From photoprotection to growth: shifts in high-light acclimation strategies associated with molecular evolutionary rates in duckweeds
- 1The University of Tokyo
Abstract
Molecular evolutionary rates vary widely among lineages, yet the biological processes generating this variation remain poorly understood. In plants, which lack an early-segregated germline, growth- and environment-dependent physiology could itself influence mutation accumulation and, ultimately, substitution rates. Here we examine this possibility in duckweeds (Araceae, Lemnoideae), whose closely related lineages differ severalfold in sequence divergence. Nonsynonymous and synonymous divergence scaled proportionally across all six lineages examined, indicating that this heterogeneity does not reflect differences in selective constraint and instead points to variation in mutation rate. Lineages without prominent anthocyanin accumulation occupied lower latitudes and, under high light, sustained higher relative growth rates and higher photosynthetic efficiency. Comparing the early-diverging, anthocyanin-accumulating Spirodela polyrhiza with the late-diverging, anthocyanin-free Wolffia australiana revealed contrasting acclimation strategies: S. polyrhiza preferentially induced photoprotective pathways, including anthocyanin biosynthesis and non-photochemical quenching, whereas W. australiana instead expanded mitochondrial oxidative phosphorylation together with the cytosolic translational machinery, and broadly remodeled primary metabolism. Duckweed lineages therefore differ in how they balance photoprotection against photochemical energy use and downstream metabolic capacity, a divergence that may be associated with their lineage-specific molecular evolutionary rates.
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BibTeX
@misc{kawaguchi2026from,
title = {{From photoprotection to growth: shifts in high-light acclimation strategies associated with molecular evolutionary rates in duckweeds}},
author = {Y. W. Kawaguchi and M. Kono and M. Isoda and K. Kawade and H. Tabeta and R. Sasaki and A. Oikawa and M. Y. Hirai and E. Josephine and L. Valerie and N. Katayama},
howpublished = {bioRxiv},
year = {2026},
month = sep,
doi = {10.64898/2026.09.07.749874},
url = {https://www.biorxiv.org/content/10.64898/2026.09.07.749874v1},
note = {CC BY},
}
RIS
TY - UNPB
TI - From photoprotection to growth: shifts in high-light acclimation strategies associated with molecular evolutionary rates in duckweeds
AU - Y. W. Kawaguchi
AU - M. Kono
AU - M. Isoda
AU - K. Kawade
AU - H. Tabeta
AU - R. Sasaki
AU - A. Oikawa
AU - M. Y. Hirai
AU - E. Josephine
AU - L. Valerie
AU - N. Katayama
PY - 2026
DA - 2026/09/07
PB - bioRxiv
DO - 10.64898/2026.09.07.749874
UR - https://www.biorxiv.org/content/10.64898/2026.09.07.749874v1
AB - Molecular evolutionary rates vary widely among lineages, yet the biological processes generating this variation remain poorly understood. In plants, which lack an early-segregated germline, growth- and environment-dependent physiology could itself influence mutation accumulation and, ultimately, substitution rates. Here we examine this possibility in duckweeds (Araceae, Lemnoideae), whose closely related lineages differ severalfold in sequence divergence. Nonsynonymous and synonymous divergence scaled proportionally across all six lineages examined, indicating that this heterogeneity does not reflect differences in selective constraint and instead points to variation in mutation rate. Lineages without prominent anthocyanin accumulation occupied lower latitudes and, under high light, sustained higher relative growth rates and higher photosynthetic efficiency. Comparing the early-diverging, anthocyanin-accumulating Spirodela polyrhiza with the late-diverging, anthocyanin-free Wolffia australiana revealed contrasting acclimation strategies: S. polyrhiza preferentially induced photoprotective pathways, including anthocyanin biosynthesis and non-photochemical quenching, whereas W. australiana instead expanded mitochondrial oxidative phosphorylation together with the cytosolic translational machinery, and broadly remodeled primary metabolism. Duckweed lineages therefore differ in how they balance photoprotection against photochemical energy use and downstream metabolic capacity, a divergence that may be associated with their lineage-specific molecular evolutionary rates.
ER -