R. Zas

• PhD in Forestry
• Researcher at Spanish National Research Council

Key message The effects of MJ on pine trees are species-specific and trigger a resistant phenotype to the PWN. A more dynamic response of hormones and gene expression in Pinus pinea explains the high resistance to Bursaphelenchus xylophilus of this species. Abstract Knowledge on hormonal and genetic mechanisms of pine trees in response to the pine...

Maritime pine (Pinus pinaster Ait.) covers vast areas and is of economic importance in southwestern Europe, particularly in Galicia (NW Spain). Galicia is a heterogeneous region with an Atlantic climate in the coast and a Mediterranean-like climate in the inland, where forest reproductive materials (FRM) with proper adaptation, productivity and tim...

Pine resin is a valuable non-wood forest product with an increasing interest in multiple industrial sectors. Resin-tapping activities also provide valuable ecosystem services in timber-oriented and highly productive pine forest of Atlantic regions, where little previous experience in resin-tapping is available. The objectives of this study were to...

Purpose of Review In this review, we synthesise current knowledge on trade-offs among traits in key fitness dimensions and identify major research gaps with the intention of laying the groundwork for a rapid advance in tree breeding for multiple objectives as a key contribution to the sustainability of planted forests in the future. Recent Finding...

Purpose of Review. In this review, we synthesize current knowledge on trade-offs among traits in key fitness dimensions and identify major research gaps with the intention of laying the groundwork for a rapid advance in tree breeding for multiple objectives as a key contribution to the sustainability of planted forests in the future. Recent Finding...

The contribution of genetic adaptation and plasticity to intraspecific phenotypic variability remains insufficiently studied in long‐lived plants, as well as the relevance of neutral versus adaptive processes determining such divergence. We examined the importance of phylogeographic structure and climate in modulating genetic and plastic changes an...

Phenotypic plasticity is a main mechanism for sessile organisms to cope with changing environments. Plasticity is genetically based and can evolve under natural selection so that populations within a species show distinct phenotypic responses to environment. An important question that remains elusive is whether the intraspecific variation in plasti...

Buscando dar respuesta a la inquietud existente sobre la com-patibilidad de la producción de madera y resina en los pinares atlánticos, dentro del proyecto ACREMA hemos analizado el efecto de la resinación durante varios años seguidos sobre la calidad de la madera y sobre el crecimiento, la reproducción y la sanidad de los árboles. Los resultados s...

Selecting the best resin tapping method and stimulant paste in the resin tapping process is crucial. In timber-oriented rainy Atlantic pine forests of north-west Spain, the interest in resin tapping is raising but information on the best tapping methods and pastes is still lacking. In this study, an appropriate experimental design used on five repr...

Selecting the best resin tapping method and stimulant paste in the resin tapping process is crucial. In timber-oriented rainy Atlantic pine forests of north-west Spain, the interest in resin tapping is raising but information on the best tapping methods and pastes is still lacking. In this study, an appropriate experimental design used on five repr...

Mycorrhizal fungi can help plants to cope with drought, but research on the fungal communities that are more resistant to drought or alleviate drought stress of trees is still scarce. In this study, we investigated effects of drought on soil fungal communities and explored potential fungal traits related to drought resistance under greenhouse condi...

Phenotypic plasticity is a main mechanism for organisms to cope with changing environments and broaden their ecological range. Plasticity is genetically based and can evolve under natural selection, such that populations within a species show distinct phenotypic responses to the environment if evolved under different conditions. Understanding how i...

Induced defences in conifers are an effective strategy that allows individuals to increase resistance against pests and pathogens by optimizing associated costs. Studies exploring inducibility of defences in conifers have usually been conducted in young individuals (i.e., seedlings and saplings) whereby effects were addressed within weeks or months...

La resina producida por los pinos es un recurso renovable con múltiples aplicaciones industriales, lo que ha generado un creciente interés en este producto forestal. La extracción de resina emerge como una actividad económica complementaria a la producción maderera que puede contribuir significativamente a la fijación de población rural y a evitar...

The advent of the next-generation genome sequencing technologies has allowed approaching the sequencing and analysis of large and complex conifer genomes. Maritime pine (Pinus pinaster Ait.) is an economically and ecologically important conifer species widely distributed in South-West Europe, which shows a significant genetic and adaptive variabili...

Although the straightening capacity of the stem is key for light capture and mechanical stability in forest trees, little is known about its adaptive implications. Assuming that stem straightening is costly, trade-offs are expected with competing processes such as growth, maintenance and defences. We established a manipulative experiment in a commo...

As massive, sessile and long-lived organisms, Mediterranean pines are exposed to a wide array of insect herbivores that feed on their tissues causing damage and ultimately, tree death. To protect themselves against biotic risks, pines have a complex battery of chemical and physical defenses, that act directly to kill or repel the antagonist organis...

To counteract the effects of herbivores and pathogens, conifers have developed a sophisticated resin-based defensive system. Since defences are costly, trees must continuously accommodate defensive investment through plastic responses to environmental stimuli. However, the extent of such responses can differ at the intra-specific level (i.e. geneti...

Key message Exogenous MJ does not alter the resin duct structure of pines in the cortex, but increases the number, density and mean size of resin ducts in the secondary xylem, particularly in Pinus sylvestris and P. radiata. Abstract Methyl jasmonate (MJ) is an organic compound capable of modulating defence responses in plants. Exogenous applicati...

The potential of pine resin as a renewable non-timber product is furthering the socioeconomic relevance of the resin industry in Europe, where maritime pine (Pinus pinaster Ait.) is the main tapped species. Characterizing maritime pine genetic resources in terms of resin yield potential and its covariation with tree growth is crucial to implement e...

Premise: Persistence of tree populations in the face of global change relies on their capacity to respond to biotic and abiotic stressors through plastic or adaptive changes. Genetic adaptation will depend on the additive genetic variation within populations and the heritability of traits related to stress tolerance. Because traits can be genetica...

El conocimiento de las interacciones árbol-antagonista abarca desde la identificación de los mecanismos defensivos de los árboles hasta las relaciones con otros organismos del ecosistema que puedan condicionar el estado sanitario de las masas forestales. Aquí presentamos los principales avances llevados a cabo por la comunidad científica en el comp...

Pine resin is a highly valuable and sought-after non-timber forest product with multiple uses in many industrial sectors. Maritime pine (Pinus pinaster Ait.) is the main tapped species in Europe, where resin tapping activities are concentrated in only a few specific Mediterranean regions. Although maritime pine also occupies vast extensions under A...

La vecería es el fenómeno por el cual ciertas especies de árboles alternan años de fuerte producción de flores, frutos o semillas con años de poca o ninguna. Un aspecto principal es que se trata de un fenómeno poblacional causado por la floración y fructificación sincronizadas de todos o la mayor parte de los individuos de una masa forestal. La alt...

Pine trees produce large amounts of oleoresin to defend against biotic threats. Resin is highly costly to produce and investment in its production must be accurately optimized in relation to allocation to other life functions such growth. As a result of these costs, resin production is highly variable both genetically (among and within species) and...

Quantifying intraspecific genetic variation and phenotypic plasticity of traits involved in drought tolerance is essential to forecast forest tree vulnerability to climate change. Tree ring analysis was applied to retrospectively assess the resistance, recovery and resilience of a Mediterranean pine in the face of extreme climate episodes. We combi...

Insect outbreaks of increasing frequency and severity in forests are predicted due to climate change. Insect herbivory is known to promote physiological changes in forest trees. However, little is known about whether these plant phenotypic adjustments have cascading effects on tree microbial symbionts such as fungi in roots and foliage. We studied...

The adaptive potential and genetic background of tree species will determine their performance and vitality under changing climate conditions. How environment and genotype influence secondary growth and their climate sensitivity in boreal and temperate conifers has been fairly studied. Provenance studies assessing the genetic variation in plasticit...

Intraspecific variation in plant defences is expected to be the result of adaptive and plastic responses to environmental conditions, where trade-offs between growth and defences are thought to play a key role shaping phenotypic patterns in defensive investment. Axial resin ducts are costly defensive structures that remain imprinted in the tree rin...

The resource availability hypothesis (RAH) was formulated to disentangle patterns of variation among species in plant antiherbivore defences. A novel theoretical framework was recently proposed to expand the RAH among populations within species (RAHintra), but unresolved conceptual issues and considerable gaps surrounding the new hypothesis still n...

Many ecologically important forest trees from dry areas have been insufficiently investigated for their ability to adapt to the challenges posed by climate change, which hampers the implementation of mitigation policies. We analyzed 14 common‐garden experiments across the Mediterranean which studied the widespread thermophilic conifer Pinus halepen...

Conifers have evolved different chemical and anatomical defenses against a wide range of antagonists. Resin ducts produce, store and translocate oleoresin, a complex terpenoid mixture that acts as both a physical and a chemical defense. Although resin duct characteristics (e.g., number, density, area) have been positively related to biotic resistan...

Inducibility of defences in response to biotic stimuli is considered an important trait in plant resistance. In conifers, previous research has mostly focused on the inducibility of the volatile fraction of the oleoresin (mono- and sesquiterpenes), leaving the inducibility of the non-volatile resin acids largely unexplored, particularly in response...

Resin ducts are important anatomical defensive traits related to biotic resistance in conifers. Previous studies have reported intraspecific genetic variation in resin duct characteristics. However, little is currently known about the micro-evolutionary patterns and adaptive value of these defensive structures. Here, we quantified inter-population...

El gorgojo del pino (Hylobius abietis) es una de las plagas más devastadoras en las plantaciones de coníferas en el norte y centro de Europa. Aunque también está presente y es potencialmente dañino en el sur de Europa, se ha prestado poca atención a esta plaga en esa región. Con el objetivo de cuantificar el riesgo potencial del gorgojo como plaga...

Breeding for resistance to forest pests and pathogens is emerging as a promising tool for minimising the impact of the increasing biotic threats that our forests are experiencing as a consequence of global change. Efficient phenotyping protocols of resistance are urgently needed. Here we present the results of two experiments aimed to determine whe...

The pine weevil (Hylobius abietis) is one of the most devastating pests of regenerated coniferous forests in northern and central Europe. Although it is also present and potentially harmful in southern Europe, little attention has been paid to this pest in that region. With the aim of quantifying the potential risk of the pine weevil as a forest pe...

During their long lifespan, pines must cope with simultaneous abiotic and biotic stresses such as drought and herbivory. Mediterranean pines are isohydric species that rapidly close their stomata in response to drought reducing carbon fixation. In such situations, the synthesis of chemical defences could be impaired. Here, we tested the hypothesis...

Interspecific phenotypic variation in plant secondary metabolites (PSM) is often explained by biotic and abiotic factors. However, patterns of variation within species do not clearly fit the theoretical predictions. Exploring how genetics, environment and demographic processes shape such variation among and within populations is crucial for underst...

Fusarium circinatum is a highly virulent invasive pathogen that causes the disease commonly known as Pine Pitch Canker (PPC). On mature trees, the most common symptoms of PPC include resin bleeding, resinous cankers, wilting of needles and dieback. In nurseries the main symptoms are yellowish needles, and wilting of foliage and shoots. PPC is consi...

Understanding pine weevil [Hylobius abietis (L.)] feeding preferences and their relations to chemical defenses of pines may lead to improved protection of conifer seedlings across Europe and Asia. Previous studies showed reduced weevil damage in methyl jasmonate (MeJA) treated seedlings and that weevil preference for Monterey pine (Pinus radiata Ai...

Resistance to herbivores and pathogens is considered a key plant trait with strong adaptive value in trees, usually involving high concentrations of a diverse array of plant secondary metabolites (PSM). Intraspecific genetic variation and plasticity of PSM are widely known. However, their ecology and evolution are unclear, and even the implication...

Key message Adaptation of Pinus brutia and Pinus halepensis to harsh Moroccan environments varied considerably among populations, with variation following marked geographic clines. Context Mediterranean pines are drought tolerant species that play relevant ecological and economic roles in North Africa. Mediterranean pines harbor huge intraspecific...

The airborne inoculum of Fusarium circinatum Nirenberg & O’Donnell, the fungal pathogen causing Pine Pitch Canker (PPC), is one of the main means of spread of the disease in forest stands and forest nurseries. Since this world-wide known pathogen was introduced in Europe, its biology in this newly infested area still remains scarcely known. To shed...

The airborne inoculum of Fusarium circinatum, the fungal pathogen causing Pine Pitch Canker (PPC), is one of the main means of spread of the disease in forest stands and forest nurseries. Since this world-wide known pathogen was introduced in Europe, its biology in this newly infected area still remains scarcely known. To shed more light on this to...

Regeneration of northern conifer forests is commonly performed by reforestation with genetically improved materials obtained from long-term breeding programs focused on productivity and timber quality. Sanitary threats can, however, compromise the realization of the expected genetic gain. Including pest resistance traits in the breeding programs ma...

Light is a major environmental factor that may determine the interaction between plants and herbivores in several ways, including top-down effects through changes in herbivore behavior and bottom-up effects mediated by alterations of plant physiology. Here we explored the relative contribution of these two regulation processes to the outcome of the...

Pinus pinaster harbour large genetic variation between and within populations in many life history traits. Previous research found that the chemical profile of the secondary metabolites are particular of the site of origin of the populations assessed in common gardens. However, these secondary metabolites were explored only in their constitutive st...

Seed size is a relevant predictor of seed survival, seedling phenotype and species recruitment and it is generally accepted that larger seeds give rise to seedlings with improved performance. In pioneer tree species the success in seedling survival is strongly determined by resource availability, which largely varies at diverse spatial scales. Here...

Context‐dependency in species interactions is widespread and can produce concomitant patterns of context‐dependent selection. Masting (synchronous production of large seed crops at irregular intervals by a plant population) has been shown to reduce seed predation through satiation (reduction in rates of seed predation with increasing seed cone outp...

The combination of defensive traits leads to the evolution of 'plant defense syndromes' which should provide better protection against herbivores than individual traits on their own. Defense syndromes can be generally driven by plant phylogeny and/or biotic and abiotic factors. However, we lack a solid understanding of (i) the relative importance o...

Excel file including data used for this paper. (XLSX)

Presentation for Doctoral Defense of Thesis Titled: "Effects of methyl jasmonate on chemical defenses of conifer seedlings in relation to feeding by Hylobius abietis"; at the Royal Institute of Technology, Stockholm, SWEDEN. The work was performed at Ecological Chemistry Group, Division of Organic Chemistry, Head of group & Supervisor: Professor A...

Pine trees are long-lived, widespread organisms that have to cope with multiple biotic stresses during their life cycle. To face against biological aggressions pine trees harbour terpenoids and phenolics as major chemical defences that may avoid or deter the attack providing resistance. Mono and sesquiterpenes, the volatile fraction of oleoresin, h...

Maritime pine can respond to antagonistic interactions with herbivores and pathogens by producing a modified phenotype with increased resistance that usually involves quantitative and qualitative changes in chemical defences. Maritime pine harbour a large intraspecific variation in life history traits, however little is still known about across pop...

The pine wilt disease (PWD), caused by the pinewood nematode (PWN) Bursaphelenchus xylophilus (Steiner et Buhrer) Nickle, is one of the most serious threats to pine forests worldwide. Here we studied several components of susceptibility to PWN infection in a model group of pine species widely distributed in Europe (Pinus pinaster Ait., P. pinea L.,...

Pine trees are long-lived, widespread organisms that have to cope with multiple biotic stressors during its life cycle. To face against biological aggressions pine trees harbour a wide variety of secondary compounds that may avoid or deter the attack providing resistance. Terpenoids and phenolics are the major pine chemical defences. Mono and sesqu...

Conifers exhibit a number of chemical and anatomical mechanisms to defend against pests and pathogens. Theory predicts an increased investment in plant defences under limited nutrient availability, but while this has been demonstrated for chemical defences, it has rarely been shown for anatomical defensive structures. In a long-lived woody plant, w...

Key message Migration ability of the PWN through wood branch tissues of adult Maritime pine trees significantly differed among Iberian provenances and this variation was related to differences in anatomical and chemical defensive traits. Abstract The pinewood nematode or pine wilt nematode (PWN; Bursaphelenchus xylophilus) is one of the most dange...

AimUsing pine trees as a long-lived woody plant model, we analysed the extent to which constitutive and induced allocation to chemical defences were conserved across the phylogeny, and tested the hypothesis that patterns of defensive allocation and defensive strategies differ between Palaearctic and Nearctic pines.LocationCommon-environment study w...

Maritime pine can respond to antagonistic interactions with herbivores and pathogens by producing a modified phenotype with increased resistance. That involves quantitative and qualitative changes in chemical defences in target pine tissues. It is known that both genotype and environmental factors such as resource availability may modulate those in...

Quantitative seed provisioning is an important life-history trait with strong effects on offspring phenotype and fitness. As for any other trait, heritability estimates are vital for understanding its evolutionary dynamics. However, being a trait in between two generations, estimating additive genetic variation of seed provisioning requires complex...

Maritime pine grows naturally under a wide range of climatic conditions, from strongly Atlantic to strongly Mediterranean. Aiming to improve our understanding of the genetic structure and inheritance of drought resistance strategies in the species, we conducted an environmentally controlled experiment to assess the genetic variation and plasticity...

There is increasing evidence that geographic and climatic clines drive the patterns of plant defence allocation and defensive strategies. We quantified early growth rate and both constitutive and inducible chemical defences of 18 Pinaceae species in a common greenhouse environment and assessed their defensive allocation with respect to each species...

Plants have evolved plastic responses to face the multiple stressors they have to cope with, such as light availability and insect herbivory. The former may impact the ability of producing induced defenses in response to herbivory due to conflicts in the allocation of C resources in absence of photosynthesis, and also because light may directly mod...

Herbivore damage commonly initiates an increased synthesis of chemical defensive compounds in attacked plants. Such induced defences are a vital part of plant defence systems, but when herbivore pressure is high, as frequently occurs in man-made ecosystems such as agricultural and forest plantations, plants may suffer considerable damage before ade...

As any other living entity, forest trees must optimize resource investment to growth, reproduction and maintenance but investment in one function may occur at the expense of other functions, resulting in trade-offs that limit maximization of all processes. Global Change is imposing new challenges to Mediterranean forests, in particular combined abi...

Abstract ICEC 2013, a joint conference with ISCE-International Society of Chemical Ecology & APACE -Asia-Pacific Association of Chemical Ecologists: Titled: "VOLATILE TERPENOID RESPONSE FROM METHYL JASMONATE TREATMENT OF FOUR CONIFER SPECIES" Lina LUNDBORG 1, Henrik NORDENHEM 2, Göran NORDLANDER 2, Luis SAMPEDRO 3, Rafael ZAS 3, Anna-Karin BORG-KA...

Trees are massive organisms, with great maintenance costs, long lifespan, delayed reproduction and long life cycles. Just as any other organism on Earth, they must cope with different environments by finely tuning their relative allocation of resources to growth, reproduction and maintenance. Forests -and hence forest trees- are facing new challeng...

The resistance to abiotic stress is increasingly recognised as being impacted by maternal effects, given that environmental conditions experienced by parent (mother) trees affect stress tolerance in offspring. We hypothesised that abiotic environmental maternal effects may also mediate the resistance of trees to biotic stress. The influence of mate...

Mean seed mass of Pinus pinaster seedlings. Seedlings were derived from 10 maternal genotypes clonally replicated in two contrasting maternal environments, one favourable (white bars) and one unfavourable (black bars) for pine growth and reproduction. Means ± standard errors are shown (N = 72). (TIF)

Mean seedling height of Pinus pinaster seedlings. Seedlings were derived from 10 maternal genotypes clonally replicated in two contrasting maternal environments, one favourable (white bars) and one unfavourable (black bars) for pine growth and reproduction. Means ± standard errors are shown (N = 72). (TIF)

Climatic, edaphic and dasometric characteristics of the two contrasting maternal environments. (DOC)

Results of the general linear mixed model for analysis of individual seed mass of Pinus pinaster . (DOC)

Results of the general linear mixed model for analysis of monthly heights (February–October 2011) of the Pinus pinaster seedlings. (DOC)

Necrosis length of Pinus pinaster seedlings four weeks after inoculation with the Fusarium circinatum pathogen. Scale bar = 0.3 cm. (TIF)

The pine wilt disease (PWD) is caused by the nematode Bursaphelenchus xylophilus and affects mainly Pinus pinaster trees, leading to the cut down of thousands of symptomatic and asymptomatic trees every year. In countries like Portugal and Spain, where the resin and wood industries play a very important role in the economy and at a social level, th...

Although maternal environmental effects are increasingly recognized as an important source of phenotypic variation with relevant impacts in evolutionary processes, their relevance in long-lived plants such as pine trees is largely unknown. Here, we used a powerful sample size and a strong quantitative genetic approach to analyse the sources of vari...

The virulent Fusarium circinatum fungus which causes pitch canker disease in pines is now apparently well established in the north of the Iberian Peninsula and represents the main threat to Maritime pine (Pinus pinaster) in this area. The expression of abiotic stress is increasingly recognised as being impacted by maternal effects, given that envir...

The apparent failure of invasions by alien pines in Europe has been explained by the co-occurrence of native pine congeners supporting herbivores that might easily recognize the new plants as hosts. Previous studies have reported that exotic pines show reduced tolerance and capacity to induce resistance to those native herbivores. We hypothesize th...

While plant diversity is well known to increase primary productivity, whether these bottom-up effects are enhanced by reciprocal top-down effects from the third trophic level is unknown. We studied whether pine tree species diversity, aphid-tending ants and their interaction determined plant performance and arthropod community structure. Plant dive...

Context Pinus pinaster Ait. is found in the Iberian Peninsula under Mediterranean and Atlantic conditions. Both climates encounter each other in Galicia (NW Spain), where two bioclimatic regions can be differentiated: coastal and inland. A breeding program was launched in the coastal area, with two breeding and deployment areas delimited. Aims We a...