Systematic mutagenesis reveals dominant–minor paralog configurations in the rice GA2ox gene family
Journal
Frontiers in plant science
Journal Volume
17
Start Page
1813123
ISSN
1664-462X
Date Issued
2026
Author(s)
Hsieh, Kun-Ting
Shiue, Shiau-Yu
Liao, Yi-Chun
農業部農業試驗所
農業部農業試驗所
Li, Wen-Hsiung
Chen, Liang-Jwu
Abstract
Gibberellin 2-oxidases (GA2oxs) deactivate bioactive gibberellins and play essential roles in regulating rice growth and development. However, the relative contributions of individual paralogs, their redundancy patterns, and dominant-minor relationships within this multigene family remain poorly understood. Clarifying these relationships is important for understanding how GA2ox genes coordinately influences plant development in rice.
To address these questions, we generated 36 CRISPR/Cas9-edited rice lines targeting all nine genes, including single-, double-, triple-, and quadruple-gene knockout mutants, and systematically analyzed their effects on agronomic traits to compare gene-specific and combinatorial functions.
In Class II, is the main regulator of plant height, whereas alone showed no discernable effect. Double mutants of these two genes showed a modest height increase and a reduced grain number but retained normal flowering time, indicating partial redundancy in regulating plant height and grain number, with as the dominant contributor. In Class I, , , and function as dominant suppressors of stem elongation, whereas showed no phenotypical effect in single mutants but contributed to stem elongation control when disrupted together with other Class I members. The quadruple Class I mutant exhibited the greatest increase in plant height but reduced grain weight and fertility. In Class III, and regulated plant height, with additionally influencing grain size, whereas showed no detectable function.
These findings reveal a hierarchical but partially redundant regulatory framework within the rice GA2ox gene family, in which dominant and minor paralogs contribute unequally to GA-related growth regulation. Our study provides allele-validated genetic evidence for functional diversification among paralogs and highlights how redundancy and specialization are integrated to stabilize hormone-regulated development and key agronomic traits in rice.
Subjects
CRISPR-induced variants
GA homeostasis
gibberellin 2-oxidases
paralog configurations
plant height regulation
rice
Type
journal article