Overexpression of a maize BR transcription factor ZmBZR1 in Arabidopsis enlarges organ and seed size of the transgenic plants. (March 2020)

• Record Type: Journal Article
• Authors: Zhang, Xiaoyuan; Guo, Weijun; Du, Danyao; Pu, Li; Zhang, Chunyi
• Is Part Of: Plant science. Volume 292(2020)
• Publication Date: 2020-03
• Subjects: ZmBZR1 -- Brassinosteroid -- Maize -- Transcription factor -- Organ size; Botany -- Periodicals; Botanique -- Périodiques; 580
• DOI: 10.1016/j.plantsci.2019.110378
• Languages: English
• ISSNs: 0168-9452

Abstract

Highlights: BZR1 regulates organ size through BR signal pathway in Arabidopsis . Overexpression of ZmBZR1 caused enlarged organ and seed size in transgenic Arabidopsis plants. ZmBZR1 binds the promoter regions of GRACE and KRP6 and regulates their expression to control the organ size. ZmBZR1 is required for the progressive increase in cells during plant development. Abstract: In plants, the organ size is one of the most important features and regulated by an elaborate developmental program involving both internal and external signals. The steroidal hormone brassinosteroid (BR) plays an important role in regulating the organ size. BRASSINAZOLE RESISTANT 1 ( BZR1 ) is one of important transcription factors that regulate organ size in BR signal pathway in Arabidopsis . The function of BZR1 on organ size is well characterized in Arabidopsis, but poorly understood in maize ( Zea mays ). To understand the mechanism of intrinsic organ size regulated by BZR1 during organogenesis, we identified the maize BZR1 and examined its function in Arabidopsis . Overexpression of ZmBZR1 displayed phenotypes of enlarged cotyledons, rosette leaves, floral organ and seed size in Arabidopsis . The cells in rosette leaves as well as other organs in transgenic ZmBZR1 lines were dramatically larger and longer than those in Col-0. ChIP and RNA-seq analysis showed ZmBZR1 can directly bind to the promoter region of organ size related genes, Germination Repression and Cell Expansion receptor-like kinase (GRACE) and KIP-RELATED PROTEIN6 (KRP6) to regulate their expression, suggesting ZmBZR1 is required for the progressive increase in cells during Arabidopsis development. Collectively, our findings provide significant insights into the mechanisms underlying regulation of organ size mediated by maize BZR1 .