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Biology subjects

Mansfield, S. D.

Publications and source records attributed to Mansfield, S. D..

3 recordsLinked to original sources

Geographic and Climatic Origins Shape the Leaf Metabolome of Populus trichocarpa

O_LIBackground and Aims: Chemodiversity is a fitness-relevant trait shaped by genetics, environment, and their interaction. Populus trichocarpa naturally inhabits broad climatic gradients and shows extensive variation in specialised metabolism. We investigated whether provenance and climate of origin imprint leaf chemodiversity and class-level relationships under common-garden conditions, and how these patterns relate to gene expression. C_LIO_LIMethods: Leaves from 87 P. trichocarpa genotypes representing 22 provenances from the west coast of North America growing in a common garden were profiled by untargeted FT-ICR-MS (1030 features) and targeted LC-MS/MS. A subset of 41 genotypes was subject to RNA-seq analyses. We tested whether provenance influenced multivariate patterns and whether metabolomic differences were related to geographic and climatic distance, where chemodiversity was quantified as Functional Hill Diversity. C_LIO_LIKey Results: P. trichocarpa metabolomes differed among origins despite shared growth conditions and showed distance-decay with both geography and climate. North-south extremes were well separated, and within-drainage samples shared high similarity. Flavonoid and isoprenoid pools strongly co-varied across individuals, whereas isoprene synthase activity did not predict total isoprenoids. Transcriptomes showed within-pathway coherence but limited overall provenance separation. C_LIO_LIConclusions: Leaf chemistry in P. trichocarpa retains signatures of geographic origin even under common-garden conditions. Coordinated investment in flavonoids and isoprenoids, together with among-origin differences in functional chemodiversity, reveals provenance-linked chemical fingerprints that complement genomic and metabolic trait data for climate-informed deployment. C_LI

plant biology↗

Cytokinins control secondary cell wall formation in the inflorescence stem of Arabidopsis

Spatiotemporal control over developmental programs is vital to all organisms. Here we show that cytokinin (signaling) deficiency leads to early secondary cell wall (SCW) formation in Arabidopsis inflorescence stem that associates with precocious upregulation of a SCW transcriptional cascade controlled by NAC TFs (NSTs). We demonstrate that cytokinin signaling through the AHK2/3 and the ARR1/10/12 suppresses the expression of several NSTs and SCW formation in the apical portions of stems. Exogenous cytokinin application reconstituted both proper development and apical-basal gradient of NST1 and NST3 in a cytokinin biosynthesis-deficient mutant. We show that AHK2 and AHK3 required functional NST1 or NST3 to control SCW initiation in the interfascicular fibers, further evidencing that cytokinins act upstream of NSTs transcription factors. The premature onset of a rigid SCW biosynthesis and altered expression of NST1/3 and VND6/7 due to cytokinin deficiency led to the formation of smaller tracheary elements (TEs) and impaired hydraulic conductivity. We conclude that cytokinins downregulate NSTs to inhibit premature SCW formation in the apical part of the inflorescence stem, facilitating thus the development of fully functional TEs and interfascicular fibers. Summary statementCytokinins attenuate premature secondary cell wall (SCW) formation via downregulating the expression of NAC TFs, the master switches of SCW transcriptional cascade, thus affecting the tracheary elements size and conductivity.

plant biology↗

Distinct and overlapping functions of Miscanthus sinensis MYB transcription factors SCM1 and MYB103 in lignin biosynthesis

Cell wall recalcitrance is a major constraint for the exploitation of lignocellulosic biomass as renewable resource for energy and bio-based products. Transcriptional regulators of the lignin biosynthetic pathway represent promising targets for tailoring lignin content and composition in plant secondary cell walls. A wealth of research in model organisms has revealed that transcriptional regulation of secondary cell wall formation is orchestrated by a hierarchical transcription factor (TF) network with NAC TFs as master regulators and MYB factors in the lower tier regulators. However, knowledge about the transcriptional regulation of lignin biosynthesis in lignocellulosic feedstocks, such as Miscanthus, is limited. Here, we characterized two Miscanthus MYB TFs, MsSCM1 and MsMYB103, and compared their transcriptional impact with that of the master regulator MsSND1. In Miscanthus leaves MsSCM1 and MsMYB103 are expressed at growth stages associated with lignification. Ectopic expression of MsSCM1 and MsMYB103 in tobacco leaves was sufficient to trigger secondary cell wall deposition with distinct sugar and lignin composition. Moreover, RNA-seq analysis revealed that the transcriptional responses to MsSCM1 and MsMYB103 overexpression showed extensive overlap with the response to MsSND1, but were distinct from each other, underscoring the inherent complexity of secondary cell wall formation. Together, MsSCM1 and MsMYB103 represent interesting targets for manipulations of lignin content and composition in Miscanthus towards tailored biomass.

plant biology↗