The late embryogenesis abundant (LEA) genes are mainly expressed in seeds and, as its name suggests, are accumulated during late embryo development stage. The LEA genes often exist as a large gene family in higher plants. Previously, the functional expression screening of LEA proteins in vivo in yeast or E. coli under abiotic stresses have been investigated in various flowering plant species. However, no gymnosperm LEA genes have been screened ever before.
Dr. GAO Jie of Xishuangbanna Tropical Botanical Garden (XTBG) and her collaborator from Institute of Botany conducted a study to examine the evolutionary and functional diversity of the LEA gene family in Pinus tabuliformis, a dominant conifer species widely distributed over mountainous areas from northern to central China. They integrated phylogenetic analysis, protein motif structure, gene expression and heterologous expression analysis in E. coli of 23 full-length LEA genes.
The researchers have cloned 23 genes from the P. tabuliformis genome belonging to seven groups of the LEA gene family. To get a better understanding of the expression pattern of P.tabuliformis LEA genes, they collected five different tissues/organs (root, phloem, needle, bud and two weeks germinant) and analyzed them by using RT-PCR to detect the transcription abundance. They selected 13 genes to construct the recombinant BL/LEA to do the heat and salt treatment to determine the function of expressed LEA fusion protein in stress conditions.
The study found that the expressed P. tabuliformis LEA fusion polypeptide conferred salt and heat tolerance to the host cells. Some of the groups showed an increased resistance to heat and salt. Some of the groups showed responses to both heat and salt stresses, but genes within group showed different patterns. The protein sequence identified among groups was much lower than the values within each group which exhibited a high degree of divergence among the protein groups.
The study confirmed that the P. tabuliformis LEA proteins from all LEA subgroups enhanced tolerance to elevated salt and heat conditions. It indicated that the LEA genes had a wider repertoire of roles in stress responses and may play a common role in plant acclimation to stress conditions.
The study entitled “Functional characterization of the late embryogenesis abundant (LEA) protein gene family from Pinus tabuliformis(Pinaceae) in Escherichia coli” has been published in Scientific Reports.
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