Essential Roles of the Linker Sequence Between Tetratricopeptide Repeat Motifs of Ethylene Overproduction 1 in Ethylene Biosynthesis

Abstract

Ethylene Overproduction 1 (ETO1) is a negative regulator of ethylene biosynthesis. However, the regulation mechanism of ETO1 remains largely unclear. Here, a novel eto1 allele (eto1-16) was isolated with typical triple phenotypes due to an amino acid substitution of G480C in the uncharacterized linker sequence between the TPR1 and TPR2 motifs. Further genetic and biochemical experiments confirmed the eto1-16 mutation site. Sequence analysis revealed that G480 is conserved not only in two paralogs, EOL1 and EOL2, in Arabidopsis, but also in the homologous protein in other species. The glycine mutations (eto1-11, eto1-12, and eto1-16) do not influence the mRNA abundance of ETO1, which is reflected by the mRNA secondary structure similar to that of WT. According to the protein-protein interaction analysis, the abnormal root phenotype of eto1-16 might be caused by the disruption of the interaction with type 2 1-aminocyclopropane-1-carboxylic acid (ACC) synthases (ACSs) proteins. Overall, these data suggest that the linker sequence between tetratricopeptide repeat (TPR) motifs and the glycine in TPR motifs or the linker region are essential for ETO1 to bind with downstream mediators, which strengthens our knowledge of ETO1 regulation in balancing ACSs.

A UPLC‐MS/MS method for quantification of metabolites in the ethylene biosynthesis pathway and its biological validation in Arabidopsis

“…This observation suggests functional redundancy among ACO genes in Arabidopsis , similar to what has been reported for the ACS gene family (Tsuchisaka et al ., 2009; Houben & Van De Poel, 2019). Previous studies have noted that the ethylene overproducing mutants eto1 and eto3 manifest phenotypic differences compared with WT exclusively in roots under light‐grown conditions (Rao et al ., 2002; Chen et al ., 2013; An & Gao, 2021). Correspondingly, our findings revealed that ACC accumulation in eto1 and eto3 as compared to WT was significant in roots, but not in shoots (Fig.…”

GLABROUS INFLORESCENCE STEMS3 binds to and activates RHD2 and RHD4 genes to promote root hair elongation in Arabidopsis

“…Ethylene biosynthesis is repressed by ETHYLENE OVERPRODUCTION1 ( ETO1 ) (An & Gao, 2021). The study found that eto1 root hair was longer, while auxin‐resistant mutants ibr5 , tir1 , and axr1 inhibited the longer root hair phenotype compared with eto1 (Strader et al., 2010).…”