Arabidopsis nucleoporin NUP96 mediates plant salt tolerance by modulating the transcription of salt-responsive genes.

ABSTRACT

MAIN CONCLUSION: Physiological and molecular tests show that NUP96 plays an important role in the plant response to salt stress, resulting from the reprogramming of transcriptomic profiles, which are likely to be mediated by the influence on the nuclear/cytosol shuttling of the key regulators of salt tolerance. As a key component of the nuclear pore complex (NPC), nucleoporin 96 (NUP96) is critical for modulating plant development and interactions with environmental factors, but whether NUP96 is involved in the salt response is still unknown. Here, we analyzed the role of Arabidopsis NUP96 under salt stress. The loss-of-function mutant nup96 exhibited salt sensitivity in terms of rosette growth and root elongation, and showed attenuated capacity in maintaining ion and ROS homeostasis, which could be compensated for by the overexpression of NUP96. RNA sequencing revealed that many salt-responsive genes were misregulated after NUP96 mutation, and especially NUP96 is required for the expression of a large portion of salt-induced genes. This is likely correlated with the activity in facilitating nuclear/cytosol transport of the underlying regulators in salt tolerance such as the transcription factor ATAP2, targeted by eight downregulated genes in nup96 under salt stress. Our results illustrate that NUP96 plays an important role in the salt response, probably by regulating the nucleocytoplasmic shuttling of key mRNAs or proteins associated with plant salt responsiveness.