Key messageSNPs in candidate genesPain-1,InvCD141(invertases),SSIV(starch synthase),StCDF1(transcription factor),LapN(leucine aminopeptidase), and cytoplasm type are associated with potato tuber yield, starch content and/or starch yield.AbstractTuber yield (TY), starch content (TSC), and starch yield (TSY) are complex characters of high importance for the potato crop in general and for industrial starch production in particular. DNA markers associated with superior alleles of genes that control the natural variation of TY, TSC, and TSY could increase precision and speed of breeding new cultivars optimized for potato starch production. Diagnostic DNA markers are identified by association mapping in populations of tetraploid potato varieties and advanced breeding clones. A novel association mapping population of 282 genotypes including varieties, breeding clones and Andean landraces was assembled and field evaluated in Northern Spain for TY, TSC, TSY, tuber number (TN) and tuber weight (TW). The landraces had lower mean values of TY, TW, TN, and TSY. The population was genotyped for 183 microsatellite alleles, 221 single nucleotide polymorphisms (SNPs) in fourteen candidate genes and eight known diagnostic markers for TSC and TSY. Association test statistics including kinship and population structure reproduced five known marker–trait associations of candidate genes and discovered new ones, particularly for tuber yield and starch yield. The inclusion of landraces increased the number of detected marker–trait associations. Integration of the present association mapping results with previous QTL linkage mapping studies for TY, TSC, TSY, TW, TN, and tuberization revealed some hot spots of QTL for these traits in the potato genome. The genomic positions of markers linked or associated with QTL for complex tuber traits suggest high multiplicity and genome wide distribution of the underlying genes.Electronic supplementary materialThe online version of this article (doi:10.1007/s00122-016-2665-7) contains supplementary material, which is available to authorized users.

Red band needle blight caused by Dothistroma septosporum and D. pini, and brown spot needle blight caused by Lecanosticta acicola provoke severe and premature defoliation in Pinus, and subsequent reduction of photosynthetic surfaces, vitality, and growth in young and adult trees. The recurrent damage results in branch and tree death. Until recently, pine needle blight diseases have had only minor impacts on native and exotic forest trees in the North of Spain, but in the past five years, these pathogen species have spread widely and caused severe defoliation and mortality in exotic and native plantations of Pinus in locations where they were not detected before. In an attempt to understand the main causes of this outbreak and to define the effectiveness of owners' management strategies, four research actions were implemented: a survey of the management activities implemented by the owners to reduce disease impact, the evaluation of specific symptoms and damage associated with infection, and the identification of the causative pathogenic species and their reproductive capacity. Morphological characteristics of the fungus and molecular identification were consistent with those of Lecanosticta acicola and Dothistroma spp., D. septosporum, D. Pini, and both mating types were present for the three identified pathogens. The local silvicultural management performed, mainly pruning and thinning, was not resulting in the expected improvement. The results of this study can be applied to establish guidelines for monitoring and controlling the spread of needle blight pathogens.

Based on an F(1) progeny of 73 individuals, two parental maps were constructed according to the double pseudo-test cross strategy. The paternal map contained 16 linkage groups for a total genetic length of 1,792 cM. The maternal map covered 1,920 cM, and consisted of 12 linkage groups. These parental maps were then integrated using 66 intercross markers. The resulting consensus map covered 2,035 cM and included 755 markers (661 AFLPs, 74 SSRs, 18 ESTPs, the 5S rDNA and the early cone formation trait) on 12 linkage groups, reflecting the haploid number of chromosomes of Picea abies. The average spacing between two adjacent markers was 2.6 cM. The presence of 39 of the SSR and/or ESTP markers from this consensus map on other published maps of different Picea and Pinus species allowed us to establish partial linkage group homologies across three P. abies maps (up to five common markers per linkage group). This first saturated linkage map of P. abies could be therefore used as a support for developing comparative genome mapping in conifers.

Background: Pollutants and other stressing factors like mold infection might increase the production of pathogen-related proteins in plants. Since this is invoked as one of the causes for the high prevalence of allergic diseases in developed countries, we aimed to determine the potential effect of environmental pollution, with or without mold infection of the trees, on the allergenic potency of pine pollen (Pinus radiata). Methods: Pine pollen samples were recovered from three selected areas: low polluted (A), highly polluted (B) and highly polluted and infected with fungi (Spheropsis sapinea) (C). The allergenic potency of pollen from areas A, B or C were compared in vivo in 35 pine pollen-allergic patients by skin prick test and specific IgE (sIgE) quantification. Pollen was also analyzed in vitro by SDS-PAGE immunoblotting, RAST inhibition and cDNA-AFLP (amplified fragment length polymorphism) to compare differences in proteins and mRNA expression. Results: The allergenic potency measured by prick test, sIgE and RAST inhibition was greater in pollen A, which was exposed to smaller amounts of NO_x, PM₁₀ and SO₂ but greater amounts of O₃. No differences were found in IgE-binding bands in immunoblotting or densitometry of the bands. In cDNA-AFLP, three homologous transcript-derived fragments were expressed in samples B only, with an expressed sequence tag related with stress-regulated gene expression. Conclusions: A greater allergenic potency, in terms of skin tests and sIgE, is observed in pine pollen coming from unpolluted areas. We consider that this fact might be related to a higher exposure to ozone, resulting in a greater expression of allergenic proteins.

-A series of micrografting conditions using needle fascicles from trees of different ages as scions have been evaluated for Pinus radiata D. Don. to increase success of in vitro propagation. Micrografting success depended on the quality of the graft process as well as age, location and development stage of the scion and tree age. 11-month-old scions, taken in January from terminal portions of basal branches show the best micrografting-induced response. Responsiveness of scions decreases with the donor tree age, although this could be overcome by optimising micrografting conditions. reinvigoration / micrografting / maturation / vegetative propagation / Pinus radiata / in vitro culture Résumé -Facteurs impliqués dans le micro-greffage de Pinus radiata D. Don. Différentes conditions de micro-greffage, utilisant comme greffons des brachyblastes provenant d'arbres d'âges différents, ont été comparées afin d'évaluer les possibilités d'améliorer la propagation in vitro de Pinus radiata. Le succès du micro-greffage dépend tout autant de la qualité du processus de greffage que de l'âge, de la localisation et du stade de développement du greffon, ou que de l'âge de l'arbre. Des greffons de 11 mois prélevés en janvier sur la portion terminale de branches de la base de l'arbre donnent les meilleures réponses au micro-greffage. Cette réponse diminue avec l'âge de l'arbre sur lequel ils sont prélevés, bien que ceci puisse en partie être surmonté en optimisant les conditions du micro-greffage.vigueur / micro-greffage / maturation / multiplication végétative / Pinus radiata / culture in vitro Abbreviations BA: benzyladenine IBA: indolebutyric acid MS: Murashige and Skoog culture medium NAA: naphtalenacetic acid QL: Quoirin and Lepoivre culture medium QLP: elongation culture medium QLS1: stimulation culture medium QLY: high proliferation culture medium QL1: proliferation culture medium.

The existence of a latent stage within host tissue of the pine pathogens Fusarium circinatum and Diplodia sapinea, the causal agents of pitch canker and shoot blight disease respectively, has previously been cited. However, studies on this cryptic phase in each disease lifecycle has only been focused on the host aerial parts but not on the roots. Therefore, our objective was to analyze the presence of both pathogens in roots of non-symptomatic mature trees in plantations where the pathogens are known to be causing canker symptoms. For that, we sampled roots from ten non-symptomatic and ten symptomatic trees in three Pinus radiata and one Pinus pinaster plantations in Basque Country, Spain. Both pathogens were isolated from roots of non-symptomatic trees in a higher frequency than from roots of symptomatic trees, 23.3% and 6.6% respectively for D. sapinea and 16.6% and 3.3% respectively for F. circinatum. Neither pathogens was detected in the P. pinaster plantation. The two pathogens were never isolated from the same tree. A high molecular variability was observed for D. sapinea isolates with six different haplotypes and two mating types for the eleven characterized isolates, but only one haplotype and mating type was found for F. circinatum, with all isolates of both fungi being proved pathogenic. These results evidence the importance root infection may have in the disease lifecycle and, therefore, disease management.

-Two parental linkage maps have been constructed from the P. pinaster reference population (0024 × C803) based on AFLP, SSR and EST markers. Although segregating polymorphism was low due to a high degree of homozygosity in the parents, 12 linkage groups with 26 to 46 markers each were obtained for each parent. The availibility of 70 anchor points based on fragments common to both parents and based on codominant SSR and EST markers allowed to determine homologous chromosomes for both maps and to construct one integrated map. Total genome length of the integrated map is around 2000 cM including 1182 markers. Since some of the EST and SSR markers are also mapped in different pine species, association of linkage groups of our reference population with those of other published maps was possible.

No abstract