# Genome-Wide Analysis of the YUCCA Gene Family in Wheat and the Potential Roles of TaYUCCA19 and Its Homologs in Male Reproductive Development

## TL;DR

This study explores the YUCCA gene family in wheat and identifies key genes involved in male reproductive development.

## Contribution

The study provides the first functional evidence of TaYUCCA genes in wheat male fertility.

## Key findings

- 64 TaYUCCA genes were identified and classified into three conserved clades.
- TaYUCCA19 is crucial for normal pollen development, as its silencing causes pollen abnormalities and reduced seed set.
- Gene expansion in the YUCCA family was driven by segmental and tandem duplication events.

## Abstract

YUCCA belongs to the flavin-containing monooxygenas and catalyzes the rate-limiting step in endogenous auxin biosynthesis, thereby regulating local auxin homeostasis and participating in diverse aspects of plant growth, development, and physiological processes. However, the relationship between the YUCCA genes and male fertility regulation in wheat remains unclear. In this study, we identified 64 TaYUCCA genes through whole-genome analysis and classified them into three clades, each of which is conserved in motif composition and gene structure. A synteny analysis indicated that family expansion was primarily driven by segmental duplication and tandem duplication, and Ka/Ks analysis suggested that all members are under purifying selection. An analysis of the expression patterns showed that the TaYUCCA genes displayed differential expression across various tissues and reproductive developmental stages. In the temperature-sensitive male-sterile wheat line YS3038, TaYUCCA19, TaYUCCA22, and TaYUCCA25 were specifically highly expressed at the uninucleate pollen stage under fertile conditions. The silencing of TaYUCCA19 resulted in abnormal pollen morphology and a significant reduction in the seed set rate, indicating that it is a key gene required for normal pollen development in wheat. Overall, this study systematically characterizes the wheat YUCCA gene family and provides the first functional evidence of TaYUCCA genes in male reproductive development, offering an important foundation for studies on wheat male sterility mechanisms and the exploitation of heterosis.