Transcriptomic Profiling of Arabidopsis thaliana Mutant pad2.1 in Response to Combined Cold and Osmotic Stress

Abstract

The contribution of glutathione (GSH) in stress tolerance, defense response and antioxidant signaling is an established fact. In this study transcriptome analysis of pad2.1, an Arabidopsis thaliana mutant, after combined osmotic and cold stress treatment has been performed to explore the intricate position of GSH in the stress and defense signaling network in planta. Microarray data revealed the differential regulation of about 1674 genes in pad2.1 amongst which 973 and 701 were significantly up- and down-regulated respectively. Gene enrichment, functional pathway analysis by DAVID and MapMan analysis identified various stress and defense related genes viz. members of heat shock protein family, peptidyl prolyl isomerase (PPIase), thioredoxin peroxidase (TPX2), glutathione-S-transferase (GST), NBS-LRR type resistance protein etc. as down-regulated. The expression pattern of the above mentioned stress and defense related genes and APETALA were also validated by comparative proteomic analysis of combined stress treated Col-0 and pad2.1. Functional annotation noted down-regulation of UDP-glycosyl transferase, 4-coumarate CoA ligase 8, cinnamyl alcohol dehydrogenase 4 (CAD4), ACC synthase and ACC oxidase which are the important enzymes of phenylpropanoid, lignin and ethylene (ET) biosynthetic pathway respectively. Since the only difference between Col-0 (Wild type) and pad2.1 is the content of GSH, so, this study suggested that in addition to its association with specific stress responsive genes and proteins, GSH provides tolerance to plants by its involvement with phenylpropanoid, lignin and ET biosynthesis under stress conditions.

The Agrobacterium F-Box Protein Effector VirF Destabilizes the Arabidopsis GLABROUS1 Enhancer/Binding Protein-Like Transcription Factor VFP4, a Transcriptional Activator of Defense Response Genes

“…As an approach to identify these factors, we assessed the global effects of VFP4 loss-of-function on the transcription of defense response genes, using RNA-seq analysis of the RNA samples characterized in Figure 6A. The resulting data were analyzed by MapMan, an ontology technique designed to analyze plant-specific transcriptional profiles in a variety of species, including Arabidopsis (Johnston et al 2014; Kumar et al 2015; Rotter et al 2007; Urbanczyk-Wochniak et al 2006). We used DESeq (Anders and Huber 2010) to identify differentially expressed genes (DEGs) and found statistically significant changes in the expression of 479 genes between wild-type Col-0 and the vfp4-1 loss-of-function line (false discovery rate [FDR] < 0.001 and log 2 fold change [FC] > 2) (Supplementary Table S1).…”

Changes in the proteome of pad2-1, a glutathione depleted Arabidopsis mutant, during Pseudomonas syringae infection

“…Very recently, we have reported that the mutant is also susceptible to combined osmotic and cold stress treatments. Microarray analysis identified that stress-mediated up-regulation of the lignin, phenylpropanoid and ethylene biosynthetic pathway genes were impaired in the pad2-1 mutant [19].…”

“…Recently, the pad2-1 mutant has also been reported to exhibit vulnerability to combined osmotic and cold stress. Transcript analysis has revealed that GSH provides resistance against this combined stress by modulating phenylpropanoid, lignin and ethylene biosynthetic pathways [19]. The enzymes of GSH synthesis and metabolism are reported to be induced in response to stress [20].…”

Hormone signaling pathways under stress combinations

“…Transcripts responsive to hormones such as auxin, ethylene, brassinosteroid and ABA were differentially expressed in pad2.1 mutant compared to WT plants under the osmotic and cold stress combination. 39 Transcripts involved in ethylene synthesis were down-regulated in pad2.1 mutants. The alteration of these transcripts might be due to the increase in ROS by GSH deficiency, or indicating the possibility that GSH might regulate genes and protein expression by thiol mediated modification of various regulatory proteins.…”

“…The models were generated based on the researches using Arabidopsis subjected to different stress combinations. 15,[36][37][38][39] A model of the signaling pathway under the drought and UV-B combination was also suggested in a recent review 35 based the researches using different plant species. ABA; abscisic acid, AUX; auxin, BR; brassinosteroid, ET; ethylene, JA; jasmonic acid, SA; salicylic acid.…”