Growth, grain production, and physiological traits were evaluated for Hordeum marinum, Triticum aestivum (cv. Chinese Spring), and a H. marinum-T. aestivum amphiploid, when exposed to NaCl treatments in a nutrient solution. H. marinum was more salt tolerant than T. aestivum and the amphiploid was intermediate, both for vegetative growth and relative grain production. H. marinum was best able to 'exclude' Na + and Cl 2 , particularly at high external NaCl. At 300 mM NaCl, concentrations of Na + (153 mmol g 21 dry mass) and Cl 2(75 mmol g 21 dry mass) in the youngest fully-expanded leaf blade of H. marinum were, respectively, only 7% and 4% of those in T. aestivum; and in the amphiplolid the Na + and Cl 2 concentrations were 39% and 36% of those in T. aestivum. Glycinebetaine and proline concentrations in the youngest fully-expanded leaf blade of plants exposed to 200 mM NaCl were highest in H. marinum (128 and 60 mmol g 21 dry mass, respectively), lowest in T. aestivum (85 and 37 mmol g 21 dry mass), and intermediate in the amphiploid (108 and 54 mmol g 21 dry mass). Thus, salt tolerance of H. marinum was expressed in the H. marinum-T. aestivum amphiploid.

The various crop species are major agricultural products and play an indispensable role in sustaining human life. Over a long period, breeders strove to increase crop yield and improve quality through traditional breeding strategies. Today, many breeders have achieved remarkable results using modern molecular technologies. Recently, a new gene-editing system, named the clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 technology, has also succeeded in improving crop quality. It has become the most popular tool for crop improvement due to its versatility. It has accelerated crop breeding progress by virtue of its precision in specific gene editing. This review summarizes the current application of CRISPR/Cas9 technology in crop quality improvement. It includes the modulation in appearance, palatability, nutritional components and other preferred traits of various crops. In addition, the challenge in its future application is also discussed.

In wheat (Triticum aestivum) grain yield and grain protein content are negatively correlated, making the simultaneous increase of the two traits challenging. Apart from genetic approaches, modification of nitrogen fertilization offers a feasible option to achieve this aim. In this study, a range of traits related to nitrogen-use efficiency in six Australian bread wheat varieties were investigated under different nitrogen treatments using 3-year multisite field trials. Changes in the individual storage protein composition were detected by high-performance liquid chromatography. Our results indicated that wheat grain yield and grain protein content reacted similarly to nitrogen availability, with grain yield being slightly more sensitive than grain protein content, and that genotype is a vital determinant of grain protein yield. Measurement of the glutamine synthetase activity of flag leaves and developing grains revealed that high nitrogen availability prompted the participation of glutamine in biological processes. In addition, a more significant accumulation of gluten macropolymer was observed under the high-nitrogen treatment from 21 days post-anthesis, and the underlying mechanism was elucidated by a comparative proteomics study. A yeast two-hybrid experiment confirmed this mechanism. The results of this study revealed that peptidyl-prolyl cis-trans isomerase (PPIase) was SUMOylated with the assistance of small ubiquitin-related modifier 1 and that high nitrogen availability facilitated this connection for the subsequent protein polymerization. Additionally, luminal-binding protein 2 in the endoplasmic reticulum played a similar role to PPIase in the aggregation of protein under high-nitrogen conditions.

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SignificanceWheat grain avenin-like proteins (ALPs) have functions for dough quality and antifungal activities. A genome-wide characterization of ALP encoding genes in bread wheat is conducted. Results showed that most ALPs are transcriptionally active in developing grains and are up-regulated upon Bgt infection. The allelic diversity of ALPs in 21 natural populations of wild emmer wheat (WEW) in Israel were studied. Many ALP allelic variations in WEW were associated with regional environmental adaption. Our findings demonstrate that the diversifying natural selection through climatic and edaphic factors was a major driving force for the allelic diversity of ALP genes. The results indicate that WEW harbors a high genetic diversity of ALPs utilizable for wheat improvement.