Multi-omic analysis reveals the effects of interspecific hybridization on the synthesis of seed reserve polymers in a Triticum turgidum ssp. durum × Aegilops sharonensis amphidiploid

Abstract

Abstract Background Wheat grain endosperm is mainly composed of proteins and starch. The contents and the overall composition of seed storage proteins (SSP) markedly affect the processing quality of wheat flour. Polyploidization results in duplicated chromosomes, and the genomes are often unstable and may result in a large number of genes loss and gene rearrangements. However ,the instability of the genome itself, as well as the large number of duplicated genes generated during polyploidy, is an important driving force for genetic innovation This study compared the differences of starch and SSP, and analyse the transcriptomeand and metabolome conducted among Ae. sharonensis, durum wheat and amphidiploid to reveal the effects of polyploidization on the synthesis of seed reserve polymers. Results The total starch and amylose content of Z636×R7 was significantly higher than R7 and lower than Z636. The gliadin and glutenin contents of Z636×R7 were higher than those in Z636 and R7. Through transcriptome analysis, there were 21037,2197,15090 differentially expressed genes in the three comparison groups of R7 vs Z636, Z636 vs Z636 × R7, Z636 × R7 vs R7, which were mainly enriched in carbon metabolism and amino acid biosynthesis pathways. Transcriptome data and qRT-PCR were combined to analyze the expression levels of genes related to storage substances. It was found that the expression levels of AGP-L, AGP-S and GBSSI of some starch synthase genes in Z636×R7 were higher than R7 and among the 17 differentially expressed genes related to storage proteins, the expression levels of 14 genes in R7 were lower than those in Z636 and Z636 × R7. According to the classification analysis of all differential metabolites, most of the metabolites belong to carboxylic acids and derivatives, fattyacyls, and are enriched in the biosynthesis of unsaturated fatty acids, niacin and nicotinamide metabolism, one carbon pool by flate etc. Conclusion After allopolyploidization, it may be affected by the exogenous genome, the organic synthesis function is down-regulated, the seed development cycle is prolonged, and the starch accumulation period is delayed. Therefore, at the same development time point, the starch accumulation of Z636 × R7 lags behind that of Z636. In this study, the expression of GSe2 gene in Z636 × R7 was higher than that of the two parents, which was beneficial to protein synthesis and thus increased protein content. These results eventually led to the alteration of synthesis of seed reserve polymers. The current study provided a basis for a greater in-depth understanding of the mechanism of wheat allopolyploid formation and its stable preservation and promote the effective exploitation of high-value alleles