Differential localization of flavonoid glucosides in an aquatic plant implicates different functions under abiotic stress

Abstract

Flavonoids may mediate UV protection in plants either by screening of harmful radiation or by minimizing the resulting oxidative stress. To help distinguish between these alternatives, more precise knowledge of flavonoid distribution is needed. We used confocal laser scanning microscopy (cLSM) with the “emission fingerprinting” feature to study the cellular and subcellular distribution of flavonoid glucosides in the giant duckweed (Spirodela polyrhiza), and investigated the fitness effects of these compounds under natural UV radiation and copper sulphate addition (oxidative stress) using common garden experiments indoors and outdoors. cLSM “emission fingerprinting” allowed us to individually visualize the major dihydroxylated B‐ring‐substituted flavonoids, luteolin 7‐O‐glucoside and luteolin 8‐C‐glucoside, in cross‐sections of the photosynthetic organs. While luteolin 8‐C‐glucoside accumulated mostly in the vacuoles and chloroplasts of mesophyll cells, luteolin 7‐O‐glucoside was predominantly found in the vacuoles of epidermal cells. In congruence with its cellular distribution, the mesophyll‐associated luteolin 8‐C‐glucoside increased plant fitness under copper sulphate addition but not under natural UV light treatment, whereas the epidermis‐associated luteolin 7‐O‐glucoside tended to increase fitness under both stresses across chemically diverse genotypes. Taken together, we demonstrate that individual flavonoid glucosides have distinct cellular and subcellular locations and promote duckweed fitness under different abiotic stresses.

Transgenerational non-genetic inheritance has fitness costs and benefits under recurring stress in the clonal duckweed Spirodela polyrhiza

“…To assess whether pre-treatment effects on biomass accumulation were due to altered accumulation of defensive metabolites, we measured the concentrations of the major mono- and di-hydroxylated B-ring-substituted flavonoids in offspring, the latter of which were previously found to be associated with copper resistance in S. polyrhiza [33]. Depending on the pre-treatment and recovery phase combination, copper pre-treatment enhanced the accumulation of the dihydroxylated B-ring-substituted flavonoids, including elevated basal and induced levels as well as only elevated induced levels (= primed) after up to 15 generations of recovery (Student's t -tests; figure 3).…”

Rhizospheric Bacillus amyloliquefaciens Protects Capsicum annuum cv. Geumsugangsan From Multiple Abiotic Stresses via Multifarious Plant Growth-Promoting Attributes

“…These processes can lead to the spread of, for example, heavy metals, which can create severe ecological problems even at low levels ( Wuana and Okieimen, 2011 ). There are other abiotic stresses that are more location specific, including frost ( Keep et al, 2021 ; Simioniuc et al, 2021 ), ultraviolet radiation ( Böttner et al, 2021 ; Navarro et al, 2021 ), and floods ( Khan et al, 2020 ; Liu et al, 2021 ).…”

Comparative Analysis of Flavonoid Metabolites in Foxtail Millet (Setaria italica) with Different Eating Quality

“…The flavonoid metabolites in different buckwheat varieties also provided a theoretical basis for the sufficient utilization of special buckwheat varieties [ 45 ]. Flavonoids in plant leaves play vital roles in defending against abiotic stresses [ 46 ]. Researchers have clarified the accumulation and variations of more than 300 metabolites in the leaves of foxtail millet at three-leaf and five-leaf stages [ 47 ].…”