Biology subjects

Oldroyd, G. E.

Publications and source records attributed to Oldroyd, G. E..

3 recordsLinked to original sources

bioRxiv2023

Light sensitive short hypocotyl (LSH) confer symbiotic nodule identity in the legume Medicago truncatula

Legumes grow specialized root nodules that are distinct from lateral roots in morphology and function, with nodules intracellularly hosting beneficial nitrogen-fixing bacteria that provide the plant with a nitrogen source. We have previously shown that a lateral root-like program underpins nodule initiation, but there must be additional developmental programs that confer nodule identity. Here, we show that two members of the LIGHT SENSITIVE SHORT HYPOCOTYL (LSH) transcription factor family, predominantly known to define organ boundaries and meristem complexity in the shoot, function as regulators of nodule organ identity. LSH1/LSH2 function upstream of and together with the known nodule regulators Nuclear Factor Y-A1 and NODULE ROOT1/2. The principal outcome of LSH1/LSH2 function is the production of cells able to accommodate nitrogen-fixing bacteria, the unique nodule feature. We conclude that the coordinate recruitment of a pre-existing primordium identity program, in parallel to a root initiation program, underpins the divergence between lateral roots and nodules.

plant biology↗

bioRxiv2021

Plants export 2-monopalmitin and supply both fatty acyl and glyceryl moieties to arbuscular mycorrhizal fungi

Arbuscular mycorrhizal fungi (AMF) rely on their host plants to provide them with fatty acids (FA), but the precise form(s) in which they are supplied is still unclear. Here we show that ectopic expression of the transcription factor REQUIRED FOR ARBUSCULAR MYCORRHIZATION 1 (RAM1) can drive secretion of 2-monoacylglycerols (2MGs) from Medicago truncatula roots and that their main FA moiety is palmitic acid, although myristic acid and stearic acid were also detected. RAM1-dependent 2MG secretion requires the acyl-acyl carrier protein thioesterase FATM, the glycerol-3-phosphate (G3P) acyltransferase RAM2 and the ATP binding cassette transporter STR. Furthermore, 14C glycerol labelling experiments using mycorrhizal M. truncatula roots that are deficient in glycerol kinase, FAD-dependent G3P dehydrogenase and the G3P acyltransferase RAM2 suggest that most of the glyceryl moieties in Rhizophagus irregularis storage lipids are provided by their host plant through the 2MG pathway. Taken together, our data support the hypothesis that the plant exports 2MGs across the peri-arbuscular membrane in mycorrhizal roots and that the AMF receive and utilise both the FA and glyceryl moieties to make their storage lipids.

plant biology↗

bioRxiv2019

An ancestral signalling pathway is conserved in plant lineages forming intracellular symbioses

Plants are the foundation of terrestrial ecosystems and their colonization of land was facilitated by mutualistic associations with arbuscular mycorrhizal fungi. Following that founding event, plant diversification has led to the emergence of a tremendous diversity of mutualistic symbioses with microorganisms, ranging from extracellular associations to the most intimate intracellular associations, where fungal or bacterial symbionts are hosted inside plant cells. Through analysis of 271 transcriptomes and 122 plant genomes, we demonstrate that the common symbiosis signalling pathway controlling the association with arbuscular mycorrhizal fungi and with nitrogen-fixing bacteria specifically co-evolved with intracellular endosymbioses, including ericoid and orchid mycorrhizae in angiosperms and ericoid-like associations of bryophytes. In contrast, species forming exclusively extracellular symbioses like ectomycorrhizae or associations with cyanobacteria have lost this signalling pathway. This work unifies intracellular symbioses, revealing conservation in their evolution across 450 million years of plant diversification.

plant biology↗