Interaction and association analysis of malting related traits in barley.

Barley is considered as a foundation of the brewing and malting industry. Varieties with superior malt quality traits are required for efficient brewing and distillation processes. Among these, the Diastatic Power (DP), wort-Viscosity (VIS), ß-glucan content (BG), Malt Extract (ME) and Alpha-Amylase (AA) are controlled by several genes linked to numerous quantitative trait loci (QTL), identified for barley malting quality. One of the well-known QTL, QTL2, associated with barley malting trait present on chromosome 4H harbours a key gene, called as HvTLP8 that has been identified for influencing the barley malting quality through its interaction with ß-glucan in a redox-dependent manner. In this study, we examined to develop a functional molecular marker for HvTLP8 in the selection of superior malting cultivars. We first examined the expression of HvTLP8 and HvTLP17 containing carbohydrate binding domains in barley malt and feed varieties. The higher expression of HvTLP8 prompted us to further investigate its role as a marker for malting trait. By exploring the 1000 bp downstream 3' UTR region of HvTLP8, we found single nucleotide polymorphism (SNP) in between Steptoe (feed variety) and Morex (malt variety), which was further validated by Cleaved Amplified Polymorphic Sequence (CAPS) marker assay. Analysis of 91 individuals from the Steptoe x Morex doubled haploid (DH) mapping population revealed CAPS polymorphism in HvTLP8. Highly significant (p<0.001) correlations among ME, AA and DP malting traits were observed. The correlation coefficient (r) between these traits ranged from 0.53 to 0.65. However, the polymorphism in HvTLP8 did not correlate effectively with ME, AA, and DP. Altogether, these findings will help us to further design the experiment regarding the HvTLP8 variation and its association with other desirable traits.

Thaumatin-Like Protein (TLP) Gene Family in Barley: Genome-Wide Exploration and Expression Analysis during Germination.

Thaumatin-like Proteins (TLPs) are known to play a vital role in plant defense, developmental processes and seed germination. We identified 19 TLP genes from the reference genome of barley and 37, 28 and 35 TLP genes from rice, Brachypodium and sorghum genomes, respectively. Comparative phylogenetic analysis classified the TLP family into nine groups. Localized gene duplications with diverse exon/intron structures contributed to the expansion of the TLP gene family in cereals. Most of the barley TLPs were localized on chromosome 5H. The spatiotemporal expression pattern of HvTLP genes indicated their predominant expression in the embryo, developing grains, root and shoot tissues. Differential expression of HvTLP14, HvTLP17 and HvTLP18 in the malting variety (Morex) over 16-96 h of grain germination revealed their possible role in malting. This study provides a description of the TLP gene family in barley and their possible involvement in seed germination and the malting process.