Light Control of Salt-Induced Proline Accumulation Is Mediated by ELONGATED HYPOCOTYL 5 in Arabidopsis

Hajnalka Kovács, Dávid Aleksza, Abu Imran Baba, Anita Hajdu, Anna Mária Király, Laura Zsigmond, Szilvia Z. Tóth, László Kozma-Bognár, László Szabados

Research output: Contribution to journalArticle


Plants have to adapt their metabolism to constantly changing environmental conditions, among which the availability of light and water is crucial in determining growth and development. Proline accumulation is one of the sensitive metabolic responses to extreme conditions; it is triggered by salinity or drought and is regulated by light. Here we show that red and blue but not far-red light is essential for salt-induced proline accumulation, upregulation of Δ1-PYRROLINE-5-CARBOXYLATE SYNTHASE 1 (P5CS1) and downregulation of PROLINE DEHYDROGENASE 1 (PDH1) genes, which control proline biosynthetic and catabolic pathways, respectively. Chromatin immunoprecipitation and electrophoretic mobility shift assays demonstrated that the transcription factor ELONGATED HYPOCOTYL 5 (HY5) binds to G-box and C-box elements of P5CS1 and a C-box motif of PDH1. Salt-induced proline accumulation and P5CS1 expression were reduced in the hy5hyh double mutant, suggesting that HY5 promotes proline biosynthesis through connecting light and stress signals. Our results improve our understanding on interactions between stress and light signals, confirming HY5 as a key regulator in proline metabolism.

Original languageEnglish
Article number1584
JournalFrontiers in Plant Science
Publication statusPublished - Dec 10 2019



  • Arabidopsis
  • gene expression regulation
  • light signalling
  • proline accumulation

ASJC Scopus subject areas

  • Plant Science

Cite this

Kovács, H., Aleksza, D., Baba, A. I., Hajdu, A., Király, A. M., Zsigmond, L., Tóth, S. Z., Kozma-Bognár, L., & Szabados, L. (2019). Light Control of Salt-Induced Proline Accumulation Is Mediated by ELONGATED HYPOCOTYL 5 in Arabidopsis. Frontiers in Plant Science, 10, [1584].