Arabidopsis thaliana NIP2;1 , a lactic acid transporter, is essential for plant survival during hypoxic stress

NIPs are nodulin-intrinsic proteins that are specific to plants and involved in transport of water and other uncharged solutes. Arabidopsis thaliana consists of nine NIPgenes.

In the current study, attention has been focused on NIP2;1(NIPsubgroup I), one of the representative Arabidopsis NIPs, in accordance with its cellular and subcellular localization, tissue, transport activity, and biological roles in Arabidopsis.

It has been shown in experiments that AtNIP2;1is especially responsive to hypoxia-induced stress. Hypoxia is a condition in which most of the oxygen has been removed from an environment. In hypoxic environments, plants construct a specific mechanism to cooperate with hypoxic conditions, such as increasing glycolytic flux to provide ATP, increase of fermentation metabolism, and induction of morphological and developmental changes. A functional analysis of AtNIP2;1has shown that AtNIP2;1transports lactic acid, and may play a role in adaptation to fermentation of lactic acid under anaerobic stress.

In this study, it is shown that Arabidopsis thalianaNIP2;1(AtNIP2;1)expression is explicitly stimulated through hypoxia. It is shown that knockout of NIP2;1genes are susceptible to hypoxic treatment. In the survival assay experiment, NIP2;1knockout plants had a significantly lower survival rate than the wild type plants. A metabolic analysis was performed on both the wild type and knockout lines after hypoxia.