Transcriptome and Proteome Co-Profiling Offers an Understanding of Pre-Harvest Sprouting (PHS) Molecular Mechanisms in Wheat (Triticum aestivum)

Mapping of a Major-Effect Quantitative Trait Locus for Seed Dormancy in Wheat

The excavation and utilization of dormancy loci in breeding are effective endeavors for enhancing the resistance to pre-harvest sprouting (PHS) of wheat varieties. CH1539 is a wheat breeding line with high-level seed dormancy. To clarify the dormant loci carried by CH1539 and obtain linked molecular markers, in this study, a recombinant inbred line (RIL) population derived from the cross of weak dormant SY95-71 and strong dormant CH1539 was genotyped using the Wheat17K single-nucleotide polymorphism (SNP) array, and a high-density genetic map covering 21 chromosomes and consisting of 2437 SNP markers was constructed. Then, the germination percentage (GP) and germination index (GI) of the seeds from each RIL were estimated. Two QTLs for GP on chromosomes 5A and 6B, and four QTLs for GI on chromosomes 5A, 6B, 6D and 7A were identified. Among them, the QTL on chromosomes 6B controlling both GP and GI, temporarily named QGp/Gi.sxau-6B, is a major QTL for seed dormancy with the maximum phenotypic variance explained of 17.66~34.11%. One PCR-based diagnostic marker Ger6B-3 for QGp/Gi.sxau-6B was developed, and the genetic effect of QGp/Gi.sxau-6B on the RIL population and a set of wheat germplasm comprising 97 accessions was successfully confirmed. QGp/Gi.sxau-6B located in the 28.7~30.9 Mbp physical position is different from all the known dormancy loci on chromosomes 6B, and within the interval, there are 30 high-confidence annotated genes. Our results revealed a novel QTL QGp/Gi.sxau-6B whose CH1539 allele had a strong and broad effect on seed dormancy, which will be useful in further PHS-resistant wheat breeding.

Multi-omics combined with MALDI mass spectroscopy imaging reveals the mechanisms of biosynthesis of characteristic compounds in Tetrastigma hemsleyanum Diels et Gilg

Tetrastigma hemsleyanum Diels et Gilg is recognized as a source of extracts with various desirable bioactivities. However, current knowledge regarding the mechanisms of biosynthesis of flavonoids, phenolic compounds, and other bioactive chemicals is limited. We conducted comprehensive tissue distribution studies and biosynthetic analyses of the 26 main bioactive compounds of this plant. The majority of flavonoids exhibited higher concentrations in the cortex (CT) compared to the vascular cylinder (VC). The expression levels of genes and proteins in CT and VC were quantified using mRNA sequencing and isobaric tags for relative and absolute quantification (iTRAQ). A total of 31,700 genes were identified, among which 4921 exhibited differential expression between CT and VC. A total of 13,996 proteins were identified in the proteomes of CT and VC, with 927 showing differential expression. Co-expression network analyses of DEGs and DEPs from multiple sites demonstrated substantial pathway variations linked to flavonoid biosynthesis. Through differential enrichment analysis, a total of 32 genes involved in the flavone biosynthesis pathway were identified, with iTRAQ specifically detecting C3'H, F3H and FLS. Pearson correlation analysis revealed a strong association between the expression levels of C3'H, F3H, and FLS and the concentrations of flavonoids. The validation of multiple genes encoding pivotal enzymes was conducted using real-time fluorescence quantitative PCR (RT-qPCR). The findings provide a foundation for future investigations into the molecular mechanisms and functional characterization of T. hemsleyanum candidate genes associated with characteristic compounds.

Multi-Omics Uncover the Mechanism of Wheat under Heavy Metal Stress

Environmental pollution of heavy metals has received growing attention in recent years. Heavy metals such as cadmium, lead and mercury can cause physiological and morphological disturbances which adversely affect the growth and quality of crops. Wheat (Triticum aestivum L.) can accumulate high contents of heavy metals in its edible parts. Understanding wheat response to heavy metal stress and its management in decreasing heavy metal uptake and accumulation may help to improve its growth and grain quality. Very recently, emerging advances in heavy metal toxicity and phytoremediation methods to reduce heavy metal pollution have been made in wheat. Especially, the molecular mechanisms of wheat under heavy metal stress are increasingly being recognized. In this review, we focus on the recently described epigenomics, transcriptomics, proteomics, metabolomics, ionomics and multi-omics combination, as well as functional genes uncovering heavy metal stress in wheat. The findings in this review provide some insights into challenges and future recommendations for wheat under heavy metal stress.