The 30th International Conference on Arabidopsis Research (ICAR 2019)

746 / 2019-05-15 10:44:35

The zinc-finger protein SlZF3 from tomato improves Arabidopsis salt tolerance via regulating ascorbic acid pathway

ascorbic acid,zinc finger,salt tolerance,CSN5B,SlZF3

Plenary track > Abiotic Stress

The elimination of extra reactive oxygen species (ROS) produced under abiotic stress is critical important for plant stress tolerance. Ascorbic acid (AsA) serves as an ROS scavenger and thus plays important functions in plant stress tolerance. Plant AsA biosynthetic and metabolic pathways are well established, however, genes that regulate those pathways are less studied. In our study, we characterized a novel regulatory gene from tomato named SlZF3 that encodes a Cys2/His2-type zinc-finger protein with an EAR repression domain. The transcripts of SlZF3 were rapidly induced by NaCl treatments. Overexpression of SlZF3 in Arabidopsis increased the levels of AsA significantly. As expected, the AsA-mediated ROS scavenging capacity of the SlZF3-overexpressing plants was increased, and consequently, the salt tolerance of the transgenic plants was increased. Protein-protein interaction assays including Y2H, BiFC and Co-IP demonstrated that SlZF3 directly binds CSN5B, a key component of the COP9 signalosome. The agrobacterium infiltration-based transient assays based on luciferase reporter showed that SlZF3 and VTC1 (a GDP-Man pyrophosphorylase that serves a rate limiting enzyme in AsA biosynthesis) competitively bind to CSN5B. In additional, we found that the EAR domain promoted the stability of SlZF3 but was not required for the interaction between SlZF3 and CSN5B. Our findings showed that SlZF3 improves Arabidopsis salt tolerance though enhancing AsA biosynthesis.