Sulphur-nitrogen fertilization strategy and mechanism underlying wheat grain protein composition and quality
1. Australia-China Joint Centre for Wheat Improvement,School of veterinary and life sciences,Murdoch University2. Department of Agriculture and Food Western Australia
摘要：Wheat（Triticum aestivum L.） is receiving increasing attention on its quality improvement.To achieve high wheat quality,sulphur fertilizer application is essential,whilst adequate amount of nitrogen fertilizer can trigger the positive effects of sulphur.Important agronomic traits and protein parameters such as NUE（nitrogen use efficiency）,harvest index,protein percentage,and protein yield are targeted.HPLC analysis results demonstrated that with the increasing ratio of sulphur fertilizer,the percentage of UPP and the ratio of glutenins to gliadins are both increased.For protein compositions,the HMW-GS to LMW-GS ratio is reduced,the percentage of α/β-gliadins is decreased,whereas the percentage ofγ-gliadins is increased.Based on above results,two comparative treatments（S0N50 and S30N50） in three grain-filling stages（7DPA,14 DPA and21DPA） are selected for RNA-seq experimental design in order to screen differential expressed genes（DEGs）.The survey sequence from IWGCS is used as reference for alignment and mapping in bioinformatics analysis.The preliminary results revealed that there are 3 up-regulated genes and62 down-regulated genes between low and high sulphur treatments,whilst there are 14,983 up-regulated genes and 11,621 down-regulated genes among the grain-filling stages.Gene ontology（GO） enrichment analysis illustrated that roughly 230 DEGs involve in biological process,whereas nearly 75 DEGs take participate in molecular function.Among them,there are 4 DEGs enriched in glutamine biosynthetic process,organic acid biosynthetic process,carboxylic acid biosynthetic process and singleorganism metabolic process.Afterwards,the KEGG pathway enrichment analysis identified the interactions of above DEGs are significantly enriched in alanine,aspartate and glutamate metabolism,glyoxylate and dicarboxylate metabolism,nitrogen metabolism,and arginine and proline metabolism.At last,through blastx the translated target gene sequence to Bdi（Brachypodium distachyon） protein sequence in STRING database,the predicted protein-protein interactions network（PPI） is constructed.