Association mapping of seed quality traits using the Canadian flax (Linum usitatissimum L.) core collection

KEY MESSAGE: The identification of stable QTL for seed quality traits by association mapping of a diverse panel of linseed accessions establishes the foundation for assisted breeding and future fine mapping in linseed. ABSTRACT: Linseed oil is valued for its food and non-food applications. Modifying its oil content and fatty acid (FA) profiles to meet market needs in a timely manner requires clear understanding of their quantitative trait loci (QTL) architectures, which have received little attention to date. Association mapping is an efficient approach to identify QTL in germplasm collections. In this study, we explored the quantitative nature of seed quality traits including oil content (OIL), palmitic acid, stearic acid, oleic acid, linoleic acid (LIO) linolenic acid (LIN) and iodine value in a flax core collection of 390 accessions assayed with 460 microsatellite markers. The core collection was grown in a modified augmented design at two locations over 3 years and phenotypic data for all seven traits were obtained from all six environments. Significant phenotypic diversity and moderate to high heritability for each trait (0.73–0.99) were observed. Most of the candidate QTL were stable as revealed by multivariate analyses. Nine candidate QTL were identified, varying from one for OIL to three for LIO and LIN. Candidate QTL for LIO and LIN co-localized with QTL previously identified in bi-parental populations and some mapped nearby genes known to be involved in the FA biosynthesis pathway. Fifty-eight percent of the QTL alleles were absent (private) in the Canadian cultivars suggesting that the core collection possesses QTL alleles potentially useful to improve seed quality traits. The candidate QTL identified herein will establish the foundation for future marker-assisted breeding in linseed. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00122-014-2264-4) contains supplementary material, which is available to authorized users

Método de reciclaje para rehabilitar pavimentos hidráulicos incrementando su tiempo de servicio

El presente trabajo de investigación tiene como finalidad difundir los Métodos de Reciclaje de los pavimentos hidráulicos en los cuales su principal objetivo es el reciclaje in-situ de la losa de concreto hidráulica en malas condiciones mediante equipos especializados para ser reutilizada como una base granular de alta resistencia. Esta base compuesta de fragmentos de la losa de concreto hidráulica existente tendrá un recubrimiento conformado por una mezcla asfáltica en caliente que aportará a la capacidad estructural del pavimento, resultando en un pavimento de comportamiento semi-flexible, en donde se tendrá la resistencia estructural de un pavimento hidráulico y el alto desempeño funcional de un pavimento flexible. La investigación se centró en evaluar el pavimento hidráulico deteriorado y con múltiples fallas de diversas magnitudes de una vía principal urbana denominada Av. Del Ejército, ubicada en el distrito de Magdalena del Mar – Lima, con el fin de proponer la mejor solución de rehabilitación entre los Métodos de Reciclaje del pavimento hidráulico. Estos métodos fueron comparados con los Métodos Convencionales de rehabilitación más utilizados para pavimentos hidráulicos. Como resultado se determinó que el método a proponer más adecuado para la rehabilitación del pavimento hidráulico existente de la Av. Del Ejército es el Método de Reciclaje “Rubblize” (Fragmentación) con Máquina Rompedora Resonante. Se evaluaron las solicitaciones de cargas de tráfico mediante el programa PerRoad para un tiempo de diseño de 30 años y se diseñó el espesor del recubrimiento de la losa fragmentada empleando una mezcla asfáltica en caliente modificada con polímeros SBS.Tesi

Role of boron and its interaction with other elements in plants

Boron (B) is an essential microelement for plants, and its deficiency can lead to impaired development and function. Around 50% of arable land in the world is acidic, and low pH in the soil solution decreases availability of several essential mineral elements, including B, magnesium (Mg), calcium (Ca), and potassium (K). Plants take up soil B in the form of boric acid (H3BO3) in acidic soil or tetrahydroxy borate [B(OH)4]- at neutral or alkaline pH. Boron can participate directly or indirectly in plant metabolism, including in the synthesis of the cell wall and plasma membrane, in carbohydrate and protein metabolism, and in the formation of ribonucleic acid (RNA). In addition, B interacts with other nutrients such as Ca, nitrogen (N), phosphorus (P), K, and zinc (Zn). In this review, we discuss the mechanisms of B uptake, absorption, and accumulation and its interactions with other elements, and how it contributes to the adaptation of plants to different environmental conditions. We also discuss potential B-mediated networks at the physiological and molecular levels involved in plant growth and development

Characterization of novel genic SSR markers in Linum usitatissimum (L.) and their transferability across eleven Linum species

Little is known about the evolutionary relationships among Linum species, basically because of the lack of transferable molecular markers. Currently, expressed sequence tags available in public databases provide an opportunity for the rapid and inexpensive development of simple sequence repeat (SSR) markers in wild flax species. In this regard, fifty expressed sequence tag-derived microsatellite markers (EST-SSRs) were evaluated for polymorphism and transferability in 50 Linum usitatissimum cultivars/accessions and 11 Linum species. Among them 23 EST-SSRs were polymorphic in L. usitatissimum, while 2-4 alleles were detected (average 2.26 per locus). The polymorphism information content value ranged from 0.08 to 0.55 (average 0.38). Forty one genic markers (95.3%) produced strong amplicons in at least two of the 11 Linum species. The percentage of cross amplification ranged from 34.1% to 92.7% in L. tauricum and L. bienne, respectively. Moreover, the rate of transferability was associated positively with the botanical section. Our results suggest that the high degree of EST-SSRs transferability to Linum species can be a useful enhancement of the current database of SSR markers for future genetic and evolutionary studies

Aislamiento e Identificación Molecular de Levaduras Autóctonas en Viñedo de la Variedad Malvasía Blanca

Se realizó el aislamiento e identificación de levaduras nativas de un viñedo de la especie Vitis vinifera variedad Malvasía blanca, en la Región Zuliana. Se muestrearon aséptica y aleatoriamente bayas y partes de la planta (hojas, raquis, corteza y suelo), de un total de 123 plantas, correspondientes a un viñedo de la variedad de uva Malvasía. A aproximadamente a 500m del viñedo, se encuentra la bodega. La identificación de las levaduras aisladas en el viñedo se realizó por técnicas moleculares mediante PCR-RFLP, sometiendo los productos amplificados a un análisis de restricción con las enzimas Hinf I, Hae III, CfoI y DdeI.  La distribución de las levaduras en los diversos sustratos fue en el suelo 60% Hanseniaspora guillermondii y 40% Hanseniaspora uvarum, en la corteza 90% Candida sake y 10% Hanseniaspora uvarum, en hojas 100% por Rhodotorula mucilagenosa, en raquis 100% por Aureobasidium pullulans y en las bayas 96% Rhodotorula mucilagenosa y 4% Aureobasidium pullulans.  En el viñedo están ampliamente difundidos los géneros Ascomycetos Hanseniaspora, Candida y Aureobasidium y el género Basdiomycetos Rhodotorula, siendo las levaduras oxidativas Aureobasidium y Rhodotorula las de mayor difusión en el mismo, sin embargo, cabe destacar la presencia de levaduras fermentativas como los géneros Hanseniaspora y Candida, importantes levaduras con reconocido potencial enológico, que podrán ser utilizadas en futuras fermentaciones alcohólicas para obtener vinos con calidad única por ser fermentados con levaduras autóctonas adaptadas a clima tropical.  Palabras clave: levaduras autóctonas, variedad Malvasía, PCR-RFLP 5,8S.    ABSTRACT The isolation and identification of native yeasts from a vineyard of the Vitis vinifera white variety Malvasia was carried out in Zulia, Venezuela. Aseptically and randomly, berries and parts of the plant (leaves, rachis, bark and soil) were sampled from a total of 123 plants, corresponding to a vineyard of the Malvasia grape variety. A winery is located at approximately 500 m from the vineyard. The identification of the yeasts isolated in the vineyard was carried out by molecular techniques by PCR-RFLP, subjecting the amplified products to a restriction analysis with the enzymes Hinf I, Hae III, CfoI and DdeI. The distribution of the yeasts in the different substrates was in the soil 60% Hanseniaspora guillermondii and 40% Hanseniaspora uvarum, in the bark 90% Candida sake and 10% Hanseniaspora uvarum, in leaves 100% by Rhodotorula mucilagenosa, in rachis 100% by Aureobasidium pullulans and in berries 96% Rhodotorula mucilagenosa and 4% Aureobasidium pullulans. In the vineyard, the Ascomycetos type Hanseniaspora, Candida and Aureobasidium and the genus Basdiomycetos Rhodotorula are widely spread, with the oxidative yeasts Aureobasidium and Rhodotorula being the most widespread, however, the presence of fermentative yeasts such as the Hanseniaspora  and Candida genera, important yeasts with recognized oenological potential, which can be used in future alcoholic fermentations to obtain wines with unique quality by being fermented with native yeasts adapted to tropical climate. Key words: native yeasts, Malvasía variety, PCR-RFLP 5.8S

Molecular, genetic and transcriptional evidence for a role of VvAGL11 in stenospermocarpic seedlessness in grapevine

<p>Abstract</p> <p>Background</p> <p>Stenospermocarpy is a mechanism through which certain genotypes of <it>Vitis vinifera </it>L. such as Sultanina produce berries with seeds reduced in size. Stenospermocarpy has not yet been characterized at the molecular level.</p> <p>Results</p> <p>Genetic and physical maps were integrated with the public genomic sequence of <it>Vitis vinifera </it>L. to improve QTL analysis for seedlessness and berry size in experimental progeny derived from a cross of two seedless genotypes. Major QTLs co-positioning for both traits on chromosome 18 defined a 92-kb confidence interval. Functional information from model species including <it>Vitis </it>suggested that <it>VvAGL11</it>, included in this confidence interval, might be the main positional candidate gene responsible for seed and berry development.</p> <p>Characterization of <it>VvAGL11 </it>at the sequence level in the experimental progeny identified several SNPs and INDELs in both regulatory and coding regions. In association analyses performed over three seasons, these SNPs and INDELs explained up to 78% and 44% of the phenotypic variation in seed and berry weight, respectively. Moreover, genetic experiments indicated that the regulatory region has a larger effect on the phenotype than the coding region. Transcriptional analysis lent additional support to the putative role of <it>VvAGL11's </it>regulatory region, as its expression is abolished in seedless genotypes at key stages of seed development. These results transform <it>VvAGL11 </it>into a functional candidate gene for further analyses based on genetic transformation.</p> <p>For breeding purposes, intragenic markers were tested individually for marker assisted selection, and the best markers were those closest to the transcription start site.</p> <p>Conclusion</p> <p>We propose that <it>VvAGL11 </it>is the major functional candidate gene for seedlessness, and we provide experimental evidence suggesting that the seedless phenotype might be caused by variations in its promoter region. Current knowledge of the function of its orthologous genes, its expression profile in <it>Vitis </it>varieties and the strong association between its sequence variation and the degree of seedlessness together indicate that the D-lineage MADS-box gene <it>VvAGL11 </it>corresponds to the <it>Seed Development Inhibitor locus </it>described earlier as a major locus for seedlessness. These results provide new hypotheses for further investigations of the molecular mechanisms involved in seed and berry development.</p

Mapping aluminum tolerance loci in cereals: A tool available for crop breeding

Aluminum (Al) toxicity is the main factor limiting crop productivity in acidic soils around the world. In cereals, this problem reduces crop yields by 30-40%. The use of DNA-based markers linked to phenotypic traits is an interesting alternative approach. Strategies such as molecular marker-assisted selection (MAS) in conjunction with bioinformatics-based tools such as graphical genotypes (GGT) have been important for confirming introgression of genes or genomic regions in cereals but also to reduce the time and cost of identifying them through genetic selection. These biotechnologies also make it possible to identify target genes or quantitative trait loci (QTL) that can be potentially used in similar crops to increase their productivity. This review presents the main advances in the genetic improvement of cereals for Al-tolerance

Búsqueda de mutaciones en los genes katG, inhA y ahpC y su relación con resistencia a isoniacida en el Complejo Mycobacterium tuberculosis

Tesis (Maestría en Ciencias en Biotecnología Genómica), Instituto Politécnico Nacional, CBG, 2014, 1 archivo PDF, (121 páginas). tesis.ipn.m

Entre el olvido y la memoria: Tenerife

instalacion-videoEn Tenerife Valle del Cauca, el conflicto armado generó cambios importantes en una población dedicada puntualmente a la agricultura, no por nada es conocida como la despensa del Valle del Cauca y por efectos de enfrentamientos, extorsiones, desaparicionesIn Tenerife Valle del Cauca, the armed conflict generated important changes in a population dedicated to agriculture, not for nothing is known as the Valle del Cauca pantry and due to the effects of confrontations, extortion, disappearances and deaths, a