Affiliation:
1. Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Bhopal, Bhopal Bypass Road, Bhauri, Bhopal 462066, Madhya Pradesh, India
Abstract
Abstract
Cotyledon opening is a key morphological change that occurs in seedlings during de-etiolation. Brassinosteroids (BRs) inhibit the opening of cotyledons in darkness while light promotes cotyledon opening. The molecular regulation of the interplay between light and BR to regulate cotyledon opening is not well understood. Here, we show the B-box protein BBX32 negatively regulates light signaling and promotes BR signaling to inhibit cotyledon opening in Arabidopsis (Arabidopsis thaliana). BBX32 is highly expressed in the cotyledons of seedlings during de-etiolation. bbx32 and 35S:BBX32 seedlings exhibit enhanced and reduced cotyledon opening, respectively, in response to both light and brassinazole treatment in dark, suggesting that BBX32 mediates cotyledon opening through both light and BR signaling pathways. BBX32 expression is induced by exogenous BR and is upregulated in bzr1-1D (BRASSINAZOLE RESISTANT1-1D). Our in vitro and in vivo interaction studies suggest that BBX32 physically interacts with BZR1. Further, we found that PHYTOCHROME-INTERACTING FACTOR 3 (PIF3) interacts with BBX32 and promotes BR-mediated cotyledon closure. BBX32, BZR1, and PIF3 regulate the expression of common target genes that modulate the opening and closing of cotyledons. Our work suggests BBX32 integrates light and BR signals to regulate cotyledon opening during de-etiolation.
Funder
CSIR
DST-INSPIRE (Department of Science and Technology – Innovation in Science Pursuit for Inspired Research) respectively for fellowships
DST-INSPIRE
UGC
Department of Biotechnology
MHRD-STARS (Ministry for Human Resource Development – Scheme for Transformational and Advanced Research in Sciences
Publisher
Oxford University Press (OUP)
Subject
Plant Science,Genetics,Physiology
Cited by
29 articles.
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