Project description:Winter dormancy is an adaptative mechanism that temperate and boreal trees have developed to protect their meristems against low temperatures. In apple trees (Malus domestica), cold temperatures induce bud dormancy at the end of summer/beginning of the fall. Apple buds stay dormant during winter until they are exposed to a period of cold, after which they can resume growth (budbreak) and initiate flowering in response to warm temperatures in spring. It is well-known that small RNAs modulate temperature responses in many plant species, but however, how small RNAs are involved in genetic networks of temperature-mediated dormancy control in fruit tree species remains unclear. Here, we have made use of a recently developed ARGONAUTE (AGO)-purification technique to isolate small RNAs from apple buds. A small RNA-seq experiment resulted in the identification of small RNAs that change their pattern of expression in apple buds during dormancy.
Project description:Background biology: Global warming has accelerated in recent decades, with the Arctic warming 2–3 times faster than the global average. As a result boreal species are expanding into the Arctic, at a pace reflecting environmental warming. Nevertheless, the poleward expansion of boreal marine species is restricted by their ability to tolerate low water temperatures, and in the case of intertidal species, sub-zero air temperatures during winter. In Greenland, however, the number of days with extreme sub-zero air temperatures has decreased by more than 50% since the 1950’s, suggesting that the low air temperature constraint is weakening. Although boreal intertidal species could potentially benefit from this warmer climate to establish populations in the Arctic, recent work has shown that local intertidal summer air temperatures in Greenland can exceed 36°C. This temperature is above the thermoregulatory capacity of many boreal intertidal species, including the highly abundant blue mussel Mytilus edulis. Therefore will further colonisation of M. edulis in Greenland be inhibited by the increasingly warm summer temperatures. Aim of experiment: Intertidal animals (Greenland blue mussel M. edulis) were sampled in situ on the first warm days of the year from the inner (warmer) and outer (cooler) regions of the Godthåbsfjorden around Nuuk (64°N) to examine the fjord temperature gradient effect. In addition, subtidal M. edulis were also collected and subjected to two acute temperature shocks of 22 and 32°C, which represented common and extreme summer air temperatures for intertidal habitats near Nuuk.
Project description:MicroRNAs (miRNAs) are single strand small non-coding RNAs that regulate target mRNAs at post-transcription level. Winter wheat (Triticum aestivum L.), is an important crop plant all over the world. Long term cold exposure (vernalization) is necessary for winter wheat transition from vegetative growth to reproductive growth, yet the involvement of miRNAs in these stages remains unknown. Therefore, we performed next generation sequencing of small RNAs profiles in crown tissues at three-leaf stage, winter dormancy stage, spring greenup stage and jointing stage.
Project description:MicroRNAs (miRNAs) are small non-coding RNAs that regulate target mRNAs by inducing degradation or preventing translation of their target mRNAs. Winter wheat, Triticum aestivum., is an important crop plant, yet there are only a few studies on the association of miRNAs and growth and development of winter wheat grown in the field. Here we carried out experimental analysis of miRNAs in wheat leaves by analyzing small RNA profiles at different growth stages.
Project description:Bud dormancy in perennials in boreal and temperate ecosystems is crucial for survival in harsh winter. Dormancy is released by prolonged exposure to low temperatures and is followed by reactive growth in the spring. Lysine acetylation (Kac) is one of the major post-translational modifications (PTMs) involved in plant response to environment signals. However, little information is available on the effects of Kac modification on bud dormancy release. Here, we report the dynamics of lysine acetylome in hybrid poplar (Populus tremula x alba) dormant buds. A total number of 7,594 acetyl sites from 3,281 acetyl proteins were identified, representing the largest to date dataset of lysine acetylome in plants. Of them, 229 proteins were differentially acetylated during bud dormancy release and were involved mainly in the primary metabolism. Site-directed mutagenesis enzymatic assays showed that acetylation strongly modified the activities of two key enzymes of primary metabolism, pyruvate dehydrogenase (PDH) and isocitrate dehydrogenase (IDH). We thus propose that Kac of enzymes could be an important strategy for reconfiguration of metabolic processes during bud dormancy release. In all, our results reveal the importance of Kac in bud dormancy release and give a new perspective to understand the molecular mechanisms of tree’s seasonal growth.
Project description:Flavonoids are stress-inducible metabolites important for plant-microbe interactions. In contrast to their well-known function in initiating rhizobia nodulation in legumes, it is unclear whether and how flavonoids may contribute to plant stress resistance through affecting non-nodulating bacteria in the root microbiome. Here we show how flavonoids preferentially attracts Aeromonadaceae in Arabidopsis thaliana root microbiome and how flavonoid-dependent recruitment of an Aeromona spp. results in enhanced plant Na_H1 resistance.