Genetic changes in the genus Vitis and the domestication of vine

Identifying Candidate Genes for Grape (Vitis vinifera L.) Fruit Firmness through Genome-Wide Association Studies

The firmness of grape berries is a critical factor influencing their commercial feasibility and is highly valued by both breeders and consumers. However, grape berry firmness is a complex quantitative trait governed by multiple genes, and our understanding of its genetic regulatory network remains incomplete. To elucidate the genetic mechanisms underlying grape berry firmness, this study employed genome-wide association studies (GWAS) to identify potential candidate genes associated with fruit firmness and cellulose content and to explore the gene regulatory network that controls their variation. The comprehensive GWAS results identified CesA as a candidate gene potentially regulating fruit firmness through its involvement in cellulose biosynthesis. To validate these findings, whole-genome gene family identification analysis was conducted. Furthermore, the key gene VvCslD5 was selected for functional validation, which included overexpression studies and subcellular localization. This study provides valuable insights into the regulation of biosynthesis and transcriptional signaling pathways that govern the structure of grape cell walls as well as the mechanisms underlying variations in grape firmness. These findings establish a solid foundation for future functional analyses of grape traits and will enhance breeding practices aimed at improving grape quality.

The Transcriptional Landscape of Berry Skin in Red and White PIWI ("Pilzwiderstandsfähig") Grapevines Possessing QTLs for Partial Resistance to Downy and Powdery Mildews

PIWI, from the German word Pilzwiderstandsfähig, meaning "fungus-resistant", refers to grapevine cultivars bred for resistance to fungal pathogens such as Erysiphe necator (the causal agent of powdery mildew) and Plasmopara viticola (the causal agent of downy mildew), two major diseases in viticulture. These varieties are typically developed through traditional breeding, often crossbreeding European Vitis vinifera with American or Asian species that carry natural disease resistance. This study investigates the transcriptional profiles of exocarp tissues in mature berries from four PIWI grapevine varieties compared to their elite parental counterparts using RNA-seq analysis. We performed RNA-seq on four PIWI varieties (two red and two white) and their noble parents to identify differential gene expression patterns. Comprehensive analyses, including Differential Gene Expression (DEGs), Gene Set Enrichment Analysis (GSEA), Weighted Gene Co-expression Network Analysis (WGCNA), and tau analysis, revealed distinct gene clusters and individual genes characterizing the transcriptional landscape of PIWI varieties. Differentially expressed genes indicated significant changes in pathways related to organic acid metabolism and membrane transport, potentially contributing to enhanced resilience. WGCNA and k-means clustering highlighted co-expression modules linked to PIWI genotypes and their unique tolerance profiles. Tau analysis identified genes uniquely expressed in specific genotypes, with several already known for their defense roles. These findings offer insights into the molecular mechanisms underlying grapevine resistance and suggest promising avenues for breeding strategies to enhance disease resistance and overall grape quality in viticulture.

Exploring the patterns of evolution: Core thoughts and focus on the saltational model

The Modern Synthesis, a pillar in biological thought, united Darwin's species origin concepts with Mendel's laws of character heredity, providing a comprehensive understanding of evolution within species. Highlighting phenotypic variation and natural selection, it elucidated the environment's role as a selective force, shaping populations over time. This framework integrated additional mechanisms, including genetic drift, random mutations, and gene flow, predicting their cumulative effects on microevolution and the emergence of new species. Beyond the Modern Synthesis, the Extended Evolutionary Synthesis expands perspectives by recognizing the role of developmental plasticity, non-genetic inheritance, and epigenetics. We suggest that these aspects coexist in the plant evolutionary process; in this context, we focus on the saltational model, emphasizing how saltation events, such as dichotomous saltation, chromosomal mutations, epigenetic phenomena, and polyploidy, contribute to rapid evolutionary changes. The saltational model proposes that certain evolutionary changes, such as the rise of new species, may result suddenly from single macromutations rather than from gradual changes in DNA sequences and allele frequencies within a species over time. These events, observed in domesticated and wild higher plants, provide well-defined mechanistic bases, revealing their profound impact on plant diversity and rapid evolutionary events. Notably, next-generation sequencing exposes the likely crucial role of allopolyploidy and autopolyploidy (saltational events) in generating new plant species, each characterized by distinct chromosomal complements. In conclusion, through this review, we offer a thorough exploration of the ongoing dissertation on the saltational model, elucidating its implications for our understanding of plant evolutionary processes and paving the way for continued research in this intriguing field.