Genome-Wide Identification and Transcriptional Expression Profiles of PP2C in the Barley (Hordeum vulgare L.) Pan-Genome.

The gene family protein phosphatase 2C (PP2C) is related to developmental processes and stress responses in plants. Barley (Hordeum vulgare L.) is a popular cereal crop that is primarily utilized for human consumption and nutrition. However, there is little knowledge regarding the PP2C gene family in barley. In this study, a total of 1635 PP2C genes were identified in 20 barley pan-genome accessions. Then, chromosome localization, physical and chemical feature predictions and subcellular localization were systematically analyzed. One wild barley accession (B1K-04-12) and one cultivated barley (Morex) were chosen as representatives to further analyze and compare the differences in HvPP2Cs between wild and cultivated barley. Phylogenetic analysis showed that these HvPP2Cs were divided into 12 subgroups. Additionally, gene structure, conserved domain and motif, gene duplication event detection, interaction networks and gene expression profiles were analyzed in accessions Morex and B1K-04-12. In addition, qRT-PCR experiments in Morex indicated that seven HvMorexPP2C genes were involved in the response to aluminum and low pH stresses. Finally, a series of positively selected homologous genes were identified between wild accession B1K-04-12 and another 14 cultivated materials, indicating that these genes are important during barley domestication. This work provides a global overview of the putative physiological and biological functions of PP2C genes in barley. We provide a broad framework for understanding the domestication- and evolutionary-induced changes in PP2C genes between wild and cultivated barley.

Genome-wide identification of PYL gene family in wheat: Evolution, expression and 3D structure analysis.

Here, 38 wheat PYL genes (TaPYLs) belonging to 13 homoeologous groups were identified using the genome-search method, with 26 and 12 PYL genes identified in Triticum dicoccoides and Aegilops tauschii, respectively. Phylogenetic relationship, conserved domain and molecular evolution analysis revealed that PYL genes showed highly conservative between wheat and theprogenitors. Interaction network and miRNA target prediction found that TaPYLs could interact with the important components of ABA signaling pathway and Tae-miR966b-3p might be a hub regulator mediating wheat ABA signal network. Furthermore, the tissue-specific and stress-responsive TaPYLs were detected through RNA-seq analysis. Expressions of 10 TaPYLs were validated by QPCR analysis and the homoeologous genes showed significantly differential expression, suggesting subfunctionalization of them has occurred. Finally, 3D structures of the TaPYL proteins were predicted by homology modeling. This study lays the foundation for further functional study of PYL genes for development and stress tolerance improvement in wheat and beyond.

Genomic and Phenotypic Divergence in Wild Barley Driven by Microgeographic Adaptation.

Microgeographic adaptation is a fundamental driving force of evolution, but the underlying causes remain undetermined. Here, the phenotypic, genomic and transcriptomic variations of two wild barley populations collected from sharply divergent and adjacent micro-geographic sites to identify candidate genes associated with edaphic local adaptation are investigated. Common garden and reciprocal transplant studies show that large phenotypic differentiation and local adaptation to soils occur between these populations. Genetic, phylogenetic and admixture analyses based on population resequencing show that significant genetic divergences occur between basalt and chalk populations. These divergences are consistent with the phenotypic variations observed in the field. Genome sweep analyses reveal 162.7 Mb of selected regions driven by edaphic local adaptation, in which 445 genes identified, including genes associated with root architecture, metal transport/detoxification, and ABA signaling. When the phenotypic, genomic and transcriptomic data are combined, HvMOR, encoding an LBD transcription factor, is determined to be the vital candidate for regulating the root architecture to adapt to edaphic conditions at the microgeographic scale. This study provides new insights into the genetic basis of edaphic adaptation and demonstrates that edaphic factors may contribute to the evolution and speciation of barley.