The STT3a subunit isoform of the Arabidopsis oligosaccharyltransferase controls adaptive responses to salt/osmotic stress.

Arabidopsis stt3a-1 and stt3a-2 mutations cause NaCl/osmotic sensitivity that is characterized by reduced cell division in the root meristem. Sequence comparison of the STT3a gene identified a yeast ortholog, STT3, which encodes an essential subunit of the oligosaccharyltransferase complex that is involved in protein N-glycosylation. NaCl induces the unfolded protein response in the endoplasmic reticulum (ER) and cell cycle arrest in root tip cells of stt3a seedlings, as determined by expression profiling of ER stress-responsive chaperone (BiP-GUS) and cell division (CycB1;1-GUS) genes, respectively.

C-terminal domain phosphatase-like family members (AtCPLs) differentially regulate Arabidopsis thaliana abiotic stress signaling, growth, and development.

Cold, hyperosmolarity, and abscisic acid (ABA) signaling induce RD29A expression, which is an indicator of the plant stress adaptation response. Two nonallelic Arabidopsis thaliana (ecotype C24) T-DNA insertional mutations, cpl1 and cpl3, were identified based on hyperinduction of RD29A expression that was monitored by using the luciferase (LUC) reporter gene (RD29ALUC) imaging system. Genetic linkage analysis and complementation data established that the recessive cpl1 and cpl3 mutations are caused by T-DNA insertions in AtCPL1 (Arabidopsis C-terminal domain phosphatase-like) and AtCPL3, respectively.

The ascorbic acid cycle mediates signal transduction leading to stress-induced stomatal closure.

Using a combination of pharmacological approaches, mutation analysis and a gene silencing strategy, we present evidence that treatment of tomato (Lycopersicon esculentum Mill.) plants with exogenous ascorbate (AsA) subsequently increases the level of cellular AsA and causes stomatal closure. Using the ABA-deficient mutants flacca and sitiens, we show that the AsA-mediated induction of stomatal closure requires the participation of ABA.