Rice BIG gene is required for seedling viability

Area of Science:

• Plant Biology
• Molecular Genetics
• Biochemistry

Background:

• The Arabidopsis BIG (AtBIG) protein is essential for auxin transport, influencing plant architecture and environmental adaptability.
• A functional homolog of AtBIG in rice (OsBIG) has been identified but remains uncharacterized.

Purpose of the Study:

• To characterize the gene structure and elucidate the function of the rice OsBIG gene.
• To investigate the role of OsBIG in rice growth, development, and response to stimuli.

Main Methods:

• Sequence and phylogenetic analysis of OsBIG homologs across species.
• CRISPR/Cas9-mediated genome editing to create Osbig knockout rice plants.
• Phenotypic analysis of Osbig knockout plants, including cell death, electrolyte leakage, lipid peroxidation, and chlorophyll content assessment.
• RNA-sequencing (RNA-seq) to analyze gene expression changes in Osbig knockout versus wild-type plants.

Main Results:

• OsBIG homologs exhibit high amino acid conservation across species.
• Osbig knockout plants displayed severe phenotypes, including significant cell death, increased electrolyte leakage, membrane lipid peroxidation, and reduced chlorophyll content, leading to seedling lethality.
• RNA-seq analysis revealed significant perturbations in metabolic and hormonal pathways, including ribosome biogenesis, DNA replication, photosynthesis, and chlorophyll metabolism, in Osbig knockout plants.

Conclusions:

• The OsBIG gene is integral to normal growth and development in rice.
• OsBIG plays a critical role in maintaining cellular integrity, chlorophyll biosynthesis, and essential metabolic pathways in rice seedlings.