Biology subjects

Dickinson, H. G.

Publications and source records attributed to Dickinson, H. G..

3 recordsLinked to original sources

bioRxiv2022

Misexpression of the Homologues of Bryophyte Gametophyte-to-Sporophyte Control Genes in Arabidopsis Results in Germline Reprogramming and Phenotypes that Mirror Apomictic Development

Evidence from the model bryophytes Physcomitrium and Marchantia suggests that a BELL-KNOX genetic module acts as a master regulator controlling sporophyte identity. Investigating any conservation of this system in flowering plants has proved challenging, but studies of the Arabidopsis eostre mutant and naturally apomictic angiosperms point to ectopic activation of KNOX and BELL transcription factors mediating the switch from sexual to apomictic development. We show here that in Arabidopsis, ectopic expression, under a germline-specific promoter, of KNOX and BELL genes not normally expressed in the gametophytes both disrupts germ cell specification and causes defects in cell identity throughout gametophyte development - some mirroring events seen in naturally apomictic plants. A better understanding of this TALE-HD genetic module in flowering plants may thus help to unravel the molecular control of higher plant life cycles, while providing a route to engineering synthetic apomixis in crops. This study also highlights the utility of applying data from bryophytes, where the ontogeny transitions are spatio-temporally distinct, to apomixis research in angiosperms.

plant biology↗

bioRxiv2019

Two Receptor-Like Kinases Required For Arabidopsis Endodermal Root Organisation Shape The Rhizosphere Microbiome

The Casparian Strip (CS) constitutes a physical diffusion barrier to water and nutrients in plant roots, and is formed by the polar deposition of lignin polymer in the endodermis. This precise pattern of lignin deposition is thought to be mediated by the scaffolding activity of membrane-bound Casparian Strip domain proteins (CASPs). However, we show that endodermis-specific receptor-like kinase 1 (ERK1) and ROP Binding Kinase1 (RBK1) are also involved in this intricate process, with the former playing an essential role both in the localization of CASP1 and in lignin deposition. We further characterised ERK1 and determined its subcellular localisation in the cytoplasm and nucleus of the endodermis, as well as provide evidence for its involvement in a signalling pathway together with the circadian clock regulator, Time for Coffee (TIC). We also show that disruption to CS organisation and increased suberisation in the endodermis due to loss of function of either ERK1 or TIC collectively leads to an altered root microbiome composition. Thus, our work reveals additional players in the complex cascade of signalling events operating in the root endodermis to establish both the CS diffusion barrier and the microbial composition of the rhizosphere.

plant biology↗

bioRxiv2019

A Musashi-Related Protein Is Essential For Gametogenesis In Arabidopsis

Musashi (Msi) proteins are an evolutionarily conserved group of RNA-binding proteins, required for targeted control of mRNA translation during many important developmental processes in animals. Most notably, Msi proteins play important roles during both spermatogenesis and oogenesis. Msi proteins also exist in plants but these are largely uncharacterized. Here we report the functional characterization of an Arabidopsis Msi ortholog ABORTED GAMETOPHYTE 2 (AOG2), which encodes a protein containing two RNA recognition motifs and an ER-targeting signal. AOG2-GFP translational fusions were localized to the ER in transient assays, suggesting that AOG2 most likely binds to ER-targeted mRNAs. We show that disrupted AOG2 function leads to a high rate of both ovule and seed abortion, and that homozygous loss of function mutants are embryo lethal. Furthermore, we demonstrate that AOG2 is required to establish asymmetry during pollen mitosis I, and that loss of AOG2 function leads to loss of pollen viability. Collectively the results reveal that AOG2 is required for the establishment of polarity and/or the progression of mitosis during gametophyte development in Arabidopsis, and thus Msi-related proteins have an evolutionarily conserved role in gametogenesis in both animals and plants.\n\nSIGNIFICANCE STATEMENTABORTED GAMETOPHYTE 2 (AOG2) encodes a Musashi-related RNA-binding protein that is required for gametogenesis and embryogenesis in Arabidopsis. AOG2 is required for the establishment of polarity and/or the progression of mitosis during gametophyte development in Arabidopsis, and thus Musashi-related proteins have an evolutionarily conserved role in gametogenesis in both animals and plants.

plant biology↗