Evolution and function of red pigmentation in land plants

Abstract

Background Land plants commonly produce red pigmentation as a response to environmental stressors, both abiotic and biotic. The type of pigment produced varies among different land plant lineages. In the majority of species they are flavonoids, a large branch of the phenylpropanoid pathway. Flavonoids that can confer red colours include 3-hydroxyanthocyanins, 3-deoxyanthocyanins, sphagnorubins and auronidins, which are the predominant red pigments in flowering plants, ferns, mosses and liverworts, respectively. However, some flowering plants have lost the capacity for anthocyanin biosynthesis and produce nitrogen-containing betalain pigments instead. Some terrestrial algal species also produce red pigmentation as an abiotic stress response, and these include both carotenoid and phenolic pigments. Scope In this review we examine: which environmental triggers induce red pigmentation in non-reproductive tissues; theories on the functions of stress-induced pigmentation; the evolution of the biosynthetic pathways; and structure-function aspects of different pigment types. We also compare data on stress-induced pigmentation in land plants with those for terrestrial algae, and discuss possible explanations for the lack of red pigmentation in the hornwort lineage of land plants. Conclusions The evidence suggests that pigment biosynthetic pathways have evolved numerous times in land plants to provide compounds that have red colour to screen damaging photosynthetically active radiation but that also have secondary functions that provide specific benefits to the particular land plant lineage.

Exposure to strong irradiance exacerbates photoinhibition and suppresses N resorption during leaf senescence in shade-grown seedlings of fullmoon maple (Acer japonicum)

“…Anthocyanins are known to be synthesized from accumulated sugars in leaves during autumn ( Stitt and Hurry, 2002 ; Hughes et al., 2022 ). Besides photoprotection, recently, a possible function of anthocyanins has been proposed as a sugar-buffer to moderate sugar feedback regulation, which prevents early sugar-mediated leaf senescence ( Ono et al., 2001 ; Landi et al., 2015 ; Lo Piccolo et al., 2018 ; Lo Piccolo and Landi, 2021 ; Davies et al., 2022 ). Leaves in red-leafed Prunus cerasifera var.…”

Post‐secretory synthesis of a natural analog of iron‐gall ink in the black nectar of Melianthus spp.

“…Our work addresses two overarching hypotheses: that colored nectars contain novel pigment chemistries; and these pigments serve as visual attractants for prospective pollinators. With respect to the first hypothesis, it appears that almost all plant pigments are retained inside of cells (especially in vacuoles and plastids Davies et al ., 2022; Rodriguez‐Concepcion & Daros, 2022) instead of being exported. Therefore, extracellular pigments, like those found in colored nectars, are rare.…”

Different photoprotective strategies for white leaves between two co‐occurring Actinidia species

“…Anthocyanins may also scavenge ROS directly. Although anthocyanins may be located far from the site of ROS production in the leaf (Manetas, 2006), O 2 ˙ − in the chloroplasts can rapidly convert into H 2 O 2 (long half‐life ROS species); thus, anthocyanins can scavenge H 2 O 2 , which can then be transported from chloroplasts into vacuoles (Davies et al, 2022). Thirdly, some intermediate products in anthocyanin biosynthetic, such as flavonoids and simple phenolics, may also execute ROS scavenging function (Saito & Yamazaki, 2002).…”