Vitronectin-like protein is a first line of defense against lanthanum (III) stress in Arabidopsis leaf cells

• VN is a first line in plant to defense against La(III) stress.
• La(III) rises the expression of VN and makes VN migrate to the plasma membrane.
• La(III) could coordinately bond to an O atom in VN to form La(III)-VN complexes.

Plants can uptake and accumulate rare earth elements (REEs) from the ecosystem. Responses of plants to REEs have attracted researchers’ attention for nearly one hundred years, but the mechanisms of their responses are largely unknown. Identifying the binding target of REEs and its mode of interaction with the target will be the key to reveal the cellular responsive mechanisms. In this study, La(III) as a representative of REEs, we found excitedly that vitronectin-like protein (VN) was strongly expressed in cells and migrated towards the plasma membrane with increasing concentrations of La(III), raising the possibility that VN acts as a defense mechanism to resist the entry of La(III) into cells. Interestingly, VN is an anchoring site and binding target for La(III) on the plasma membrane of Arabidopsis leaf cells. In this process, La(III) as a Lewis acid is anchored by VN as a Lewis base to form La(III)-VN coordination complexes. Therefore, VN is a first line of defense against La(III) stress and enhances plant tolerance to REEs. Our findings provide new insight into the cellular responsive mechanisms of plants to REEs.