In order to better understand the molecular mechanisms associated with salinity tolerance, transcriptome analysis of a local salt-tolerant wheat landrace (i.e. Roshan) was performed under salt stress. Transcriptome sequencing yielded 137,508,542 clean reads using the Illumina HiSeq 2000 platform. The results of two alignment programs, i.e. STAR and HISAT2, were used separately to perform the analysis of differentially expressed genes (DEGs) using DESeq2. Finally, a total of 17,897 DEGs were identified by DESeq2. Moreover, gene ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses identified 108 GO terms and 62 significant KEGG pathways, of which ‘metabolic process’ and ‘metabolic pathways’ were the most abundant enriched term and pathway, respectively. Additionally, key salinity-tolerant genes, including asparagine synthetase, were also identified in the present study. Out of 87 identified families of transcription factors, GAI‐RGA ‐ and ‐SCR (GRAS) was one of the most important, which participates in signal transduction, and meristem maintenance and development. Eventually, to validate the gene expression levels, six DEGs were selected for a quantitative real-time polymerase chain reaction, and the results were in line with those of RNA-Seq. The findings of the current study can guide future genetic and molecular studies and allow a better understanding and improvement of salt tolerance in wheat.

Spotted spurge, a C4 species, is a summer annual weed, introduced to the Golestan province of Iran in 2006. A series of laboratory experiments were conducted at the Faculty of Agriculture, Ferdowsi University of Mashhad, Iran, to evaluate the influence of environmental factors on seed germination of spotted spurge. Seeds germinated over a constant temperature range of 25 to 45 C with a 14-h photoperiod and at 30 to 50 C in continuous darkness. Seeds germinated at alternating day/night temperature regimes of 25/15 to 45/35 C, with maximum germination (> 80%) at alternating day/night temperatures of 35/25, 40/30, and 45/35C. Germination increased from 23.5 to 98% as water potential increased from −0.6 to 0 MPa (control). Germination was > 85% at sodium chloride (NaCl) concentrations up to 80 mM, with no germination at 160 mM NaCl. Germination was not affected by pH, and it was > more than 95% at pH ranging from 4 to 9. The germination of seeds submerged in water for a period less than 3 wk was > 60%, whereas no germination was observed after 9 wk of submergence in water. The results of our study could help to develop effective management strategies for this species. The results also suggest that spotted spurge could invade most tropical regions of Iran.

Seedling emergence is the preliminary factor defining wheat adaptability and stability under salt stress. This study was led to assess the salinity tolerance amongst 226 synthetic hexaploid wheats (SHWs) evaluated against two check cultivars, the tolerant ‘S-24’ and the susceptible ‘PBW-343’ at three sodium chloride treatments (0, 100 and 200 mM). Highly significant and positive correlation was observed between germination % and germination index (r = 0.85), and between seedling height and weight (r = 0.85). All four traits across three treatments were transformed into the salt tolerance trait index and salt tolerance index (STI). STI had significant positive correlation with all four parameters indicating reliability of this index for ranking the tolerance levels. STI-based 20 best performing genotypes were known as being promising candidates for wheat breeding. Local tolerant check was amongst the top three tolerant accessions. Two SHWs, AUS30288 {Croc_1/Aegilops squarrosa (466)} and AUS34444 {Ceta/Ae. squarrosa (872)} outperformed S-24 with STI of 61.8 and 55.7, respectively. SHW with same durum parents were included in tolerant and susceptible categories indicating that tolerance is contributed by the Ae. squarrosa syn. tauschii parent of SHWs. In conclusion, this baseline study revealed that continuous variation in the seedling emergence traits under salt stress is a conduit towards implementing genome-wide association studies. Likewise, new diversity has implications in development of salt tolerance germplasm after genetic dissection permitting unique Ae. squarrosa accessional diversity validation to target SHW donors for breeding.

Germination and seedling growth of soybean (Glycine max L.) cv. Williams were examined on paper towels pre-moistened with a range of saline solutions (germination: 0–500 mMolal NaCl; seedling growth: 0–330 mMolal NaCl). The Na+, K+ and Ca2+ concentrations in the embryonic axis immediately before germination and in the seedling 3.5 d after germination were measured. Germination decreased at NaCl concentrations of 330 mMolal (81% germination) and above. At 420 mMolal NaCl, only 40% of seeds germinated, and at 500 mMolal NaCl there was no germination. Seedling growth rate decreased drastically with increasing salinity. At 220 mMolal NaCl, seedling growth rate had declined to 5% of the control, whereas at 330 mMolal NaCl seedling growth was almost zero 3–4 d after germination. Thus, soybean seeds were more tolerant of salinity in the germination than in the seedling phase. The results suggest that the greater tolerance of salinity during the germination phase might, in part, be the result of a lower sensitivity to high tissue Na+ concentrations. Germination (40%) was possible at a tissue Na+ concentration in the embryonic axis of 9.3 mg g FW-1, whereas seedling growth was completely inhibited at a tissue Na+ concentration of 6.1 mg g FW-1. Germination at higher tissue Na+ concentrations was associated with higher K+ and Ca2+ concentrations in the embryo axis, compared with growing seedlings, suggesting that these ions may protect the seeds in the pre-germination phase against salinity.