Arabidopsis Toxicos en Levadura 12 Modulates Salt Stress and ABA Responses in Arabidopsis thaliana

Salt is one of the most common abiotic stresses, causing ionic and osmotic pressure changes that affect plant growth and development. In this work, we present molecular and genetic evidence that Arabidopsis Toxicos en Levadura 12 (ATL12) is involved in both salt stress and in the abscisic acid response to this stress. We demonstrate that ATL12 is highly induced in response to salt stress and that atl12 mutants have a lower germination rate, decreased root length, and lower survival rate compared to the Col-0 wild-type in response to salt stress. Overexpression of ATL12 increases expression of the salt stress-associated genes SOS1/2, and ABA-responsive gene RD29B. Additionally, higher levels of reactive oxygen species are detected when ATL12 is overexpressed, and qRT-PCR showed that ATL12 is involved in the AtRBOHD/F-mediated signaling. ATL12 expression is also highly induced by ABA treatment. Mutants of atl12 are hypersensitive to ABA and have a shorter root length. A decrease in water loss and reduced stomatal aperture were also observed in atl12 mutants in response to ABA. ABA-responsive genes RD29B and RAB18 were downregulated in atl12 mutants but were upregulated in the overexpression line of ATL12 in response to ABA. Taken together our results suggest that ATL12 modulates the response to salt stress and is involved in the ABA signaling pathway in Arabidopsis thaliana.