# Pan2‐Pan3 Complex‐Mediated Deadenylation Enforces mRNA Quality Control for Infection of the Rice Blast Fungus

## TL;DR

The Pan2-Pan3 complex in rice blast fungus controls mRNA quality, which is crucial for infection, by trimming RNA tails and regulating key genes for virulence.

## Contribution

Discovery that deadenylation, not transcription, controls developmental timing in a plant pathogen.

## Key findings

- Pan2-Pan3 complex trims mRNA tails in P-bodies to enforce quality control in the rice blast fungus.
- Loss of Pan2-Pan3 causes virulence loss due to stalled infection structures and impaired autophagy.
- Key genes like ATG5, GLS2, and DES1 are destabilized without deadenylation, crippling infection.

## Abstract

Poly(A) tail shortening by deadenylases is a central checkpoint linking mRNA fate to eukaryotic development, yet its impact on fungal pathogenesis remains unexplored. Here, we uncover that the Pan2‐Pan3 deadenylase complex is a master regulator of infection in the rice blast fungus Magnaporthe oryzae. Pan2 and Pan3 form a catalytically active complex that localizes to P‐bodies and globally trims poly(A) tails to enforce mRNA quality control. Deletion of either or both subunits abolishes this quality‐control checkpoint, causing severe virulence loss due to arrested appressorium maturation, disrupted glycogen/lipid mobilization, and impaired autophagy. Integrating poly(A)‐seq and transcriptome profiling reveals 390 mRNAs whose poly(A) tails are ≥ 5 nt longer and whose steady‐state levels are elevated in the Δpan2Δpan3 mutant; among them, ATG5, GLS2, and DES1—key genes governing autophagy, ER quality control, and ROS detoxification respectively—are directly deadenylated by Pan2‐Pan3. Loss of deadenylation destabilizes these mRNAs and reduces their protein output, thereby crippling infection. Our findings establish Pan2‐Pan3 complex‐mediated deadenylation as an essential post‐transcriptional layer that orchestrates fungal virulence through stringent mRNA quality control, offering a novel target for crop protection.

Discovery that deadenylation, rather than transcription, acts as the rate‐limiting step for developmental timing in a plant pathogen. Evidence that P‐body integrity and mRNA decay are mechanistically coupled to rapid cellular differentiation under environmental stress. Identification of Pan2‐Pan3 as a pathogen‐specific “meta‐virulence factor” absent in plants, offering a highly specific target for sustainable crop protection.