Genome-wide identification and functional characterization of LEA genes during seed development process in linseed flax (Linum usitatissimum L.)

Zhen Li,Hui Chi,Lida Han,Liang Li,Xinwu Pei,Tianbao Zhang,Yan Long,Caiyue Liu

doi:10.1186/s12870-021-02972-0

Zhen Li, Hui Chi + Show 6 more

Open Access

https://doi.org/10.1186/s12870-021-02972-0

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Abstract

BackgroundLEA proteins are widely distributed in the plant and animal kingdoms, as well as in micro-organisms. LEA genes make up a large family and function in plant protection against a variety of adverse conditions.ResultsBioinformatics approaches were adopted to identify LEA genes in the flax genome. In total, we found 50 LEA genes in the genome. We also conducted analyses of the physicochemical parameters and subcellular location of the genes and generated a phylogenetic tree. LuLEA genes were unevenly mapped among 15 flax chromosomes and 90% of the genes had less than two introns. Expression profiles of LuLEA showed that most LuLEA genes were expressed at a late stage of seed development. Functionally, the LuLEA1 gene reduced seed size and fatty acid contents in LuLEA1-overexpressed transgenic Arabidopsis lines.ConclusionOur study adds valuable knowledge about LEA genes in flax which can be used to improve related genes of seed development.

Highlights

Late embryogenesis abundant (LEA) proteins are widely distributed in the plant and animal kingdoms, as well as in micro-organisms
Based on the sequence homology and conserved motifs in the Pfam database, these LuLEA genes were divided into eight subfamilies, the LuLEA_1, LuLEA_2, LuLEA_3, LuLEA_4, LuLEA_5, LuLEA_6, dehydrin, and seed maturation protein (SMP) subfamilies
Past studies have shown that LEA genes participate in the regulatory network of seed development [18], we investigated the phenotypes of seeds produced from LuLEA1-overexpressing transgenic Arabidopsis

Summary

Results

Identification of LuLEA gene families in the flax genome Combining the methods of local BLAST with HMM, 50 LuLEA gene members of the LEA family were identified the flax genome (Table 1). Biological evolution and gene structure analysis of LuLEA genes To investigate the homology and similarity for the identified LuLEA genes, an unrooted phylogenetic tree was constructed based on the alignment of all LuLEA protein sequences (Fig. 1). Worth noting is that LuLEA17, which grouped into the LuLEA_2 subfamily, had the longest length than any other gene, up to 14 kb, and it had the largest number of introns (4) and exons (5). LuLEA1 is responsible for seed development and fatty acid metabolism Two independent overexpression lines, named LuLEA1– 6 and LuLEA1–7, were generated and analyzed. Total average fatty acid contents of the two overexpression lines were less than that of WT, Fig. 2 The distribution of exons and introns in LuLEA genes. These results suggest that LuLEA1 may block the process of transformations of C18:1 and C18:2 into C18:3 and C20:1 (Figs. 5d-f)

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