Polyploidization and genomic selection integration for grapevine breeding: a perspective

A Dataset of SNPs Related to Downy Mildew Resistance in East Asian Grape Based on GBTS

Grapevine is an important commercial crop widely grown in the world. However, grapevine cultivation has long been seriously threatened by grapevine downy mildew caused by Plasmopara viticola. Screening the resistance resources and identifying the resistance germplasm is the key to improve the resistance of cultivars to P. viticola. East Asia is one of the three origin regions of wild grapevine (North America, Eurasia and East Asia), and many varieties have strong disease resistance. In present study, we selected nine wild East Asian grape vines and selected three of them with the highest P. viticola resistance to construct genetic populations. Genotyping by Targeted Sequencing (GBTS) is a high-throughput and cost-effective technology for sequencing specific genome regions, and its application in genetic population analysis and disease resistance related markers identification has revealed that may be abundant P. viticola-resistant germplasm in East Asian grapes. Our sequencing data and disease resistance grade data provided a valuable reference for mining downy mildew resistant germplasm of East Asian grape and breeding resistant varieties.

Sensing, Adapting and Thriving: How Fruit Crops Combat Abiotic Stresses

Production of high-yield and high-quality fruits is always the long-term objective of fruit crop cultivation, which, however, is challenged by various abiotic stresses such as drought, extreme temperatures and high salinity, and the adverse impacts of abiotic stresses on fruit crops are exacerbated by climate change in recent years. To cope with these environmental stressors, fruit crops have evolved adaptative strategies involving physiological changes and molecular regulation. In this review, we summarise the relevent changes in photosynthesis, osmotic and reactive oxygen species (ROS) equilibrium, metabolism and protein homeostasis in response to abiotic stresses. Moreover, perception of environmental stimuli as well as recent progress of underlying regulatory mechanisms is also discussed. Based on our current knowledge, possible strategies for stress resilience improvement in fruit crops are accordingly proposed. In addition, we also discuss the challenges in identification of key nodes in plant responses to multiple stresses and development of stress-resilient fruit crops, and addressing these issues in the future would advance our understanding of how fruit crops combat abiotic stresses and facilitate the breeding of superior fruit crops that can adapt to and thrive in the changing environments.

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.

Comparative assessment of morphological, cytological, and photosynthetic characteristics of the induced octoploid and its tetraploid counterpart of Celosia argentea L

BACKGROUND

Celosia argentea is a widely recognized plant for its ornamental qualities and therapeutic uses in traditional medicine. As demand for such multipurpose plants grows, enhancing its phenotypic and physiological traits could further expand its commercial potential. Polyploidization, particularly through chemical treatments like oryzalin, offers a method to induce genetic variation and potentially improve desirable traits in plants.

RESULTS

Tetraploid (2n = 4×= 36) nodal segments of C. argentea were treated with oryzalin under in vitro conditions, resulting in successful induction of octoploidy (2n = 8×= 72). Flow cytometry and chromosome counting confirmed polyploidization, with the highest induction rate achieved using 40 µM oryzalin for 24 h. Comparative analyses between octoploid and tetraploid plants revealed significant differences in morphological traits, including increased stem and leaf thickness, larger leaf area, inflorescence characteristics and more compact growth in the octoploids. Additionally, octoploids exhibited enhanced chlorophyll content and altered photosynthetic characteristics, along with notable changes in stomatal size and density. Ploidy stability was maintained across generations, ensuring the heritability of the induced traits.

CONCLUSIONS

In vitro polyploidization in C. argentea led to significant phenotypic and physiological improvements, demonstrating its potential for application in ornamental horticulture and plant breeding. This research contributes to the understanding of the impact of in vitro polyploidization on plant development, offering insights for the commercial cultivation and enhancement of C. argentea.

CLINICAL TRIAL NUMBER

Not applicable.

Synthetic polyploid induction influences morphological, physiological, and photosynthetic characteristics in Melissa officinalis L

Melissa officinalis L., a well-known herb with diverse industrial and ethnopharmacological properties. Although, there has been a significant lack in the breeding attempts of this invaluable herb. This study aimed to enhance the agronomical traits of M. officinalis through in vitro polyploidization. Nodal segments were micropropagated and subjected to oryzalin treatment at concentrations of 20, 40, and 60 mM for 24 and 48 hours. Flow cytometry, chromosome counting, and stomatal characteristics were employed to confirm the ploidy level of the surviving plants. The survival rate of the treated explants decreased exponentially with increasing oryzalin concentration and duration. The highest polyploid induction rate (8%) was achieved with 40 mM oryzalin treatment for 24 hours. The induced tetraploid plants exhibited vigorous growth, characterized by longer shoots, larger leaves, and a higher leaf count. Chlorophyll content and fluorescence parameters elucidated disparities in photosynthetic performance between diploid and tetraploid genotypes. Tetraploid plants demonstrated a 75% increase in average essential oil yield, attributed to the significantly larger size of peltate trichomes. Analysis of essential oil composition in diploid and tetraploid plants indicated the presence of three major components: geranial, neral, and citronellal. While citronellal remained consistent, geranial and neral increased by 11.06% and 9.49%, respectively, in the tetraploid population. This effective methodology, utilizing oryzalin as an anti-mitotic agent for polyploid induction in M. officinalis, resulted in a polyploid genotype with superior morpho-physiological traits. The polyploid lemon balm generated through this method has the potential to meet commercial demands and contribute significantly to the improvement of lemon balm cultivation.