MicroRNA156‐mediated changes in leaf composition lead to altered photosynthetic traits during vegetative phase change

Abstract

Plant morphology and physiology change with growth and development. Some of these changes are due to change in plant size and some are the result of genetically programmed developmental transitions. In this study we investigate the role of the developmental transition, vegetative phase change (VPC), on morphological and photosynthetic changes.• We used overexpression of miR156, the master regulator of VPC, to modulate the timing of VPC in Populus tremula x alba, Zea mays and Arabidopsis thaliana to determine its role in trait variation independent of changes in size and overall age.• Here we find that juvenile and adult leaves in all three species photosynthesize at different rates and that these differences are due to phase-dependent changes in specific leaf area (SLA) and leaf N but not photosynthetic biochemistry. Further, we found juvenile leaves with high SLA were associated with better photosynthetic performance at low light levels..

VAL genes regulate vegetative phase change via miR156-dependent and independent mechanisms

“…The 50 proteins with the strongest and most consistent decreasing developmental trend were significantly enriched for Gene Ontology terms related to photosynthesis and carbon fixation (S7 Fig) . In contrast, the 50 proteins with the highest increasing trend score were enriched for GO terms relating to water stress and translation. The finding that younger plants invest more resources in photosynthesis is consistent with a transcriptomic analysis of vegetative development in maize [51], and the enhanced photosynthetic capacity of juvenile plants at low light levels [3].…”

“…The correct timing of these transitions is critical to plant survival and, ultimately, reproductive success. Vegetative phase change describes the transition from juvenileto-adult vegetative growth and is associated with changes to multiple traits, including leaf morphology, light-use efficiency, herbivore resistance and shoot physiology [2][3][4][5]. In Arabidopsis thaliana, the juvenile phase is characterized by small round leaves that lack both trichomes on the abaxial surface and serrations.…”

VALgenes regulate vegetative phase change via miR156-dependent and independent mechanisms

“…In contrast, the 50 proteins with the highest increasing trend score were enriched for GO terms relating to water stress and translation. The finding that younger plants invest more resources in photosynthesis is consistent with a transcriptomic analysis of vegetative development in maize (Beydler et al, 2016), and the enhanced photosynthetic capacity of juvenile plants at low light levels (Lawrence et al, 2020).…”

“…The correct timing of these transitions is critical to plant survival and, ultimately, reproductive success. Vegetative phase change describes the transition from juvenile-to-adult vegetative growth and is associated with changes to multiple traits, including leaf morphology, light-use efficiency, herbivore resistance and shoot physiology (Gou et al, 2011; Lawrence et al, 2020; Leichty and Poethig, 2019; Mao et al, 2017). In Arabidopsis thaliana , the juvenile phase is characterized by small round leaves that lack both trichomes on the abaxial surface and serrations.…”

The carbon economics of vegetative phase change: why plants make juvenile and adult leaves

“…It is unclear why the expected negative relationships between LMA and leaf N or Asat are lacking, as LMA increases during VPC in these species. However, previous work found no phase-specific changes in photosynthetic nitrogen use efficiency (PNUE) (Lawrence et al, 2020), indicating adult leaves somehow compensate for the structural changes that often reduce PNUE in high LMA leaves, potentially through their increased stomatal density which could reduce resistance to CO2 diffusion (Hikosaka, 2004;Feng et al, 2016;Lawrence et al, 2021).…”