Open AccessType-B response regulators of rice play key roles in growth, development, and cytokinin signaling
Author(s) -
Jennifer M. Worthen,
Maria V. Yamburenko,
Jeewoo Lim,
Zachary L. Nimchuk,
Joseph J. Kieber,
G. Schäller
Publication year - 2019
Publication title -
development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.15
H-Index - 36
eISSN - 1477-9129
pISSN - 0950-1991
DOI - 10.1242/dev.174870
Subject(s) - biology , cytokinin , mutant , arabidopsis , transcription factor , microbiology and biotechnology , genetics , tor signaling , gene , botany , auxin
Cytokinins are plant hormones that play critical roles in growth and development. Although cytokinin signaling is well characterized in the model dicot Arabidopsis, we are only beginning to understand its role in monocots such as rice and other cereals of agronomic importance. Here, we employed primarily a CRISPR/Cas9 gene editing approach to characterize the roles played by a key family of transcription factors—the type-B response regulators (RRs)—in cytokinin signaling of the major crop species rice. Results from the analysis of single rr mutants as well as higher-order rr21/22/23 mutant lines reveal functional overlap as well as subfunctionalization within members of the gene family. Mutant phenotypes associated with decreased activity of rice type-B RRs include effects on leaf and root growth, inflorescence architecture, flower development and fertilization, trichome formation, and cytokinin sensitivity. Development of the stigma brush involved in pollen capture is compromised in the rr21/22/23 mutant, whereas anther development is compromised in the rr24 mutant. Novel as well as conserved roles for type-B RRs in the growth and development of a monocot as compared to dicots were identified.