Impacts of natural variations in the TaLEA-1A gene on seed dormancy and germination in wheat and transgenic Arabidopsis and rice

Late embryogenesis abundant (LEA) proteins play important roles in plant development and responses to diverse stresses. However, their specific roles in seed dormancy and germination remain unclear. In this study, we identified TaLEA-1A, an LEA gene highly expressed in wheat seeds and differentially expressed in imbibed seeds of weak-dormancy variety Jing 411 (J411) and strong-dormancy variety Hongmangchun 21 (HMC21). Sequence analyses revealed 14 variations in the promoter and coding regions of TaLEA-1A between J411 and HMC21. Subsequent validation established associations of a single nucleotide polymorphism (SNP) in the promoter (-1366 bp, G/A) and an insertion/deletion (Indel) variation in the coding region (+345 bp, -/C) with seed dormancy and germination across 192 wheat varieties. Furthermore, the effects of the strong-dormancy allele TaLEA-1A-345-ins and weak-dormancy allele TaLEA-1A-345-del on seed dormancy and germination were confirmed using transgenic Arabidopsis and rice lines as well as J411 mutant induced with ethyl methane sulphonate. Analyses of endogenous hormone contents and expression patterns suggested that TaLEA-1A may regulate seed dormancy and germination by mediating gibberellic acid and abscisic acid balance. These findings not only contribute to unraveling the intricate regulatory network governing seed dormancy and germination in wheat and other plants but also provide a favorable gene and molecular marker for genetic improvement of wheat PHS resistance.