Ion Homeostasis and Metabolome Analysis of Arabidopsis 14-3-3 Quadruple Mutants to Salt Stress

Abstract

Salinity is one of the major abiotic stresses that limits agricultural productivity worldwide. Many proteins with defined functions in salt stress adaptation are controlled through interactions with members of the 14-3-3 family. In the present study, we generated three 14-3-3 quadruple knockout mutants (qKOs: klpc, klun, and unpc) to study the role of six non-epsilon group 14-3-3 proteins for salt stress adaptation. The relative growth inhibition under 100 mM of NaCl stress was the same for wild-type (Wt) and qKOs, but the accumulation of Na+ in the shoots of klpc was significantly lower than that in Wt. This difference correlated with the higher expression of the HKT1 gene in klpc. Considering the regulatory role of 14-3-3 proteins in metabolism and the effect of salt stress on metabolite accumulation, we analyzed the effect of a 24-h salt treatment on the root metabolome of nutrient solution-grown genotypes. The results indicated that the klpc mutant had metabolome responses that were different from those of Wt. Notably, the reducing sugars, glucose and fructose, were lower in klpc under control and salt stress. On the other hand, their phosphorylated forms, glucose-6P and fructose-6P, were lower under salt stress as compared to Wt. This study provided insight into the functions of the 14-3-3 proteins from non-epsilon group members. In summary, it was found that these proteins control ion homeostasis and metabolite composition under salt stress conditions and non-stressed conditions. The analyses of single, double, and triple mutants that modify subsets from the most effective qKO mutant (klpc) may also reveal the potential redundancy for the observed phenotypes.

Genome-wide identification and characterization of 14-3-3 gene family related to negative regulation of starch accumulation in storage root of Manihot esculenta

“…The 14-3-3 protein plays a regulatory role in plant tricarboxylic acid cycle, glucose metabolism, shikimic acid synthesis, starch metabolism, root growth, and other physiological pathways by interacting with target proteins ( Swatek et al., 2011 ; Gao et al., 2014 ; Zhang et al., 2019 ; Gao et al., 2021 ). When the repression of six 14-3-3 genes from potatoes was downregulated, nitrate and carbon fixation key enzymes from transgenic potato plants were activated and accelerated starch accumulation in the storage roots of transgenic plants ( Żuk et al., 2003 ; Yu et al., 2016 ).…”

Mechanistic insights into the function of 14-3-3 proteins as negative regulators of brassinosteroid signaling in Arabidopsis

“…14-3-3s provide a conserved cup-shaped binding groove for phosphorylated protein ligands (Ballone et al, 2018). In plants, 14-3-3 proteins have been implicated in the regulation of cellular metabolism, ion and nutrient homeostasis (Ottmann et al, 2007;Denison et al, 2011;Xu et al, 2012;Yang et al, 2019;Gao et al, 2021aGao et al, , 2021bJiang et al, 2023), in plant immunity (Konagaya et al, 2004;Chang et al, 2009;Stanislas et al, 2009), and in different light and hormone signaling pathways (Sullivan et al, 2009;Sirichandra et al, 2010;Taoka et al, 2011;Tseng et al, 2012;Gao et al, 2014;Huang et al, 2018;Prado et al, 2019;Reuter et al, 2021;Waksman et al, 2023). 14-3-3 proteins have been previously reported to directly or indirectly associate with different BR signaling components including BRI1 and SERKs (Rienties et al, 2005;Karlova et al, 2006;Chang et al, 2009), BKI1 (Wang et al, 2011), BSU1 (Chang et al, 2009), BIN2 (Kim et al, 2023) and BZR1/BES1 (Gampala et al, 2007;Bai et al, 2007;Ryu et al, 2007Ryu et al, , 2010Wang et al, 2013).…”