A Lipid-Anchored NAC Transcription Factor Is Translocated into the Nucleus and Activates Glyoxalase I Expression during Drought Stress

Abstract

The plant-specific NAC (NAM, ATAF1/2, and CUC2) transcription factors (TFs) play a vital role in the response to drought stress. Here, we report a lipid-anchored NACsa TF in Medicago falcata. MfNACsa is an essential regulator of plant tolerance to drought stress, resulting in the differential expression of genes involved in oxidation reduction and lipid transport and localization. MfNACsa is associated with membranes under unstressed conditions and, more specifically, is targeted to the plasma membrane through S-palmitoylation. However, a Cys 26 -to-Ser mutation or inhibition of S-palmitoylation results in MfNACsa retention in the endoplasmic reticulum/Golgi. Under drought stress, MfNACsa translocates to the nucleus through de-S-palmitoylation mediated by the thioesterase MtAPT1, as coexpression of APT1 results in the nuclear translocation of MfNACsa, whereas mutation of the catalytic site of APT1 results in colocalization with MfNACsa and membrane retention of MfNACsa. Specifically, the nuclear MfNACsa binds the glyoxalase I (MtGlyl) promoter under drought stress, resulting in drought tolerance by maintaining the glutathione pool in a reduced state, and the process is dependent on the APT1-NACsa regulatory module. Our findings reveal a novel mechanism for the nuclear translocation of an S-palmitoylated NAC in response to stress.

Genome‐wide analysis of flanking sequences reveals that Tnt1 insertion is positively correlated with gene methylation in Medicago truncatula

“…knockout or over‐expression) often drastically affects plant phenotypes (Riano‐Pachon et al ., ). Through forward genetics screenings, several M. truncatula developmental defects involving nodules, roots, leaves and flowers have been identified and, in many cases, the causative Tnt1 is inserted in a gene encoding a TF (Wang et al ., ; Chen et al ., ; Tadege et al ., ; Zhou et al ., , ; Cheng et al ., ; Couzigou et al ., ; Pislariu et al ., ; Uppalapati et al ., ; Verdier et al ., ; Niu et al ., ; Cerri et al ., ; Duan et al ., ; Gou et al ., ). To evaluate how many TFs are disrupted by Tnt1 insertions in M. truncatula Tnt1 insertion population, we downloaded M. truncatula TFs from the Plant Transcription Factor database (PlantTFDB).…”

Medicago falcata MfSTMIR, an E3 ligase of endoplasmic reticulum‐associated degradation, is involved in salt stress response

“…As a mock for the Tm treatment, an equivalent volume of DMSO was used in the same experimental procedure. The transcript levels of MtBiP1/2 and MtBIP3 in three biological replicates were quantified using qRT‐PCR using a CFX96 Real‐Time PCR Detection System (Bio‐Rad, Berkeley, CA, USA) and the 2 −ΔΔCT method, and Mtactin was used as an endogenous control (Duan et al ., ).…”

Transcriptional Factors Regulate Plant Stress Responses Through Mediating Secondary Metabolism

“…In addition, glutathione is a prototypic anti-oxidative metabolite that functionally eliminates the harmful effects of drought produced ROS [127]. MfNACsa in Medicago falcate was responsive for defending drought stress by regulating the gene expression of glyoxalase 1 to maintain glutathione level [110].…”