ECT9 condensates with ECT1 and regulates plant immunity.

Area of Science:

• Plant immunity
• Molecular biology
• Biochemistry

Background:

• RNA binding proteins (RBPs) are crucial for regulating immune messenger RNAs (mRNAs) at multiple levels.
• RBPs often exist as families, necessitating mechanisms for coordinated function.

Purpose of the Study:

• To investigate the coordination of YTH protein family members in Arabidopsis immune responses.
• To determine if RNA binding proteins can form condensates to regulate plant immunity.

Main Methods:

• Screening of 13 YTH family members for condensate formation.
• In vivo and in vitro co-condensation assays between ECT9 and ECT1.
• Phenotypic analysis of single and double mutants (ect1, ect9, ect1/9) in response to pathogens.

Main Results:

• EVOLUTIONARILY CONSERVED C-TERMINAL REGION 9 (ECT9) forms salicylic acid (SA)-sensitive condensates.
• ECT1, unable to form condensates alone, is recruited to ECT9 condensates.
• The ect1/9 double mutant exhibits enhanced immune responses compared to single mutants.

Conclusions:

• Co-condensation between ECT9 and ECT1 is a mechanism for regulating plant immune responses.
• This study reveals a novel role for RBP co-condensation in conferring redundant functions within protein families.