphism than Pst I/ Mse I AFLP fingerprints for all species tested and were chosen for generating the first AFLP linkage map of H. chilense .The mapping population consisted of 100 F 2 plants derived from a cross between two genetically distinct H. chilense accessions that were contrasting for the level of avoidance, H1 and H7. The constructed map contained 443 AFLP markers, on nine long and ten shorter linkage groups, covering a genetic distance of 714 cM. Nine of these linkage groups were assigned to H. chilense chromosomes using a set of H. chilense in T. aestivum addition and substitution lines. Strong clustering of AFLP markers was observed at putative centromeric regions. A skeletal map with a uniform distribution of markers was extracted from this linkage map. This skeletal map was applied to detect and map QTLs underlying avoidance and stoma density on the abaxial leaf epidermis.Three QTLs were detected for avoidance and three other QTLs for stoma density. Both traits segregated independently in the F 2 .Avoidance on H. chilense is effective to barley leaf rust, wheat leaf rust and rye leaf rust. As H. chilense shows good crossability with several cultivated cereals avoidance of leaf rusts may be introgressed into these cultivated cereals, especially wheat. Addition and substitution lines of H. chilense in Chinese Spring wheat cv. are already available or being developed as a first step towards transfer of the genes governing the avoidance trait.</p

Calidad de la proteína de las leguminosas grano: un tema candente

Grain legumes, also called pulses, play a key role in the nutritional improvement of food and feed. These legumes are important sources of protein as well as other nutritional compounds. Today, protein is one of the most sought after ingredients in the market and grain legumes represent one of the most sustainable protein sources. However, not all grain legume proteins are nutritionally equal. Their quality varies and depends on their amino acid composition and digestibility. In this article, we review concepts related to grain legume protein quality and discuss challenges regarding their genetic improvement. A comprehensive database of grain legume amino acid profiles and protein digestibility is needed to address the matter of protein quality in grain legume breeding. This database will be enhanced by quantitative information on digestibility-reducing bioactive compounds and the development of reliable screening tools. The achievement of higher protein quality grain legume varieties, better adjusted to animal and human requirements, will cut dietary protein content, associated costs and nitrogen excretion, thus reducing the environmental impact.Las leguminosas grano tienen un alto potencial en alimentación humana y animal siendo una importante fuente de proteínas así como de otros compuestos beneficiosos para la nutrición y salud. La proteína es uno de los ingredientes más demandados y las leguminosas grano son una delas fuentes más sostenible de proteína. Sin embargo, no todas las leguminosas grano son igual de nutritivas, variando la calidad con la composición de aminoácidos y su digestibilidad. En este artículo revisaremos los conceptos de calidad de la proteína y discutiremos las posibilidades de mejora genética. Para abordar con éxito la mejora de la calidad de la proteína será de gran ayuda disponer de bases de datos con los perfiles de aminoácidos y de digestibilidad, así como de información cuantitativa sobre los compuestos bioactivos que reducen la digestibilidad, todo ello unido a métodos fiables para su evaluación. El desarrollo de variedades de leguminosas con una proteína de mayor calidad, más ajustadas a las necesidades tanto humanas como del ganado, permitirá una mayor eficiencia nutritiva, reduciendo el contenido de proteína en la dieta y los costes asociados, así como la excreción de nitrógeno, disminuyendo el impacto medioambiental

Grain legume protein quality: a hot subject

Grain legumes, also called pulses, play a key role in the nutritional improvement of food and feed. These legumes are important sources of protein as well as other nutritional compounds. Today, protein is one of the most sought after ingredients in the market and grain legumes represent one of the most sustainable protein sources. However, not all grain legume proteins are nutritionally equal. Their quality varies and depends on their amino acid composition and digestibility. In this article, we review concepts related to grain legume protein quality and discuss challenges regarding their genetic improvement. A comprehensive database of grain legume amino acid profiles and protein digestibility is needed to address the matter of protein quality in grain legume breeding. This database will be enhanced by quantitative information on digestibility-reducing bioactive compounds and the development of reliable screening tools. The achievement of higher protein quality grain legume varieties, better adjusted to animal and human requirements, will cut dietary protein content, associated costs and nitrogen excretion, thus reducing the environmental impact.<br><br>Las leguminosas grano tienen un alto potencial en alimentación humana y animal siendo una importante fuente de proteínas así como de otros compuestos beneficiosos para la nutrición y salud. La proteína es uno de los ingredientes más demandados y las leguminosas grano son una delas fuentes más sostenible de proteína. Sin embargo, no todas las leguminosas grano son igual de nutritivas, variando la calidad con la composición de aminoácidos y su digestibilidad. En este artículo revisaremos los conceptos de calidad de la proteína y discutiremos las posibilidades de mejora genética. Para abordar con éxito la mejora de la calidad de la proteína será de gran ayuda disponer de bases de datos con los perfiles de aminoácidos y de digestibilidad, así como de información cuantitativa sobre los compuestos bioactivos que reducen la digestibilidad, todo ello unido a métodos fiables para su evaluación. El desarrollo de variedades de leguminosas con una proteína de mayor calidad, más ajustadas a las necesidades tanto humanas como del ganado, permitirá una mayor eficiencia nutritiva, reduciendo el contenido de proteína en la dieta y los costes asociados, así como la excreción de nitrógeno, disminuyendo el impacto medioambiental

Exploring grass pea (Lathyrus sativus L.) genetic diversity in Mediterranean changing climate conditions

Funding Information: This work was supported by the Fundação Para a Ciência e Tecnologia through the grant SFRH/BD/124094/2016 (LG), the R&D Research Unit GREEN-IT—Bioresources for Sustainability (10.54499/UIDB/04551/2020, 10.54499/UIDP/04551/2020) and LS4FUTURE Associated Laboratory (LA/P/0087/2020), by Spanish Research Agency (AEI) project PID2020-11468RB-100 and by the European Union Horizon 2020 Research and Innovation Programme under Grant nº 101000383 (DIVINFOOD). Publisher Copyright: © 2024Grass pea (Lathyrus sativus L.) is an annual cool-season grain legume, recognized as a stress-resilient crop, able to thrive in unfavourable growing conditions. It is widely cultivated in different world regions, with two main ecotypes based on seed traits. Particularly, in the Mediterranean region, climate change has amplified environmental instability, creating a fundamental need for producing more resilient or adaptable plant varieties. With the present study, we aimed to identify, among grass pea germplasm, new sources of interesting agronomic traits that can be used in breeding programs for adaptation to climate change. Hence, we trialled a worldwide grass pea collection of 182 accessions in Alvaiázere, Portugal, a Mediterranean climate region, across four growing seasons. We characterized the accessions for plant growth-, inflorescence-, seed-, and yield-related traits. By applying linear mixed models analysis, we assessed the diversity among accessions, as well as the genotype, the environment, and the genotype-by-environment effects. A principal component analysis was performed to summarize multivariate similarities among grass pea accessions and/or growing seasons. Additionally, we estimated the main ecotype clustering parameters, seed coat colour, seed size, and geographical origin, effects on the measured traits. Great diversity among accessions for all traits was observed. For most traits, the effect of the growing season was the most prominent, although significant genotype and genotype-by-environment interaction effects were also observed. Yield was higher on large and light seed accessions, with no significant yield differences detected across geographical origins. Nevertheless, South Asian accessions showed the tallest plants at the first flower and the highest number of seeds per plant (although with the smallest seed sizes), two of the most important yield components in the study. The Sub-Saharan African accessions showed the shortest growth cycles and mainly dark coat colours, trait associated with a reduced infestation by Bruchus weevils. The last two traits are of great interest as breeding targets. The Sub-Saharan accessions may thus be of significant value as potential donor material in breeding programs.publishersversionpublishe

Impacto da temperatura na biologia reprodutora e condição fisiológica do francelho e rolieiro: implicações para a adaptação às alterções climáticas

Tese de mestrado. Biologia (Ecologia e Gestão Ambiental). Universidade de Lisboa, Faculdade de Ciências, 2014Nos últimos anos, surgiram provas categóricas que demonstram o impacto das alterações climáticas na fenologia, distribuição, biologia reprodutora e dinâmica populacional das aves. No sul de Portugal, cenários climáticos prevêem para o período 2080-2100 um aumento na temperatura média máxima no Verão de 6-7 ºC, um incremento significativo na ocorrência de ondas de calor e uma redução na precipitação. Este estudo pretendeu contribuir para a identificação dos impactos e riscos associados ao aumento da temperatura sobre a biologia reprodutora e condição fisiológica de crias de Francelho (Falco naumanni) e Rolieiro (Coracias garrulus), propondo algumas medidas de adaptação face às alterações previstas. O microclima do ninho desempenhou um papel fundamental na condição fisiológica e crescimento das crias de ambas as espécies. A colocação de caixas-ninho de madeira artificiais na área de estudo contribuiu nos últimos anos para o aumento da população nidificante de Francelhos e Rolieiros. No entanto este estudo demonstrou que presentemente as caixas-ninho de madeira atingem temperaturas que afectam a sobrevivência das crias de Francelho e o crescimento das crias de ambas as espécies. O estudo revelou ainda que o aumento da temperatura do ninho afecta a razão de heterófilos sobre linfócitos (H/L) em crias de Francelho. As crias de Francelho sujeitas a temperaturas mais elevadas apresentaram um índice de stress H/L superior às restantes. Face ao aumento da temperatura previsto nos cenários climáticos futuros para o Mediterrâneo torna-se fundamental substituir este tipo de ninho na área de estudo por outros com condições térmicas mais favoráveis ao sucesso reprodutor de ambas as espécies.In recent years, compelling evidence has been found for the impact of climate change on geographical distribution, phenology, breeding biology and population dynamics of many bird species. In Southern Portugal, climate scenarios predict an increase in average maximum summer temperature of 6-7 °C for the period 2080-2100, a significant increase in the occurrence of heat waves and a reduction in precipitation. This study aims to contribute to the identification of impacts and risks associated with the increase in temperature on the breeding biology and physiological condition of Lesser Kestrels and European Rollers chicks and to provide recommendations for management adaptation in the face of predicted global warming. The microclimate of the nest played a key role in physiological and growth of offspring of both species. In the last decade, the provisioning of artificial nest-sites in the study area lead to an increase in the breeding populations of kestrels and rollers. However, this study demonstrated that provided wooden nest-boxes reach very high temperatures that affect chick survival of lesser kestrels and chick growth of both species. The study also showed that high temperatures inside the nest impacted the physiological response to stress in lesser kestrel chicks, as measured by the heterophil/lymphocyte (H/L) ratios. The impact of high temperatures on lesser kestrels and rollers highlight a need for actions to modify and adapt conservation efforts and future planning to account for climate change. In the future, wooden-nest boxes should be avoided and new materials should be tested to reduce inside temperatures