Phenylalanine ammonia-lyase family is closely associated with response to phosphate deficiency in rice.

Background: Phenylalanine ammonia-lyase (PAL) catalyzes the first step in the biosynthetic phenylpropanoid pathway (PPP) via deamination of phenylalanine to trans-cinnamic acid, a precursor for the lignin and flavonoid biosynthetic pathways. Although its role is well-established in various plants, the functional significance of PAL genes in rice remains poorly understood.

Objective: This study aims to find out the global feature of rice PAL genes associated with phosphate use efficiency.

Methods: To identify the biological functions of individual rice PAL genes, we performed meta-expression profiling analysis based on phylogenomics of rice PAL genes and confirmed the expression patterns using Quantitative real-time PCR (qPCR).

Results: We identified nine genes that were remarkably up-regulated during long-term phosphate (Pi) starvation and recovery processes through RNA-Seq data analysis. Expression patterns of the nine rice PAL genes under Pi starvation were further confirmed by qPCR, indicating that the function of PAL genes is strongly associated with Pi starvation response in rice.

Conclusion: Our study reports the functional significance of rice PAL genes involved in adaptation to low Pi growth conditions and provides useful information to improve Pi use efficiency in crop plant.