Rice phosphate transporter reduces the low phosphate response through jasmonate signaling.

Area of Science:

• Plant Biology
• Molecular Genetics
• Biochemistry

Background:

• Phosphorus (P) is vital for plant growth, with deficiency limiting crop yields.
• The PHOSPHATE1 (PHO1) protein family, including rice OsPHO1;2, is crucial for phosphate (Pi) transport from roots to shoots.
• OsPHO1;2 loss-of-function mutants show severe growth defects and Pi deficiency even with adequate external Pi.

Purpose of the Study:

• To investigate the functions of OsPHO1;2 domains beyond Pi transport.
• To understand the role of specific OsPHO1;2 domains in plant growth and signaling pathways.

Main Methods:

• Generated CRISPR/Cas9 rice lines expressing truncated OsPHO1;2 variants (S-EXS and T-EXS).
• Conducted phenotypic analyses under varying Pi conditions.
• Utilized transcriptome profiling to analyze gene expression changes.

Main Results:

• S-EXS lines showed improved growth and reduced jasmonic acid accumulation compared to mutants, despite similar shoot Pi levels.
• T-EXS lines exhibited growth defects similar to ospho1;2 mutants.
• Transcriptome data indicated suppressed defense and phosphate starvation responses in S-EXS lines.
• Both S-EXS and T-EXS lines retained seed development and phosphorus content defects.

Conclusions:

• The SPX-EXS (S-EXS) domain of OsPHO1;2 promotes plant growth independently of Pi transport.
• This domain modulates jasmonate signaling and suppresses phosphate starvation responses, indicating a signaling role.
• Findings provide insights into Pi homeostasis and potential breeding strategies for Pi-efficient crops.