Ethylene mediates the branching of the jasmonate-induced flavonoid biosynthesis pathway by suppressing anthocyanin biosynthesis in red Chinese pear fruits.

Junbei Ni,Ling Gao,Yuanjun Li,Minjie Qian,Lei Yin,Yuanwen Teng,Songling Bai,Juncai Li,Jiaqi Shen,Åke Strid,Ruiyan Tao,Yuan Zhao

doi:10.1111/pbi.13287

Abstract

SummaryFlavonoid accumulation in most fruits is enhanced by ethylene and jasmonate. However, little is known about the hormone functions related to red pear fruit coloration or their combined effects and potential underlying mechanisms. Various treatments were used to investigate the flavonoid metabolite profile and pear transcriptome to verify the effects of ethylene and jasmonate on flavonoid biosynthesis in red pear fruits as well as the mechanism behind this. Ethylene inhibits anthocyanin biosynthesis in red Chinese pear fruits, whereas jasmonate increases anthocyanin and flavone/isoflavone biosyntheses. The branching of the jasmonate‐induced flavonoid biosynthesis pathway is determined by ethylene. Co‐expression network and Mfuzz analyses revealed 4,368 candidate transcripts. Additionally, ethylene suppresses PpMYB10 and PpMYB114 expression via TF repressors, ultimately decreasing anthocyanin biosynthesis. Jasmonate induces anthocyanin accumulation through transcriptional or post‐translational regulation of TFs‐like MYB and bHLH in the absence of ethylene. However, jasmonate induces ethylene biosynthesis and the associated signalling pathway in pear, thereby decreasing anthocyanin production, increasing the availability of the precursors for flavone/isoflavone biosynthesis and enhancing deep yellow fruit coloration. We herein present new phenotypes and fruit coloration regulatory patterns controlled by jasmonate and ethylene, and confirm that the regulation of fruit coloration is complex.

Highlights

Flavonoids, which are vital secondary metabolites in plants, are determinants of fruit quality and commercial value because they influence fruit colour, nutritive value, aroma and antioxidant properties
Our results identified ethyleneand jasmonate-responsive transcripts, which are correlated with anthocyanin biosynthesis or the deep yellow coloration of fruits
The ETH treatment induced ethylene production (Figure 1c). These results indicated that ethylene inhibited lightinduced anthocyanin biosynthesis in the red pear fruits

Summary

Flavonoid accumulation in most fruits is enhanced by ethylene and jasmonate. Various treatments were used to investigate the flavonoid metabolite profile and pear transcriptome to verify the effects of ethylene and jasmonate on flavonoid biosynthesis in red pear fruits as well as the mechanism behind this. Ethylene inhibits anthocyanin biosynthesis in red Chinese pear fruits, whereas jasmonate increases anthocyanin and flavone/isoflavone biosyntheses. The branching of the jasmonateinduced flavonoid biosynthesis pathway is determined by ethylene. Ethylene suppresses PpMYB10 and PpMYB114 expression via TF repressors, decreasing anthocyanin biosynthesis. Jasmonate induces anthocyanin accumulation through transcriptional or posttranslational regulation of TFs-like MYB and bHLH in the absence of ethylene. Jasmonate induces ethylene biosynthesis and the associated signalling pathway in pear, thereby decreasing anthocyanin production, increasing the availability of the precursors for flavone/ isoflavone biosynthesis and enhancing deep yellow fruit coloration. We present new phenotypes and fruit coloration regulatory patterns controlled by jasmonate and ethylene, and confirm that the regulation of fruit coloration is complex

Introduction

Results

Experimental procedures