Search

Understanding the causes and limits of population divergence in phenotypic traits is a fundamental aim of evolutionary biology, with the potential to yield predictions of adaptation to environmental change. Reciprocal transplant experiments and the evaluation of optimality models suggest that local adaptation is common but not universal, and some studies suggest that trait divergence is highly constrained by genetic variances and covariances of complex phenotypes. We analyze a large database of population divergence in plants and evaluate whether evolutionary divergence scales positively with standing genetic variation within populations (evolvability), as expected if genetic constraints are evolutionarily important. We further evaluate differences in divergence and evolvability– divergence relationships between reproductive and vegetative traits and between selfing, mixed-mating, and outcrossing species, as these factors are expected to influence both patterns of selection and evolutionary potentials. Evolutionary divergence scaled positively with evolvability. Furthermore, trait divergence was greater for vegetative traits than for floral (reproductive) traits, but largely independent of the mating system. Jointly, these factors explained ~40% of the variance in evolutionary divergence. The consistency of the evolvability–divergence relationships across diverse species suggests substantial predictability of trait divergence. The results are also consistent with genetic constraints playing a role in evolutionary divergence. adaptation | evolvability | genetic constraints | macroevolution

Tillgång på alternativa växtskyddsmetoder är viktiga för att kunna tillämpa integrerat växtskydd. I detta projekt undersökte vi hur förekomst av fröskadegörare och fröproduktion hos vitklöver påverkas av att flytta fält kortare respektive längre avstånd mellan år.

I den här rapporten presenteras en utredning om behov och möjligheter för långliggande fältförsök för rot- och knölgrödor. Utredningen baseras huvudsakligen på intervjuer med representanter från universitet, näring, rådgivning och finansiärer, och även på en mindre uppföljande enkät till de intervjuade. Intervjuerna visar på att det finns ett brett intresse av långliggande fältförsök med frågeställningar som explicit rör rot- och knölgrödor. Frågeställningar som anses särskilt viktiga rör markbearbetning, växtskydd och växtföljd men även andra aspekter föreslås. Det finns ett intresse av att samarbeta om den här typen av försök men för många aktörer är det viktigt att man då kan få ut även kortsiktigare resultat och att dessa ska vara användbara för organisationen. Den främsta utmaningen kan vara att säkra långsiktig finansiering men även experimentdesign och organisation runt försöken är viktiga att beakta för att de ska ha ett långsiktigt värde.

Multiple biotic and abiotic stresses challenge plants growing in agricultural fields. Most molecular studies have aimed to understand plant responses to challenges under controlled conditions. However, studies on field-grown plants are scarce, limiting application of the findings in agricultural conditions. In this study, we investigated the composition of apoplastic proteomes of potato cultivar Bintje grown under field conditions, i.e., two field sites in June–August across two years and fungicide treated and untreated, using quantitative proteomics, as well as its activity using activity-based protein profiling (ABPP). Samples were clustered and some proteins showed significant intensity and activity differences, based on their field site and sampling time (June–August), indicating differential regulation of certain proteins in response to environmental or developmental factors. Peroxidases, class II chitinases, pectinesterases, and osmotins were among the proteins more abundant later in the growing season (July–August) as compared to early in the season (June). We did not detect significant differences between fungicide Shirlan treated and untreated field samples in two growing seasons. Using ABPP, we showed differential activity of serine hydrolases and β-glycosidases under greenhouse and field conditions and across a growing season. Furthermore, the activity of serine hydrolases and β-glycosidases, including proteins related to biotic stress tolerance, decreased as the season progressed. The generated proteomics data would facilitate further studies aiming at understanding mechanisms of molecular plant physiology in agricultural fields and help applying effective strategies to mitigate biotic and abiotic stresses. CA extern

Even though floral scent is of major importance for pollinator attraction, it is less investigated than other floral traits. Previous studies suggest the importance of joint exploration of olfactory and visual floral cues to understand plant-pollinator interactions. We investigated flower scents in Collinsia heterophylla, a bee-pollinated, annual herb a with mixed-mating system combining self- and outcross-pollination. In Collinsia, floral size and development variation is related to mating system, ranging from large-flowered mixed-mating species to small-flowered self-pollinated species. However, to our knowledge, flower scent has not been described in any species in the genus. We also studied whether flower-emitted volatiles were coupled to presence versus absence of a coloured band on the upper lip within a population in C. heterophylla, and if these colour morphs affected pollinator visitation. We performed headspace collections of volatiles in the greenhouse from potted flowering plants, and compared these to controls in the bud stage. Flower-specific volatiles were highly dominated by terpenoid compounds typical of bee-pollinated plants, such as beta-myrcene, (Z)- and (E)-ocimene and sesquiterpenes (E)-alpha-bergamotene and beta-sesquiphellandrene. The aliphatic ester methyl hexanoate was also prominent, together with additional esters, whereas methyl cinnamate constituted the only aromatic compound. Floral colour morphs showed no qualitative difference in volatiles, but the coloured morph produced significantly higher quantities for seven of the 26 individual flower compounds. A field experiment performed within a natural population, using behavioural observations and florescent dyes dusted on the flowers, could not detect any differences in pollinator visitation between colour morphs. We conclude that C. heterophylla flowers emit volatile compounds commonly associated with attraction of their most important pollinators. It would be highly interesting to explore the function of floral scent for pollinator attraction and relate floral scent to mating system variation across Collinsia for a better understanding of pollinator influence on floral evolution.

We evaluated oomycete presence and abundance in the rhizosphere of wild perennial Solarium species to investigate the presence of plant pathogenic or mycoparasitic species. Furthermore, we investigated whether these plant species could function as hosts, or associated plants, for off-season survival of economically important pathogens. We collected soil samples in Sweden from Solarium dulcamara and as a control from Vitis vinifera over all four seasons of a year, and in New Zealand from Solarium nigrum and Solarium laciniatum in the summer. Species identification, confirmed by ITS and Cox2 sequencing, and root infection assays on the crop plant Solarium tuberosum and on S. dulcamara, suggested the presence of mainly Pythiales species. In Sweden, we also found evidence for the presence of Phytophthora infestans, the causal agent of potato late blight, in the rhizosphere of S. dulcamara. These Ph. infestans isolates had no negative effects on root growth of S. dulcamara in Sweden, but were more pathogenic on potato leaves than a common lab strain. Oomycete diversity measures indicated a high similarly between seasons and countries. In conclusion, our study suggests a previously unknown overwintering strategy for the pathogen Ph. infestans, indicating a possible influence of the wild species S. dulcamara on the epidemiology of potato late blight in Sweden.