Overexpression of a miR393-Resistant Form of Transport Inhibitor Response Protein 1 (mTIR1) Enhances Salt Tolerance by Increased Osmoregulation and Na+ Exclusion in Arabidopsis thaliana

Abstract

Soil salinity is a common environmental stress factor that limits agricultural production worldwide. Plants have evolved different strategies to achieve salt tolerance. miR393 has been identified as closely related to biotic and abiotic stresses, and targets F-box genes that encode auxin receptors. The miR393-TIR1/AFB2/AFB3 regulatory module was discovered to have multiple functions that manipulate the auxin response. This study focused on miR393 and one of its targets, TIR1, and found that they played potential roles in response to salt stress. Our results showed that overexpression of a miR393-resistant TIR1 gene (mTIR1) in Arabidopsis clearly enhanced salt stress tolerance, which led to a higher germination rate, less water loss, reduced inhibition of root elongation, delayed senescence, decreased death rate and stabilized Chl content. These plants accumulated more proline and anthocyanin, and displayed enhanced osmotic stress tolerance. The expression of some salt stress-related genes was altered, and sodium content can be reduced in these plants under salt stress. We proposed that highly increased auxin signaling by overexpression of mTIR1 may trigger auxin-mediated downstream pathways to enhance plant salt stress resistance by osmoregulation and increased Na(+) exclusion.

Transgenic creeping bentgrass overexpressing Osa‐miR393a exhibits altered plant development and improved multiple stress tolerance

“…Previous studies demonstrated that miR393 is involved in plant responses to drought, salt stresses and auxin treatment in annual species (Chen et al ., , ; Gao et al ., ; Xia et al ., ). In this study, we investigated its role in perennial grass species, creeping bentgrass.…”

“…Next, we quantitatively analysed miR393 expression in response to salt, drought, and heat stresses and IAA treatment in leaves. Mature miR393 was found to be significantly induced by these abiotic stressors and auxin treatment (Figure S1b–e), in agreement with observations in Arabidopsis and rice (Chen et al ., , ; Gao et al ., ; Xia et al ., ), suggesting that miR393 is also regulated by various abiotic stresses and hormone auxin in creeping bentgrass.…”

Identification of Submergence-Responsive MicroRNAs and Their Targets Reveals Complex MiRNA-Mediated Regulatory Networks in Lotus (Nelumbo nucifera Gaertn)

“…miR393 has been identified as closely related to biotic and abiotic stresses and was found to target TIR1 genes in this work. TIR1 has been shown to have a role in enhancing plant stress tolerance (Chen et al, 2015). The down-regulation of NNU_ghr-miR393, NNU_gma-miR393h, and NNU_ata-miR393-5p resulted in increased expression level of TIR1 genes.…”

New insights into the roles of cucumber TIR1 homologs and miR393 in regulating fruit/seed set development and leaf morphogenesis

“…Downregulation of OsTIR1 and OsAFB2 via OsmiR393 led to reduced tolerance to salt and drought in rice [40]. In contrast, overexpression of a miR393-resistant form of mTIR1 enhanced salt tolerance in Arabidopsis [41]. However, less is known about the role of the miR393/TIR1 homolog module in the stages of fruit development.…”