Importin-β From the Recretohalophyte Enhances Salt Tolerance in by Reducing Root Hair Development and Abscisic Acid Sensitivity.

Aims: To elucidate the genetics underlying salt tolerance in recretohalophytes and assess its relevance to non-halophytes, we cloned the homolog of (Arabidopsis) () and named it , an importin-β gene associated with trichome initiation and reduced abscisic acid (ABA) sensitivity, and then we assessed the heterologously expressed in Arabidopsis.

Methods: We examined expression and assessed the effect of heterologous expression in Arabidopsis on root hair/trichome induction; the expression levels of possible related genes in trichome/root hair development; some physiological parameters involved in salt tolerance including germination rate, root length, and contents of Na, proline, and malondialdehyde; and the response of ABA at the germination stage.

Results: The gene is highly expressed in the salt gland development stage and salt treatment, especially located in the salt gland by hybridization, and the LbSAD2 protein contains some special domains compared with AtSAD2, which may suggest the involvement of LbSAD2 in salt tolerance. Compared with the mutant CS65878, which lacks trichomes, had higher trichome abundance but lower root hair abundance. Under 100 mM NaCl treatment, showed enhanced germination and root lengths; improved physiological parameters, including high proline and low contents of Na and malondialdehyde; higher expression of the salt-tolerance genes Δ () and (); reduced ABA sensitivity; and increased expression of the ABA signaling genes () and (), but not of the ABA biosynthesis gene ().

Conclusion: enhances salt tolerance in Arabidopsis by specifically reducing root hair development, Na accumulation, and ABA sensitivity.