No abstract

Microarray expression profile analysis is a useful approach to increase our knowledge about genes involved in regulatory networks and signal transduction pathways related to abiotic stress tolerance. Salt and drought, as two important abiotic stresses, adversely affect plant productivity in the world every year. To understand stress response mechanisms and identify genes and proteins which play critical roles in these mechanisms, the study of individual genes and proteins cannot be considered as an effective approach. On the other hand, the availability of new global data provides us an effective way to shed some light on the central role of molecules involved in stress response mechanisms in the plant. A meta-analysis of salt and drought stress responses was carried out using 38 samples of different experiments from leaves and roots of Arabidopsis plants exposed to drought and salt stresses. We figured out the number of differentially expressed genes (DEGs) was higher in roots under both stresses. Also, we found that the number of common DEGs under both stresses was more in roots and also the number of common DEGs in both tissues under salt stress was more than drought stress. The highest percent of DEGs was related to cell and cell part (about 87%). Around 9% and 7% of DEGs in roots and leaves encoded transcription factors, respectively. Network analysis revealed that three transcription factor families HSF, AP2/ERF and C2H2, may have critical roles in salt and drought stress response mechanisms in Arabidopsis ​and some proteins like STZ may be introduced as a new candidate gene for enhancing salt and drought tolerance in crop plants.

In order to identify loci controlling seedling morpho-physiologic characteristics in 88 bread wheat cultivars, a greenhouse experiment based on simple alpha lattice was conducted under both normal and 120 mM (12 ds/m) salt stress condition of the Faculty of Agriculture, Urmia University in 2020-2021 cropping season. Chlorophyll a, b and carotenoid content, proline, plant fresh and dry weight, plant height and leaf relative water content (RWC), Na + , K + and K + /Na + concentrations were measured. After genotyping by sequencing with Ion Torrent technology and removal of SNPs with more than 20% of missing data and minor allele frequency less than 5%, a total of 5869 SNP markers were identified. Based on association mapping with the mixed linear model (MLM) method, a total of 25 marker-trait associations were detected under normal conditions. The A and D genomes had the highest and lowest number of significant marker-trait associations (MTAs). Among the studied traits under normal conditions, chlorophyll a had the highest number of MTAs on 1A, 3B, 3D, 5B, 7A chromosomes with eight MTAs. A total of 21 MTAs were identified under salt stress conditions which the genome B and D had the highest and lowest number of MTAs, respectively. Five MTAs were identified for plant fresh weight, which were located on chromosomes 4A and 6B. The results of this study provide valuable information about the loci associated with the studied traits, which can be used in marker assisted selection in wheat breeding programs after confirmation in biparental populations and additional experiments.