Maize PPR278 Functions in Mitochondrial RNA Splicing and Editing

Area of Science:

• Plant Biology
• Molecular Biology
• Genetics

Background:

• Pentatricopeptide repeat (PPR) proteins are vital in plant development, particularly seed formation.
• While many PPR proteins function in mitochondria, some exhibit dual organelle localization, requiring further functional study.
• Limited functional characterization exists for maize (Zea mays L.) PPR proteins with multi-organelle roles.

Purpose of the Study:

• To clone and functionally characterize a P-subfamily PPR protein, PPR278, in maize.
• To investigate the role of PPR278 in seed development and its subcellular localization.
• To determine PPR278's involvement in mitochondrial gene expression processes.

Main Methods:

• Cloning and functional analysis of the PPR278 gene in maize.
• Phenotypic analysis of ppr278 loss-function mutants, including germination rates and kernel morphology.
• Expression analysis across different maize tissues.
• Determination of PPR278's role in mitochondrial transcript splicing and RNA editing.
• Subcellular localization studies of PPR278.

Main Results:

• Loss-function of PPR278 resulted in reduced germination rates, seedling defects, and smaller kernels.
• PPR278 expression was detected in all examined tissues.
• PPR278 was found to be involved in splicing of mitochondrial nad2 and nad5 transcripts.
• PPR278 participates in C-to-U RNA editing of 10 mitochondrial transcripts.
• PPR278 localized to the nucleus.

Conclusions:

• PPR278 plays a significant role in maize seed development.
• The protein impacts seed development by regulating mitochondrial intron splicing and RNA editing.
• PPR278 may possess regulatory functions in the nucleus, contributing to developmental processes.