Integración de marcadores microsatélites en el mapa ultradenso de solanum tuberosum y su comparación con el de solanum phureja

La papa, es el cultivo no cereal más importante del mundo con una producción mundial que ha alcanzado los 329 millones de toneladas anuales. A pesar de la enorme importancia de este cultivo, aún se desconocen aspectos sobre la genética de muchas de sus características cualitativas y cuantitativas. El mapa UHD (> 10 000 AFLPs) de Solanum tuberosum, ha sido una herramienta de gran utilidad para el proyecto de secuenciamiento del genoma de la papa, que se enfocó inicialmente en el individuo RH89-039-16. Sin embargo, debido a su heterocigocidad se optó por una línea doble monohaploide de la especie S. phureja (DM1-3516R44), para lo cual fue necesario la construcción de novo de un mapa genético. Con la finalidad de identificar cambios en la estructura genómica de estos dos individuos, se analizaron 74 marcadores microsatélites cartografiados previamente en DM1-3516R44, lográndose integrar 62 loci microsatélite en el mapa UHD de RH89-039-16. La comparación de los mapas genéticos de RH89-039-16 y DM1-3516R44 reveló la existencia de colinealidad en grandes fragmentos de los cromosomas II, V y VI, mientras que los cromosomas I, IV, X y XII presentan diferencias en cuanto al contenido de ciertos marcadores. Los cromosomas VII y IX muestran la presencia de rearreglos cromosómicos que podrían ser inversiones o translocaciones, además la presencia de loci duplicados en los cromosomas VIII, I y II, indicaría la ocurrencia de eventos de duplicación intra e intercromosómica. Sin embargo para verificar tales cambios es necesario cartografiar más microsatélites y saturar la zona cromosómica de interés. -- Palabras clave: Papa, marcador molecular, microsatélite, cartografía genética, mapa UHD, colinealidad.-- Potato is the most important non-grain food crop in the world, with production in 2009 reaching 330 million tons. Despite the importance of the potato in the world, the genetics of many important qualitative and quantitative agronomic traits are poorly understood. The UHD map (>10 000 AFLP markers) of Solanum tuberosum, was a great tool for the Potato Genome Sequencing Project (clon RH89-039-16). However due to the high heterozygosity of RH89-039-16, it was decided to sequence the S.phureja doubled monoploid clone, DM1-3 516R44, for which it was necessary the de novo construction of a genetic map. Microsatellites markers mapped in DM was mapped in the UHD map, with two purposes, integrate microsatellites in the UHD map, and identify changes in the chromosomal organization of Solanum tuberosum (RH89-039-16) and Solanum phureja (DM1-3516R44), by comparison of their genetic maps. The aligment of microsatellites of RH89-039-16 and DM1-3516R44 maps along chromosomes has shown the existence of collinearity in the chromosomes II, V and VI, while the chromosomes I, IV, X and XII has shown differences in content of some markers. The chromosomes VII y IX has shown the presence of chromosomal rearrangements that could be inversions or translocations, further the presence of duplicated loci in chromosomes VIII, I and II might indicate that of intra- and interchromosomal duplications have occurred. However in order to verify these alterations would be necessary mapping more microsatellite markers and saturate the chromosomal region of interest. -- Key words: potato, molecular marker, microsatellite, genetic mapping, UHD map, collinearityTesi

The molecular dialog between oomycete effectors and their plant and animal hosts

Funding Information: This work was supported by European Union's HORIZON 2020 Research programme under the Grant Agreement no. 766048 “PROTECTA”, University of Aberdeen (PvW), Wageningen University and Research (VGAAV) , the BBSRC [ BB/P020224/1 , BB/M026566/1 (MS, PvW)], Newton Fund GRP Aquaculture [ BB/N005058/1 (PvW)], and the Peruvian Council for science, technology and technological innovation (CONCYTEC) FONDECYT contract 129–2017 .Peer reviewedPublisher PD

Transcriptoma de la respuesta a la sequía en Solanum tuberosum subsp. Andigena

El reciente desarrollo del RNA-Seq, un método de secuenciamiento masivo en paralelo para el análisis de transcriptomas permite conocer el perfil de expresión de las plantas en respuesta a estrés de tipo abiótico y biótico. En este estudio, se secuenció el mRNA proveniente de hojas y raíces de dos variedades de Solanum tuberosum subsp. andigena, una tolerante y otra susceptible, expuestas a diferentes niveles de sequía. Lecturas de 50 pares de bases provenientes de mRNA, se mapearon al genoma de papa: entre el 75 - 82% mapearon a posiciones únicas, 6 - 14% mapearon a múltiples posiciones y 9 - 12% no mapearon a posición alguna del genoma. Comparando los perfiles de expresión, se encontraron entre 887 a 1925 genes inducidos/reprimidos por sequía en la variedad susceptible y 998- 1995 en la tolerante. Se anotaron funcionalmente los 200 genes más inducidos por cada tratamiento encontrándose información primaria respecto a los procesos biológicos y moleculares involucrados durante la sequía. Finalmente, fue posible correlacionar los perfiles de expresión diferencial de los genes durante la sequía, formándose 31 módulos con aquellos genes altamente correlacionados. Este estudio generó información de gran valor que podrá ser utilizada en futuros estudios para comprender mejor los mecanismos moleculares de tolerancia a sequía en papa y especies cercanas.Fondo Nacional de Desarrollo Científico y Tecnológico - Fondecy

Identification of Solanum Immune Receptors by Bulked Segregant RNA-Seq and High-Throughput Recombinant Screening

The identification, understanding, and deployment of immune receptors are crucial to achieve high-level and durable resistance for crops against pathogens. In potato, many R genes have been identified using map-based cloning strategies. However, this is a challenging and laborious task that involves the development of a high number of molecular markers for the initial mapping, and the screening of thousands of plants for fine mapping. Bulked segregant RNA-Seq (BSR-Seq) has proven to be an efficient technique for the mapping of resistance genes. The RNA from two bulks of plants with contrasting phenotypes is sequenced and analyzed to identify single-nucleotide polymorphism (SNPs) markers linked to the target gene. Subsequently, the SNP markers that are identified can be used to delimit the mapping interval. Additionally, we designed an in vitro recombinant screening strategy that is advantageous for analyzing a large number of plants, in terms of time, space, and cost. Tips and detailed protocols, including BSR-Seq, bioinformatic analysis, and recombinant screening, are provided in this chapter

Transcriptome profiling shows a rapid variety-specific response in two Andigenum potato varieties under drought stress

Potato is a drought-sensitive crop whose global sustainable production is threatened by alterations in water availability. Whilst ancestral Solanum tuberosum Andigenum landraces retain wild drought tolerance mechanisms, their molecular bases remain poorly understood. In this study, an aeroponic growth system was established to investigate stress responses in leaf and root of two Andigenum varieties with contrasting drought tolerance. Comparative transcriptome analysis revealed widespread differences in the response of the two varieties at early and late time points of exposure to drought stress and in the recovery after rewatering. Major differences in the response of the two varieties occurred at the early time point, suggesting the speed of response is crucial. In the leaves and roots of the tolerant variety, we observed rapid upregulation of ABA-related genes, which did not occur until later in the susceptible variety and indicated not only more effective ABA synthesis and mobilization, but more effective feedback regulation to limit detrimental effects of too much ABA. Roots of both varieties showed differential expression of genes involved in cell wall reinforcement and remodeling to maintain cell wall strength, hydration and growth under drought stress, including genes involved in lignification and wall expansion, though the response was stronger in the tolerant variety. Such changes in leaf and root may help to limit water losses in the tolerant variety, while limiting the reduction in photosynthetic rate. These findings provide insights into molecular bases of drought tolerance mechanisms and pave the way for their reintroduction into modern cultivars with improved resistance to drought stress and yield stability under drought conditions

The molecular dialog between oomycete effectors and their plant and animal hosts

Oomycetes form a phylogenetically distinct group of eukaryotic microorganisms that include some of the most notorious pathogens of plants and animals. Through the deployment of a remarkably diverse array of effector proteins, oomycete pathogens succeed to overcome host defences and cause infection. Effectors can operate extracellularly or enter living cells where they target diverse subcellular compartments. Genome sequence information indicates that oomycetes express several hundred host-translocating effectors potentially targeting a myriad of host processes. To counteract, plants rely on a wide variety of extra- and intracellular immune receptors facilitating pattern-triggered and effector-triggered immunity, respectively. Similarly, effectors from animal pathogenic oomycetes also target host immune response pathways, which in turn causes the activation of the humoral and adaptive immune system. In this review, we compare plant and animal pathogenic oomycete effectors regarding their type, function, genetic diversity, as well as host responses

Recognition of Pep-13/25 MAMPs of Phytophthora localizes to an RLK locus in Solanum microdontum

Pattern-triggered immunity (PTI) in plants is mediated by cell surface-localized pattern recognition receptors (PRRs) upon perception of microbe-associated molecular pattern (MAMPs). MAMPs are conserved molecules across microbe species, or even kingdoms, and PRRs can confer broad-spectrum disease resistance. Pep-13/25 are well-characterized MAMPs in Phytophthora species, which are renowned devastating oomycete pathogens of potato and other plants, and for which genetic resistance is highly wanted. Pep-13/25 are derived from a 42 kDa transglutaminase GP42, but their cognate PRR has remained unknown. Here, we genetically mapped a novel surface immune receptor that recognizes Pep-25. By using effectoromics screening, we characterized the recognition spectrum of Pep-13/25 in diverse Solanaceae species. Response to Pep-13/25 was predominantly found in potato and related wild tuber-bearing Solanum species. Bulk-segregant RNA sequencing (BSR-Seq) and genetic mapping the response to Pep-25 led to a 0.081 cM region on the top of chromosome 3 in the wild potato species Solanum microdontum subsp. gigantophyllum. Some BAC clones in this region were isolated and sequenced, and we found the Pep-25 receptor locates in a complex receptor-like kinase (RLK) locus. This study is an important step toward the identification of the Pep-13/25 receptor, which can potentially lead to broad application in potato and various other hosts of Phytophthora species

Construction of reference chromosome-scale pseudomolecules for potato:integrating the potato genome with genetic and physical maps

Artículo de publicación ISIThe genome of potato, a major global food crop, was recently sequenced. The work presented here details the integration of the potato reference genome (DM) with a new sequence-tagged site marker2based linkage map and other physical and genetic maps of potato and the closely related species tomato. Primary anchoring of the DM genome assembly was accomplished by the use of a diploid segregating population, which was genotyped with several types of molecular genetic markers to construct a new ~936 cM linkage map comprising 2469 marker loci. In silico anchoring approaches used genetic and physical maps from the diploid potato genotype RH89-039-16 (RH) and tomato. This combined approach has allowed 951 superscaffolds to be ordered into pseudomolecules corresponding to the 12 potato chromosomes. These pseudomolecules represent 674 Mb (~93%) of the 723 Mb genome assembly and 37,482 (~96%) of the 39,031 predicted genes. The superscaffold order and orientation within the pseudomolecules are closely collinear with independently constructed high density linkage maps. Comparisons between marker distribution and physical location reveal regions of greater and lesser recombination, as well as regions exhibiting significant segregation distortion. The work presented here has led to a greatly improved ordering of the potato reference genome superscaffolds into chromosomal “pseudomolecules”