Small RNAs and their targets are associated with the transgenerational effects of water-deficit stress in durum wheat

Water-deficit stress negatively affects wheat yield and quality. Abiotic stress on the parental plants during reproduction could have transgenerational effects on the progenies. Here we investigated the transgenerational influence of pre-anthesis water-deficit stress by detailed analysis of the yield components, grain quality traits, and physiological traits in durum wheat. Next-generation sequencing analysis profiled the small RNA-omics, mRNA transcriptomics, and mRNA degradomics in the progenies. Parental water-deficit stress had positive impacts on the progenies in certain traits like harvest index and protein content in given genotype. Small RNA-seq identified 1739 conserved and 774 novel microRNAs (miRNAs). Transcriptome-seq characterised the expression of 66,559 genes while degradome-seq profiled the miRNA-guided mRNA cleavage dynamics. Differentially expressed miRNAs and genes were identified, with significant regulatory patterns subject to trans- and inter- generational stress. Integrated analysis based on the three omics revealed the significant biological interactions between stress-responsive miRNA and targets, with possible contributions towards transgenerational stress tolerance via pathways such as hormone signalling and nutrient metabolism. Our study provides the first confirmation of the transgenerational effects of water-deficit stress in durum wheat. New insights gained on the molecular level indicate that key miRNA-mRNA modules are potential candidates in transgenerational stress improvement. Overall design: Analysis of small RNA transcriptome, mRNA transcriptome and mRNA degradome in eight biological pools (four treatment groups by two tissue types)