Genome-wide identification and expression analysis of late embryogenesis abundant (LEA) genes reveal their potential roles in somatic embryogenesis in hybrid sweetgum (Liquidambar styraciflua × Liquidambar formosana).

Abstract

Late embryogenesis abundant (LEA) proteins are widely distributed in higher plants that play significant roles in embryonic development and abiotic stress response. Hybrid sweetgum is an important forest tree resource around the world, and somatic embryogenesis is an efficient way of reproduction and utilization. However, a systematic analysis of the LEA family genes in hybrid sweetgum is lacking, this is not conducive to the efficiency of its somatic embryogenesis. From the whole genome of the hybrid sweetgum, utilizing hidden Markov models, an identification of a total of 79 LEA genes was successfully conducted. They were classified into eight different groups based on their conserved domains and phylogenetic relationships, with the LsfLEA2 group of genes being the most abundant. The gene structure and sequence characteristics and chromosomal localization, as well as the physicochemical properties of LEA proteins were meticulously carried out. Analysis of the cis-acting elements shows that most of the LsfLEA genes are associated with light-responsive-elements. In addition, some genes are associated with biosynthetic pathways, such as abscisic acid response, growth hormone response, methyl jasmonate response, somatic embryogenesis, meristematic tissue expression. Furthermore, we systematically analyzed the expression patterns of hybrid sweetgum LEA genes in different stages of somatic embryogenesis and different tissues, in LEA family genes we also found significant specificity in gene expression during somatic embryogenesis. This study provides new insights into the formation of members of the LsfLEA family genes in hybrid sweetgum, while improving the understanding of the potential role of these genes in the process of hybrid sweetgum somatic embryogenesis and abiotic stress response. These results have a certain guiding significance for the future functional study of LsfLEA family genes, and provide a theoretical basis for exploring the regulatory mechanism of LsfLEA genes in the somatic embryo development stage of hybrid sweetgum.