The effects of salt stress on growth parameters, free proline content, ion accumulation, lipid peroxidation, and several antioxidative enzymes activities were investigated in S. persica and S. europaea. The seedlings were grown for 2 months in half-strength Hoagland solution and treated with different concentrations of NaCl (0, 85, 170, 340, and 510 mM) for 21 days. The fresh and dry weights of both species increased significantly at 85 and 170 mM NaCl and decreased at higher concentrations. Salinity increased proline content in both the species as compared to that of control. Sodium (Na ? ) content in roots and shoots increased, whereas K ? and P i content in both organs decreased. At all NaCl concentrations, the total amounts of Na ? and K ? were higher in shoots than in roots. Malondialdehyde (MDA) content declined at moderate NaCl concentrations (85 and 170 mM) and increased at higher levels. With increased salinity, superoxide dismutase (SOD), catalase (CAT), and guaiacol peroxidase (GPX) activities also increased gradually in both species. In addition, it seems that GPX, CAT, and SOD activities play an essential protective role in the scavenging reactive oxygen species (ROS) in both species. Native polyacrylamide gel electrophoresis (PAGE) indicated different isoform profiles between S. persica and S. europaea concerning antioxidant enzymes. These results showed that S. persica exhibits a better protection mechanism against oxidative damage and it is more salt-tolerant than S. europaea possibly by maintaining and/or increasing growth parameters, ion accumulation, and antioxidant enzyme activities.

Two of the important traits for wheat yield are tiller and fertile tiller number, both of which have been thought to increase cereal yield in favorable and unfavorable environments. A total of 6,349 single nucleotide polymorphism (SNP) markers from the 15 K wheat Infinium array were employed for genome-wide association study (GWAS) of tillering number traits, generating a physical distance of 14,041.6 Mb based on the IWGSC wheat genome sequence. GWAS analysis using Fixed and random model Circulating Probability Unification (FarmCPU) identified a total of 47 significant marker-trait associations (MTAs) for total tiller number (TTN) and fertile tiller number (FTN) in Iranian bread wheat under different water regimes. After applying a 5% false discovery rate (FDR) threshold, a total of 13 and 11 MTAs distributed on 10 chromosomes were found to be significantly associated with TTN and FTN, respectively. Linked single nucleotide polymorphisms for IWB39005 (2A) and IWB44377 (7A) were highly significantly associated (FDR < 0.01) with TTN and FTN traits. Moreover, to validate GWAS results, meta-analysis was performed and 30 meta-QTL regions were identified on 11 chromosomes. The integration of GWAS and meta-QTLs revealed that tillering trait in wheat is a complex trait which is conditioned by the combined effects of minor changes in multiple genes. The information provided by this study can enrich the currently available candidate genes and genetic resources pools, offering evidence for subsequent analysis of genetic adaptation of wheat to different climatic conditions of Iran and other countries. Bread wheat (Triticum aestivum L., genomes AABBDD, 2n = 6x = 42), is a major cereal crop, supplying 20% of the total energy and protein of the world's diet 1. Its production and productivity, especially in arid and semiarid regions such as Iran, are considerably constrained by extreme drought and heat stresses. Breeding for grain yield is the final step to produce stress-tolerant crop plants, since grain yield is a complex trait with low heritability, which is controlled by multiple genes and is affected by a lot of environmental factors, other traits such as yield components can be employed to overcome the limitations. Tillering is a crucial factor for wheat yield because of its involvement in grain weight and grain number determination. Moreover, it is a determinant of grain yield,

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Different rooting ability candidate genes were tested on an olive cross progeny. Our results demonstrated that only the AOX2 gene was strongly induced. OeAOX2 was fully characterised and correlated to phenotypical traits. The formation of adventitious roots is a key step in the vegetative propagation of trees crop species, and this ability is under strict genetic control. While numerous studies have been carried out to identify genes controlling adventitious root formation, only a few loci have been characterised. In this work, candidate genes that were putatively involved in rooting ability were identified in olive (Olea europaea L.) by similarity with orthologs identified in other plant species. The mRNA levels of these genes were analysed by real-time PCR during root induction in high- (HR) and low-rooting (LR) individuals. Interestingly, alternative oxidase 2 (AOX2), which was previously reported to be a functional marker for rooting in olive cuttings, showed a strong induction in HR individuals. From the OeAOX2 full-length gene, alleles and effective polymorphisms were distinguished and analysed in the cross progeny, which were segregated based on rooting. The results revealed a possible correlation between two single nucleotide polymorphisms of OeAOX2 gene and rooting ability.

Root architecture is an important bread wheat phenomenon that highly influences its production and adaptation to environmental stresses, in particular drought stress. Several QTL studies have been conducted to ascertain chromosomal regions associated with root morphology resulting in identification of various loci depending on evaluated population types and experimental conditions. In order to identify the most consistent and reliable QTLs involved in various root morphological traits in bread wheat, a meta-QTL (MQTL) analysis was performed using 106 QTLs derived from 12 different populations under both normal and drought stress conditions. Among them, 125 QTLs related to root traits were successfully projected onto the reference map and further metaanalysis was focused on chromosomes of homeologous groups 2 and 3 with most assigned QTLs. Consequently, a total of seven MQTLs were identified on chromosomes 2A, 2B, 3A and 3B originated from 2 to 17 initial QTLs with a confidence interval (CI) of 5.3-6.6 to 39.5-55.0 cM. Three MQTLs located on 2A, 3A and 3B derived from 7 to 17 QTLs related to different root morphological traits pointed out the most important chromosomal regions. A reduction in the average 95% confidence interval from 20.8 cM to 6.4 cM was observed when comparing the individual QTL to the MQTL. Further analysis on investigation of candidate genes located in these genomic regions resulted in identification of some genes mainly associated with lignin catabolic process, potassium transporters and leucine-rich repeats receptor-like kinases (LRR-RLKs). These results provid fundamental information on most important genomic regions and candidate genes related to root morphology in bread wheat.

In this study, high-throughput sequencing (RNA-Seq) was utilized to evaluate differential expression of transcripts and their related genes involved in response to terminal drought in root tissues of bread wheat landrace (L-82) and drought-sensitive genotype (Marvdasht). Subsets of 460 differentially expressed genes (DEGs) in drought-tolerant genotype and 236 in drought-sensitive genotype were distinguished and functionally annotated with 105 gene ontology (GO) terms and 77 metabolic pathways. Transcriptome profiling of drought-resistant genotype “L-82” showed up-regulation of genes mostly involved in Oxidation-reduction process, secondary metabolite biosynthesis, abiotic stress response, transferase activity and heat shock proteins. On the other hand, down-regulated genes mostly involved in signaling, oxidation-reduction process, secondary metabolite biosynthesis, auxin-responsive protein and lipid metabolism. We hypothesized that the drought tolerance in “L-82” was a result of avoidance strategies. Up-regulation of genes related to the deeper root system and adequate hydraulic characteristics to allow water uptake under water scarcity confirms our hypothesis. The transcriptomic sequences generated in this study provide information about mechanisms of acclimation to drought in the selected bread wheat landrace, “L-82”, and will help us to unravel the mechanisms underlying the ability of crops to reproduce and keep its productivity even under drought stress.

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