Arabidopsis thaliana Mutant with T-DNA Insertion in the Flot1 (At5g25250) Gene Promotor Possesses Increased Resistance to NaCl

Involvement of the Membrane Nanodomain Protein, AtFlot1, in Vesicular Transport of Plasma Membrane H+-ATPase in Arabidopsis thaliana under Salt Stress

“…In summary, the phenotypes of Atflot1 mutant plant lines described in this study and earlier [ 20 ] under salt stress conditions, together with the results obtained by the other groups [ 16 , 18 , 39 ], suggest that none of the At Flot isoforms play an exclusive role in the adaptation of A. thaliana to all tested abiotic stresses, including salinity. The explanation may be the multiplicity of vesicular protein transport pathways and the ability of the Atflot1ko knockout mutant to switch to alternative pathways that ensure proper delivery of proteins to the respective membranes.…”

“…At the same time, as shown by the results of our previous work [ 20 ], elevated expression of AtFlot1 in root cells of the Atflot1oe mutant led to a noticeable stimulation of growth, an increase in K + content, and a decrease in Na + content in the organs of this mutant during salinity stress, indicating the importance of the At Flot1 protein for the proper growth of A. thaliana and maintenance of ion homeostasis in its cells under these conditions. It is well known that the phenotype observed upon overexpression of a target protein may reflect the authentic biological role played by this protein [ 46 ] and, thus, the involvement of the At Flot1 protein in salt tolerance is supported by previous and current findings.…”

“…In general, the results outlined above as well obtained previously [ 20 ] testify in favor of the involvement of At Flot1, the membrane nanodomain protein, in various pathways of vesicular transport in A. thaliana , including exocytosis, endocytosis, and the pathway that delivers the substances into the vacuole through PMB biogenesis and the subsequent formation of PMBDs. It is most likely that At Flot1 is simultaneously required for several stages of each transport pathway, which is consistent with the idea that flotillins play structural rather than functional roles.…”

“…It is also worth noting that re-analysis of the Atflot1 sequencing data indicated that the T-DNA insert in Atflot1oe mutant line used by us earlier [ 20 ] is located at position −91 bp rather than at position −41 bp from the transcription start site, and the last 4 nucleotides 5′GCGC3′ of the left T-DNA border (LB) sequence have been replaced by a 10-nucleotide sequence 5′ATTGGTAATC3′.…”

“…The At Flot2 was binding to CPA2, a monovalent cation transporter, and all three At Flot isoforms interacted with cornichon [ 16 ], an A. thaliana protein of unknown function, an orthologue of which forms a complex with the K + /Na + transporter in rice [ 19 ]. In an A. thaliana mutant with a T-DNA insertion in the AtFlot1 gene promoter, which is characterized by increased expression of this gene, a higher content of K + and a lower content of Na + were found under salt stress when compared with wild type (WT) plants [ 20 ]. This mutant also developed organs with higher mass than WT when plants were grown under salt stress.…”