Four receptor-like cytoplasmic kinases regulate development and immunity in rice

Area of Science:

• Plant molecular biology
• Plant signaling pathways
• Plant immunity

Background:

• Receptor-like cytoplasmic kinases (RLCKs) are a large protein family in plants, but many remain uncharacterized.
• Understanding RLCK functions is crucial for deciphering plant growth and defense mechanisms.

Purpose of the Study:

• To functionally characterize four rice RLCKs (OsRLCK57, OsRLCK107, OsRLCK118, OsRLCK176) from subfamily VII.
• To investigate their roles in brassinosteroid (BR) signaling and plant immunity.

Main Methods:

• Yeast two-hybrid assays to examine protein interactions.
• Generation of transgenic rice lines with silenced RLCK genes.
• Phenotypic analysis of transgenic lines, including leaf angle, brassinolide sensitivity, tillering, and seed production.
• Assessment of XA21 gene expression and XA21-mediated immunity.

Main Results:

• The studied OsRLCKs interact with the rice brassinosteroid receptor OsBRI1.
• Silencing these OsRLCKs resulted in enlarged leaf angles and brassinolide hypersensitivity.
• Reduced tillering, panicle branching, and seed production were observed in specific silenced lines.
• Silencing decreased XA21 expression and compromised immunity against Xanthomonas oryzae pv. oryzae.

Conclusions:

• These OsRLCKs act as negative regulators of BR signaling.
• They function as positive regulators of immune responses by promoting XA21 expression.
• The findings reveal a dual role for these RLCKs in balancing plant growth and defense.