Root cone angle is enlarged in docs1 LRR-RLK mutants in rice

Area of Science:

• Plant Molecular Biology
• Genetics
• Developmental Biology

Background:

• The DEFECTIVE IN OUTER CELL LAYER SPECIFICATION 1 (DOCS1) gene is part of the Leucine-Rich Repeat Receptor-Like Kinase (LRR-RLK) subfamily.
• DOCS1 was initially identified in rice (Oryza sativa) for its role in aluminum sensitivity.
• The original docs1-1 mutant had a nonsense mutation in the DOCS1 kinase domain.

Purpose of the Study:

• To generate and characterize new loss-of-function mutants of the DOCS1 gene.
• To investigate the function of DOCS1 in plant development, particularly in root and gravitropic responses.

Main Methods:

• CRISPR-Cas9 gene editing technology was used to create a new docs1 loss-of-function mutant (docs1-2).
• Phenotypic analysis of docs1 mutants, including root hair development, outer cell layer identity, and gravitropism.
• Comparison of the new docs1-2 mutant with the existing docs1-1 mutant.

Main Results:

• The new docs1-2 mutant exhibited similar phenotypes to docs1-1, suggesting docs1-1 is a null allele.
• Both docs1 mutants displayed aluminum sensitivity, reduced root hairs, and mixed outer root cell layer identities.
• DOCS1 plays a role in root cap development, leading to delayed early gravitropic responses and altered root cone angles in adult plants.

Conclusions:

• DOCS1 is involved in root cap development and gravitropic responses throughout plant development.
• These findings provide new insights into the multifaceted functions of the DOCS1 gene in plants.