# Modulating Purothionin Accumulation and Signal Peptide Cleavage Fine‐Tunes Wheat Flour Gluten Properties to Improve Cookie‐Making Quality

## TL;DR

A wheat mutant with reduced gluten improves cookie quality by weakening gluten networks through altered protein processing.

## Contribution

A dual genetic strategy is proposed to modulate gluten properties by targeting signal peptide cleavage and purothionin expression.

## Key findings

- The lgp2 mutation reduces gluten content and weakens gluten networks, improving cookie-making performance.
- LGP2 encodes alpha-2-purothionin, which interacts with seed storage proteins to influence gluten formation.
- Knockdown and overexpression studies confirm LGP2's role in gluten quantity and quality.

## Abstract

In contrast to many wheat (Triticum aestivum)‐based products that benefit from strong gluten development, cookies benefit from weaker gluten. However, the development of wheat varieties that produce flour optimal for cookie making remains limited. In this study, we identified the wheat mutant low gluten protein 2 (lgp2), with reduced gluten content and a weakened gluten network, that significantly improved several aspects of cookie‐making performance. The lgp2 phenotype is caused by a missense mutation in LGP2 that affects the signal peptide cleavage site of the encoded protein. Map‐based cloning reveals that LGP2 encodes alpha‐2‐purothionin, a member of the thionin family of small proteins with potential antimicrobial activity. The lgp2 mutation leads to endoplasmic reticulum stress, abnormal protein body formation, and disrupted gluten development. Additionally, alpha‐2‐purothionin interacts with key seed storage proteins, contributing to gluten formation. Knockdown and overexpression studies confirmed that LGP2 affects gluten quantity and quality. Based on these findings, we propose dual genetic strategies targeting signal peptide processing and modulating LGP2 expression to fine‐tune gluten properties for improved cookie quality. The lgp2 allele offers great potential for breeding low‐gluten wheat varieties tailored for the production of cookies and other specialty food products.

Dual genetic strategies for improving wheat processing quality by regulating purothionin accumulation to modulate gluten quantity and quality. The first strategy involves targeting signal peptide (SP) cleavage sites (e.g., through mutation) to indirectly reduce gluten content, thereby disrupting gluten network formation. The second strategy focuses on modulating purothionin gene expression (e.g., via knockdown or knockout) to fine‐tune both the quantity and quality of gluten.