A novel gene LbHLH from the halophyte Limonium bicolor enhances salt tolerance via alleviating osmotic stress and reducing root hair development

Abstract

Background Identifying genes involved in salt tolerance in the recretohalophyte Limonium bicolor could facilitate the breeding of crops with enhanced salt tolerance. Here we cloned the previously uncharacterized gene LbHLH and explored its role in salt tolerance. Results The 2,067-bp open reading frame of LbHLH encodes a 688-amino-acid protein with a typical helix-loop-helix (HLH) domain. In situ hybridization showed that LbHLH is expressed in salt glands of L. bicolor. LbHLH localizes to the nucleus, and LbHLH is highly expressed during salt gland development and in response to NaCl treatment. To further explore its function, we heterologously expressed LbHLH in Arabidopsis thaliana under the 35S promoter. The overexpression lines showed significantly increased trichome number and reduced root hair number. LbHLH might interact with GLABRA1 to influence trichome and root hair development, as revealed by yeast two-hybrid analysis. The transgenic lines showed higher germination percentages and longer roots than the wild type under NaCl treatment. Analysis of seedlings grown on medium containing mannitol with the same osmotic pressure as 100 mM NaCl or LiCl with the same ionic effect as 100 mM NaCl demonstrated that overexpressing LbHLH relieved osmotic stress. Conclusion These results indicate that LbHLH enhances salt tolerance by alleviating osmotic damage under NaCl stress.

Analysis on the salt tolerance of Nitraria sibirica Pall. based on Pacbio full-length transcriptome sequencing

“…Soil salinity seriously restricts agricultural production and ecological stability (Yang and Guo, 2018a). According to the statistics of the Food and Agriculture Organization (FAO) of the United Nations, the area of saline-alkali land in the world is as high as 9.54×10 8 hm 2 , accounting for more than 6.5% of the total land area in the world (Wang et al, 2021; Yang and Guo, 2018b). In China, the total area of saline soil exceeds 9.91×10 7 hm 2 , accounting for about 10% of the land area.…”