Biology subjects

Brurberg, M. B.

Publications and source records attributed to Brurberg, M. B..

4 recordsLinked to original sources

bioRxiv2024

CRISPR-Cas9 mediated deletions of FvMYB46 reduces fruit set and biosynthesis of flavonoids in Fragaria vesca

Secondary metabolites produced by the phenylpropanoid pathway, which is regulated by transcription factors of the MYB family, play crucial roles in this early phase of fruit development. The MYB46 transcription factor is a key regulator of secondary cell wall structure and lignin and flavonoid biosynthesis in many plants, but little is known about its activity in flowers and berries in F. vesca. For functional analysis of FvMYB46, we designed a CRISPR-Cas9 construct with an endogenous F. vesca specific U6-promoter for efficient and specific expression of two gRNAs targeting the first exon of FvMYB46. This generated mutants with an in frame 81-bp deletion of the first conserved MYB-domain or an out of frame 82-bp deletion potentially knocking out the gene function. In both types of mutant plants, pollen germination and the frequency of flowers developing to mature berries was significantly reduced compared to wild type. Transcriptomic analysis of flowers demonstrated that FvMYB46 is positively regulating the expression of genes involved in pollen germination, homeostasis of reactive oxygen species (ROS) and the phenylpropanoid pathway, including secondary cell wall biosynthesis and flavonoid biosynthesis, while has a negative impact on carbohydrate metabolism. In FvMYB46-mutant flowers, the flavonols and flavan-3-olscontent, especially epicatechin, quercetin-glucoside and kaempferol-3-coumaroylhexoside were reduced, and we observed a local reduction of lignin content in anthers. Together these results suggest that MYB46 control fertility and efficient fruit set by regulating cell wall structure, flavonoid biosynthesis, carbohydrate metabolism and ROS-signaling in flowers and early fruit development in F. vesca.

plant biology↗

bioRxiv2023

Climate, host and geography shape insect and fungal communities of trees

Non-native pests, climate change, and their interactions are likely to alter relationships between trees and tree-associated organisms with consequences for forest health. To understand and predict such changes, factors structuring tree-associated communities need to be determined. Here, we analysed the data consisting of records of insects and fungi collected from dormant twigs from 155 tree species at 51 botanical gardens or arboreta in 32 countries. Generalized dissimilarity models revealed similar relative importance of studied climatic, host-related and geographic factors on differences in tree-associated communities. Mean annual temperature, phylogenetic distance between hosts and geographic distance between locations were the major drivers of dissimilarities. The increasing importance of high temperatures on differences in studied communities indicate that climate change could affect tree-associated organisms directly and indirectly through host range shifts. Insect and fungal communities were more similar between closely related vs. distant hosts suggesting that host range shifts may facilitate the emergence of new pests. Moreover, dissimilarities among tree-associated communities increased with geographic distance suggesting that human-mediated transport may facilitate the introductions of new pests. The results of this study highlight the need to limit the establishment of tree pests and increase the resilience of forest ecosystems to changes in climate.

ecology↗

bioRxiv2019

Induced and primed defence responses of Fragaria vesca to Botrytis cinerea infection

1.Strawberry is a high-value crop that suffers huge losses from diseases such as grey mould caused by the necrotrophic fungal pathogen Botrytis cinerea. Pesticides are heavily used to protect the strawberry crop, which raises environmental and human health concerns and promotes the evolution of pesticide resistant strains. Upregulating or priming the plants defences may be a more environmentally sustainable way of increasing disease resistance. Using Fragaria vesca as a model for the commercially grown octaploid strawberry Fragaria x ananassa, we investigated the transcriptional reprogramming of strawberry upon B. cinerea infection and the effectiveness of four priming chemicals in protecting strawberry against grey mould. First, we found that the transcriptional reprogramming of strawberry upon B. cinerea infection overlapped substantially with the transcriptome responses induced by Phytophthora cactorum (Toljamo et al., 2016), including the genes involved in jasmonic acid (JA), salicylic acid (SA), ethylene (ET) and terpenoid pathways. Furthermore, we investigated the effectiveness of previously identified priming chemicals in protecting strawberry against B. cinerea. The level of upregulated or primed resistance depended on the priming chemical itself ({beta}-aminobutyric acid (BABA), methyl jasmonate (MeJ), (R)-{beta}-homoserine (RBH), prohexadione-calcium (ProCa)) and the application method used (foliar spray, soil drench, seed treatment). Overall, RBH effectively primed strawberry defences against B. cinerea, whereas BABA and ProCa were not effective and MeJ showed mixed effects. Our results not only identify ways to effectively upregulate or prime strawberry defences against B. cinerea, but also provide novel insights about strawberry defences that may be applied in future crop protection schemes.

plant biology↗

bioRxiv2018

Bioinformatic characterisation of the effector repertoire of the strawberry pathogen Phytophthora cactorum

The oomycete pathogen Phytophthora cactorum causes crown rot, a major disease of cultivated strawberry. We report the draft genome of P. cactorum isolate 10300, cultured from symptomatic Fragaria x ananassa tissue. Our analysis revealed that there are a large number of genes encoding putative secreted effectors in the genome, including nearly 200 RxLR domain containing effectors, 77 Crinklers (CRN) grouped into 38 families and numerous apoplastic effectors, such as phytotoxins (PcF proteins) and necrosis inducing proteins. As in other Phytophthora species, the genomic environment of many RxLR and CRN genes differed from core eukaryotic genes, a hallmark of the two-speed genome. We found genes homologous to known Phytophthora infestans avirulence genes including Avr1, Avr3b, Avr4, Avrblb1 and AvrSmira2 indicating effector sequence conservation between Phytophthora species of Clade 1A and 1C. The reported P. cactorum genome sequence and associated annotations represent a comprehensive resource for avirulence gene discovery in other Phytophthora species from Clade 1 and will facilitate effector informed breeding strategies in other crops.

pathology↗