TY - JOUR
T1 - BZR1 and BES1 transcription factors mediate brassinosteroid control over root system architecture in response to nitrogen availability
AU - Al-Mamun, Mahamud
AU - Cazzonelli, Christopher Ian
AU - Krishna, Priti
N1 - Publisher Copyright:
Copyright © 2024 Al-Mamun, Cazzonelli and Krishna.
PY - 2024
Y1 - 2024
N2 - Plants modify their root system architecture (RSA) in response to nitrogen (N) deficiency. The plant steroidal hormone, brassinosteroid (BR), plays important roles in root growth and development. This study demonstrates that optimal levels of exogenous BR impact significant increases in lateral root length and numbers in Arabidopsis seedlings under mild N-deficient conditions as compared to untreated seedlings. The impact of BR on RSA was stronger under mild N deficiency than under N-sufficient conditions. The BR effects on RSA were mimicked in dominant mutants of BZR1 and BES1 (bzr1-1D and bes1-D) transcription factors, while the RSA was highly reduced in the BR-insensitive mutant bri1-6, confirming that BR signaling is essential for the development of RSA under both N-sufficient and N-deficient conditions. Exogenous BR and constitutive activity of BZR1 and BES1 in dominant mutants led to enhanced root meristem, meristematic cell number, and cortical cell length. Under mild N deficiency, bzr1-1D displayed higher fresh and dry shoot weights, chlorophyll content, and N levels in the shoot, as compared to the wild type. These results indicate that BR modulates RSA under both N-sufficient and N-deficient conditions via the transcription factors BES1/BZR1 module and confers tolerance to N deficiency.
AB - Plants modify their root system architecture (RSA) in response to nitrogen (N) deficiency. The plant steroidal hormone, brassinosteroid (BR), plays important roles in root growth and development. This study demonstrates that optimal levels of exogenous BR impact significant increases in lateral root length and numbers in Arabidopsis seedlings under mild N-deficient conditions as compared to untreated seedlings. The impact of BR on RSA was stronger under mild N deficiency than under N-sufficient conditions. The BR effects on RSA were mimicked in dominant mutants of BZR1 and BES1 (bzr1-1D and bes1-D) transcription factors, while the RSA was highly reduced in the BR-insensitive mutant bri1-6, confirming that BR signaling is essential for the development of RSA under both N-sufficient and N-deficient conditions. Exogenous BR and constitutive activity of BZR1 and BES1 in dominant mutants led to enhanced root meristem, meristematic cell number, and cortical cell length. Under mild N deficiency, bzr1-1D displayed higher fresh and dry shoot weights, chlorophyll content, and N levels in the shoot, as compared to the wild type. These results indicate that BR modulates RSA under both N-sufficient and N-deficient conditions via the transcription factors BES1/BZR1 module and confers tolerance to N deficiency.
KW - BES1
KW - brassinosteroid
KW - BZR1
KW - lateral roots
KW - nitrogen deficiency
KW - root system architecture
UR - http://www.scopus.com/inward/record.url?scp=85193741352&partnerID=8YFLogxK
U2 - 10.3389/fpls.2024.1387321
DO - 10.3389/fpls.2024.1387321
M3 - Article
AN - SCOPUS:85193741352
SN - 1664-462X
VL - 15
JO - Frontiers in Plant Science
JF - Frontiers in Plant Science
M1 - 1387321
ER -