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

Author(s):  
Erica Lawrence ◽  
Clint Springer ◽  
Brent Helliker ◽  
Scott Poethig

Abstract Across plant species and biomes, a conserved set of leaf traits govern the economic strategy used to assimilate and invest carbon. As plants age, they face new challenges that may require shifts in this leaf economic strategy. In this study, we investigate the role of the developmental transition, vegetative phase change (VPC), in altering carbon economics as plants age. We used overexpression of miR156, the master regulator of VPC, to modulate the timing of VPC in Populus tremula x alba, Arabidopsis thaliana and Zea mays to understand the impact of this transition on leaf economic traits, including construction cost, payback time, and return on investment. Here we find that VPC regulates the shift from a low-cost, quick return juvenile strategy to a high-cost, high-return adult strategy. The juvenile strategy is advantageous in light-limited conditions, whereas the adult strategy provides greater returns in high-light. The transition between these strategies is correlated with the developmental decline in the level of miR156, suggesting that is regulated by the miR156/SPL pathway. Our results provide an eco-physiological explanation for the existence of juvenile and adult leaf types, and suggest that natural selection for these alternative economic strategies could be an important factor in plant evolution.

2020 ◽  
Author(s):  
Erica H. Lawrence ◽  
Clint J. Springer ◽  
Brent R. Helliker ◽  
R. Scott Poethig

SummaryPlant 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.This study establishes a role for VPC in leaf composition and photosynthetic performance across diverse species and environments. Variation in leaf traits due to VPC are likely to provide distinct benefits under specific environments and, as a result, selection on the timing of this transition could be a mechanism for environmental adaptation.


eLife ◽  
2013 ◽  
Vol 2 ◽  
Author(s):  
Li Yang ◽  
Mingli Xu ◽  
Yeonjong Koo ◽  
Jia He ◽  
R Scott Poethig

Nutrients shape the growth, maturation, and aging of plants and animals. In plants, the juvenile to adult transition (vegetative phase change) is initiated by a decrease in miR156. In Arabidopsis, we found that exogenous sugar decreased the abundance of miR156, whereas reduced photosynthesis increased the level of this miRNA. This effect was correlated with a change in the timing of vegetative phase change, and was primarily attributable to a change in the expression of two genes, MIR156A and MIR156C, which were found to play dominant roles in this transition. The glucose-induced repression of miR156 was dependent on the signaling activity of HEXOKINASE1. We also show that the defoliation-induced increase in miR156 levels can be suppressed by exogenous glucose. These results provide a molecular link between nutrient availability and developmental timing in plants, and suggest that sugar is a component of the leaf signal that mediates vegetative phase change.


2021 ◽  
Author(s):  
Jim P. Fouracre ◽  
Jia He ◽  
Victoria J. Chen ◽  
Simone Sidoli ◽  
R. Scott Poethig

SummaryHow organisms control when to transition between different stages of development is a key question in biology. In plants, epigenetic silencing by Polycomb repressive complex 1 (PRC1) and PRC2 plays a crucial role in promoting developmental transitions, including from juvenile-to-adult phases of vegetative growth. It is well established that PRC1/2 repress the master regulator of vegetative phase change, miR156, leading to the transition to adult growth, but how this process in temporally regulated is unknown. Here we investigate whether transcription factors in the VIVIPAROUS/ABI3-LIKE (VAL) gene family provide the temporal signal for the epigenetic repression of miR156. Exploiting a novel val1 allele, we found that VAL1 and VAL2 redundantly regulate vegetative phase change by controlling the overall level, rather than temporal dynamics, of miR156 expression. Furthermore, we discovered that VAL1 and VAL2 also act independently of miR156 to control this important developmental transition.


2021 ◽  
Author(s):  
Erica H. Lawrence ◽  
Aaron R. Leichty ◽  
Erin E. Doody ◽  
Cathleen Ma ◽  
Steven H. Strauss ◽  
...  

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