Red and blue light treatments of ripening bilberry fruits reveal differences in signalling through abscisic acid‐regulated anthocyanin biosynthesis

Abstract

The biosynthesis of anthocyanins has been shown to be influenced by light quality. However, the molecular mechanisms underlying the light‐mediated regulation of fruit anthocyanin biosynthesis are not well understood. In this study, we analysed the effects of supplemental red and blue light on the anthocyanin biosynthesis in non‐climacteric bilberry (Vaccinium myrtillus L.). After 6 days of continuous irradiation during ripening, both red and blue light elevated concentration of anthocyanins, up to 12‐ and 4‐folds, respectively, compared to the control. Transcriptomic analysis of ripening berries showed that both light treatments up‐regulated all the major anthocyanin structural genes, the key regulatory MYB transcription factors and abscisic acid (ABA) biosynthetic genes. However, higher induction of specific genes of anthocyanin and delphinidin biosynthesis alongside ABA signal perception and metabolism were found in red light. The difference in red and blue light signalling was found in 9‐cis‐epoxycarotenoid dioxygenase (NCED), ABA receptor pyrabactin resistance‐like (PYL) and catabolic ABA‐8'hydroxylase gene expression. Red light also up‐regulated expression of soluble N‐ethylmaleimide‐sensitive factor attachment protein receptor (SNARE) domain transporters, which may indicate involvement of these proteins in vesicular trafficking of anthocyanins during fruit ripening. Our results suggest differential signal transduction and transport mechanisms between red and blue light in ABA‐regulated anthocyanin and delphinidin biosynthesis during bilberry fruit ripening.

Transcriptome Analysis Reveals Differences in Anthocyanin Accumulation in Cotton (Gossypium hirsutum L.) Induced by Red and Blue Light

“…Generally, UV – B and blue light are considered to be the main light sources affecting anthocyanin accumulation ( Xu et al, 2014 ; Tao et al, 2018 ; Kim et al, 2020 ; Li et al, 2021 ). Besides, evidence suggests that red light also seems to play a positive role in anthocyanin biosynthesis ( Zhang et al, 2018 ; Samkumar et al, 2021 ). Interestingly, red light can promote anthocyanin accumulation more than blue light in bilberry, but it is the opposite in strawberry ( Lekkham et al, 2016 ; Zhang et al, 2018 ; Samkumar et al, 2021 ).…”

“…Besides, evidence suggests that red light also seems to play a positive role in anthocyanin biosynthesis ( Zhang et al, 2018 ; Samkumar et al, 2021 ). Interestingly, red light can promote anthocyanin accumulation more than blue light in bilberry, but it is the opposite in strawberry ( Lekkham et al, 2016 ; Zhang et al, 2018 ; Samkumar et al, 2021 ). In this study, we used a comparative transcriptomics approach to analyze the effect of red and blue light on anthocyanin biosynthesis and the genes involved in regulation of the effect using leaves of Huiyuan, a red Upland cotton accession with the same mutation as that found in the red leaf mutant R1 .…”

“…As one of the most important environmental stimulants, light can control the synthesis of anthocyanins by influencing photosynthesis and consequently the synthesis of sugar, phenylalanine and other precursor substances, and by regulating the expression or activity of structural genes and regulatory genes of the anthocyanin biosynthesis pathway ( Wei et al, 2017 ). In the process of photoinduced anthocyanin synthesis, light quality is one of the key factors affecting the synthesis and accumulation of anthocyanins ( Zhang et al, 2018 ; Kim et al, 2020 ; Samkumar et al, 2021 ). In addition, the effects of light quality on the expression of genes related to anthocyanin biosynthesis are different among species ( Tao et al, 2018 ; An et al, 2020 ; Kim et al, 2020 ; Samkumar et al, 2021 ).…”

“…In the process of photoinduced anthocyanin synthesis, light quality is one of the key factors affecting the synthesis and accumulation of anthocyanins ( Zhang et al, 2018 ; Kim et al, 2020 ; Samkumar et al, 2021 ). In addition, the effects of light quality on the expression of genes related to anthocyanin biosynthesis are different among species ( Tao et al, 2018 ; An et al, 2020 ; Kim et al, 2020 ; Samkumar et al, 2021 ). Higher plants employ multiple sensory photoreceptors to coordinate their response to different lights ranging from UV-B to far-red wavelengths.…”

Light Induced Regulation Pathway of Anthocyanin Biosynthesis in Plants

“…Furthermore, blue light signal transduction module CRY-COP1-HY5 contributes to the anthocyanin biosynthesis induced by blue light in red pear, but red light does not affect anthocyanin accumulation [112]. However, in ripening bilberry fruits, blue and red light are effective in inducing anthocyanin and delphinidin accumulation via CRY2/COP1 and HY5 or ABA-signal transduction [134]. Red light, blue light, and red/blue compound light also induce the strawberry fruit coloration [135].…”