Feedback loop promotes sucrose accumulation in cotyledons to facilitate sugar ethylene signaling mediated, etiolated seedling greening

Xin Rong Mu, Chen Tong, Xing Tang Fang, Qin-Xin Bao, Li Na Xue, Wei-Ying Meng, Chang Yue Liu, Gary J. Loake, Xiao Ying Cao, Ji-Hong Jiang, Lai-Sheng Meng

Research output: Contribution to journalArticlepeer-review

Abstract

De-etiolation is indispensable for seedling survival and development. However, how sugars regulate de-etiolation and how sugars induce ethylene (ET) for seedlings to grow out of soil remain elusive. Here, we reveal how a sucrose (Suc) feedback loop promotes de-etiolation by inducing ET biosynthesis. Under darkness, Suc in germinating seeds preferentially induces 1-amino-cyclopropane-1-carboxylate synthase (ACS7; encoding a key ET biosynthesis enzyme) and associated ET biosynthesis, thereby activating ET core component ETHYLENE-INSENSITIVE3 (EIN3). Activated EIN3 directly inhibits the function of Suc transporter 2 (SUC2; a major Suc transporter) to block Suc export from cotyledons and thereby elevate Suc accumulation of cotyledons to induce ET. Under light, ET-activated EIN3 directly inhibits the function of phytochrome A (phyA; a de-etiolation inhibitor) to promote de-etiolation. We therefore propose that under darkness, the Suc feedback loop (Suc-ACS7-EIN3-|SUC2-Suc) promotes Suc accumulation in cotyledons to guarantee ET biosynthesis, facilitate de-etiolation, and enable seedlings to grow out of soil.
Original languageEnglish
Article number110529
Number of pages20
JournalCell Reports
Volume38
Issue number11
DOIs
Publication statusPublished - 15 Mar 2022

Keywords

  • cotyledon greening
  • ETHYLENE-INSENSITIVE3
  • EIN3
  • phytochrome A
  • phyA
  • ethylene
  • SUCROSE transporter 2
  • SUC2
  • sucrose phloem loading

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