Project description:Illumina HiSeq technology was used to generate mRNA profiles from mycorrhizal Quercus robur roots. Tuber melanosporum, T. aestivum and T.magnatum mycorrhizal root tips were harvested and used for RNA extraction. Paired-end reads of 100 bp were generated and aligned to Quercus robur CDS using CLC Genomics Workbench 9.
Project description:Priming of plant defenses provides increased plant protection against herbivores and reduces the allocation costs of defense. Defense priming in woody plants remains obscure, in particular due to plant development traits such as the endogenous rhythmic growth displayed by oaks (Quercus robur). By using bioassays with oak microcuttings, and by combining transcriptomic and metabolomic analyses, we investigated how leaf herbivory by Lymantria dispar and root inoculation with the ectomycorrhizal fungus Piloderma croceum prime oak defenses. We further investigated how defense priming is modulated by rhythmic growth of the oaks. A first herbivory challenge in oak leaves primed newly grown leaves for an enhanced induction of jamonic acid (JA)-related direct defenses, or enhanced emission of volatiles, depending on the specific growth stage at which the plants where challenged. Root inoculation with Piloderma abolished the enhanced induction of JA-related defenses and volatile emission. Our results indicate that a first herbivore attack primes direct and indirect defenses of newly formed oak leaves, and that the specific display of defense priming is modulated by rhythmic growth. Our results further show that the priming memory in oaks can be transmitted to the next growth cycle even to the leaves of the new shoot unit.
Project description:Tree ring features are affected by environmental factors and therefore are the basis for dendrochronological studies to reconstruct past environmental conditions. Oak wood often provides the data for these studies because of the durability particularly of oak heartwood and, hence the availability of samples spanning long time periods of the distant past. Wood formation is regulated in part by epigenetic mechanisms such as DNA methylation. Studies in the methylation state of DNA preserved in oak heartwood thus could identify epigenetic tree ring features informing on past environmental conditions. We investigated the feasibility of such studies using heartwood samples core-drilled from the trunks of standing oak trees spanning the AD 1776-2014. Heartwood contains little DNA, and large amounts of phenolic compounds known to hinder the preparation of high-throughput sequencing libraries. We sequenced whole-genome and DNA methylome libraries for oak heartwood up to 100 and 50 years of age, respectively. However, only 56 genomic regions with sufficient coverage for quantitative methylation analysis were identified, suggesting that the high-throughput sequencing of DNA will be in principal feasible for wood formed <100 years ago is impeded by the reduction in library complexity caused by the bisulfite treatment used to generate the oak methylome.
