Comparative transcriptome analysis reveals an insight into the candidate genes involved in anthocyanin and scent volatiles biosynthesis in colour changing flowers of Combretum indicum

Abstract

Combretum indicum is a widely cultivated ornamental species displaying the distinct phenomenon of floral colour change. Flowers display a gradual colour change from white to red, attributed to increased cyanidin 3-O glucoside in petal tissues. The differently coloured flowers also emanate a complex blend of VOCs with trans-linalool oxide (furanoid) as the major compound in the emission profile.• To understand molecular mechanisms regulating floral colour shifts and scent biosynthesis, we performed Illumina transcriptome sequencing, including de novo assembly and functional annotation, for the two stages of floral maturation (white and red). Homology analysis with functional classification identified 84 and 42 candidate genes associated with pigment and scent biosynthesis, respectively. Genes encoding transcription factors, such as MYB, ERF, WD40, WRKY, NAC, bHLH and bZIP, that play critical roles in regulating specialized metabolism were also identified in the transcriptome data.• Differences in expression of genes were consistent with accumulation patterns of anthocyanins in the two different flower colours. A clear upregulation of flavonoid biosynthesis genes in red flower tissue is associated with increased pigment content. RT-qPCR-based expression analyses gave results consistent with the RNA-Seq data, suggesting the sequencing data are consistent and reliable.• This study presents the first report of genetic information for C. indicum. Gene sequences generated from RNA-Seq, along with candidate genes identified by pathway mapping and their expression profiles, provide a valuable resource for subsequent studies towards molecular understanding of specialized metabolism in C. indicum flowers.

The NAC transcription factors play core roles in flowering and ripening fundamental to fruit yield and quality

“…Because the NAC family exists from aquatic green algae to higher terrestrial plants, its members participate in the formation of the organ boundaries of plants transiting from vegetative growth to reproductive growth and are related to flower development and fruit ripening, which are essential to crop yield and quality (Maugarny-Calès et al, 2016;Ma et al, 2017;Mathew and Agarwal, 2018;Forlani et al, 2021;Singh et al, 2021;Liu G. S. et al, 2022). Thereby, in recent years, much progress has been made toward understanding the molecular mechanisms regulated by NAC TFs in flower development (Guo et al, 2022;Liang et al, 2022;Liu X. et al, 2022;Wang et al, 2022;Ghissing et al, 2023) and fruit ripening (Fu B. L. et al, 2021;Gao et al, 2021;Kou et al, 2021;Gao et al, 2022;Liu B. et al, 2022;Qi et al, 2022). In this review, we mainly summarize up-to-date advances on the basic properties, function, and action mechanisms of NACs in flower formation, flowering, and fruit ripening to improve our understanding of the molecular basis of crop yield and quality mediated by NAC TFs.…”

De novo transcriptome analysis of Dysoxylum binectariferum to unravel the biosynthesis of pharmaceutically relevant specialized metabolites

“…The isoprene unit (C5) is synthesized from the MEP pathway and is engaged in the formation of mono-(C10), Di-(C20) and other terpenoids. Whereas the isoprene unit from the MVA pathway is used in the synthesis of triterpene (C30) and sesquiterpenes (C15) ( Schilmiller et al., 2009 ; Zhao et al., 2013 ; Ghissing et al., 2023 ). In the D. binectariferum transcriptome, around 269 unigenes (70 key enzymes) were found to be associated with the terpenoid pathways ( Figure 4 ; Figure S2 ).…”

“…The transcriptome showed 12 unigenes involved in monoterpenoid biosynthesis and 21 unigenes encoding 7 enzymes in gibberellin biosynthesis (2 beta-dioxygenase GA2ox, 7 unigenes, ent-kaurenoic acid monooxygenase KAO, 4 unigenes) ( Figures 3B , 4 ). In total, the MEP pathway predominates in the roots and MVA pathway in the leaf which contributes to the generation of many volatile molecules ( Inaba and Ito-Inaba, 2010 ; Tomar et al., 2013 ; Pérez et al., 2022 ) and they play key roles in the biosynthesis of various defensive compounds ( Yan et al., 2021 ; Naini et al., 2022 ; Ghissing et al., 2023 ).…”

The paradox of plant preference: the malaria vectorsAnopheles gambiaeandAnopheles coluzziiselect suboptimal food sources for their survival and reproduction

“…Furthermore, while the relative importance of visual vs chemical cues in our multiple-choice trap device is unknown, it is recognized that visual cues, including color and contrast, contribute to mosquito attraction, with lightly-colored flowers, particularly white ones, being typically appealing to mosquitoes 57 . This may explain why C. indicum was an attractive species, given its unique characteristic of displaying a floral color change phenomenon 58,59 . These flowers indeed create a striking contrast, both at the intra- and inter-flower levels, by transitioning gradually from white to pink and finally to red 58,59 .…”

“…This may explain why C. indicum was an attractive species, given its unique characteristic of displaying a floral color change phenomenon 58,59 . These flowers indeed create a striking contrast, both at the intra- and inter-flower levels, by transitioning gradually from white to pink and finally to red 58,59 . In contrast, the flowers of I. coccinea and C. pulcherrima have darker and less contrasting colors.…”