KNOX Gene Function in Plant Development

KNOX (KNOTTED1-LIKE HOMEOBOX) genes encode a family of homeodomain transcription factors that play a pivotal role in the regulation of meristem maintenance, organ initiation and tissue patterning across land plants. Class I KNOX genes are expressed primarily in the shoot apical meristem (SAM), where they promote indeterminacy by repressing differentiation programmes and by modulating phytohormone pathways, notably cytokinin and gibberellin. Through direct autoregulation and feedback loops, these proteins sustain meristematic stem cell populations and ensure the iterative formation of leaves, stems and floral organs. Class II KNOX genes, in contrast, tend to be more broadly expressed and are implicated in the transition to determinacy, often antagonising Class I activity to fine-tune organogenesis. Functional heterodimerisation with BELL-like (BLH) proteins confers target specificity, allowing KNOX complexes to regulate downstream genes involved in hormone metabolism, cell wall remodelling and boundary formation. Across diverse taxa—from mosses to flowering plants—duplicated KNOX paralogues have evolved divergent roles, contributing to morphological diversity in leaf form, stem architecture and reproductive structures. Recent advances in three-dimensional imaging, genome editing and transcriptome profiling have illuminated how spatiotemporal dynamics of KNOX expression integrate endogenous signals and environmental cues to shape plant form and resilience, with implications for crop improvement and adaptation to changing climates.

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KNOX Gene Function in Plant Development publication trend

The graph below shows the total number of articles in knox gene function in plant development across all publications each year (not limited to Nature Index journals).

Technical terms

KNOX gene: A homeobox transcription factor that regulates meristem maintenance and organ patterning.

Homeodomain: A conserved DNA-binding motif of approximately 60 amino acids found in transcription factors.

Shoot apical meristem (SAM): A population of undifferentiated cells at the tip of the shoot responsible for organ initiation.

BELL domain: A conserved region in BELL-like proteins mediating heterodimerisation with KNOX partners.

Phytohormone: A plant hormone such as cytokinin, gibberellin or brassinosteroid that regulates growth and development.

Lignin: A complex polymer deposited in cell walls that provides structural support and water transport efficiency.

References

1. LoBLH6 interacts with LoMYB65 to regulate anther development through feedback regulation of gibberellin synthesis in lily. Horticulture Research (2024).
2. AGAMOUS-LIKE24 controls pistil number in Japanese apricot by targeting the KNOTTED1-LIKE gene KNAT2/6-a. Plant Physiology (2024).
3. In Silico Genome-Wide Analysis of the Pear (Pyrus bretschneideri) KNOX Family and the Functional Characterization of PbKNOX1, an Arabidopsis BREVIPEDICELLUS Orthologue Gene, Involved in Cell Wall and Lignin Biosynthesis. Frontiers in Genetics (2019).
4. Positive Autoregulation of a KNOX Gene Is Essential for Shoot Apical Meristem Maintenance in Rice. The Plant Cell (2011).
5. Antagonistic Roles for KNOX1 and KNOX2 Genes in Patterning the Land Plant Body Plan Following an Ancient Gene Duplication. PLOS Genetics (2015).
6. Evolution, diversification, and expression of KNOX proteins in plants. Frontiers in Plant Science (2015).
7. Control of Oriented Tissue Growth through Repression of Organ Boundary Genes Promotes Stem Morphogenesis. Developmental Cell (2016).
8. Ring the BELL and tie the KNOX: roles for TALEs in gynoecium development. Frontiers in Plant Science (2014).