Recent duplications and rare structural variations revealed by comparative sequence analysis of low molecular weight glutenin subunits (LMW-GS) genes re-identified using LMWgsFinder in 26 genomes of the grass family.

Key message: LMWgs Finder developed by this study was used to re-identify the LMW-GS genes in a total of 26 genomes across the grass family and several important and novel findings were obtained. LMW-GS are one of the primary components of wheat (Triticum aestivum L.) seed storage proteins, which have an important impact on wheat end-use quality traits. Identifying LMW-GS genes accurately within wheat genomes has consistently presented a significant challenge. LMWgsFinder developed by this study was used to re-identify the LMW-GS genes in a total of 26 genomes of the grass family. Apart from six species, a total of 291 LMW-GS genes were identified. Except for the two versions of the TaCS (Triticum aestivum Chinese Spring) genome, only 38.13% (98/257) of the LMW-GS genes identified by LMWgsFinder were annotated in the coding sequence annotation files (provided by the sequencing research groups) of the remaining 18 genomes. EnSpm-like transposon activity mediated recent duplication or triplication of the same LMW-GS gene has been observed in 8 wheat species for the first time, indicating that the replication of LMW-GS genes has been ongoing alongside the evolution of wheat. Several cases of rare structural variations associated with the loss or acquisition of LMW-GS gene function have been discovered and experimentally verified. Twenty-one new LMW-GS genes were discovered in 15 species of Triticeae. The results of this study provide the first empirical support at the DNA level, with confirmed chromosomal localization information, for the widely accepted notion that LMW-GS genes undergo gene duplication during wheat evolution. Additionally, this study offers gene sequence resources and a wealth of valuable information for further research on LMW-GS gene function, molecular-assisted selection, gene aggregation breeding, and molecular design breeding.