Integrative Genomic Approaches Reveal Mechanisms of Garlic Storability

Garlic (Allium sativum L.) is one of the world's most widely consumed spices and health supplements, with China producing 80% of the international supply. However, its long growth cycle and the need for year-round availability demand effective storage. Bulbs often suffer sprouting, water loss, and rot, lowering market value and nutritional quality. Storage losses may reach 40% under conventional conditions, and current solutions rely heavily on cold storage, packaging, and chemical control, all of which increase costs. While sprouting, hormonal imbalance, and pathogen attacks are recognized contributors, the precise molecular mechanisms remain unclear. Due to these challenges, it is necessary to conduct in-depth research on the genetic basis of garlic storability.

A research team from the Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, published (DOI: 10.1093/hr/uhae260) their study on September 16, 2024, in Horticulture Research. The researchers systematically evaluated the bulb storability of 501 garlic accessions worldwide and combined genome-wide association, selective sweep, and transcriptomic analyses. Their integrated approach identified 21 key candidate genes and several regulatory pathways that determine whether garlic bulbs resist sprouting and decay, offering genetic targets for improving postharvest quality and reducing losses.

The study first assessed four storability traits-decay index, decay rate, sprouting rate, and bud-to-clove ratio-across 501 garlic accessions from 38 countries. Forty-three accessions demonstrated strong storability, while 33 showed rapid decay. Morphological and cytological comparisons revealed that storability was linked to slower nutrient transfer through vascular bundles and delayed sprout growth. Genome-wide association studies uncovered 234 SNPs associated with storability, linked to 401 genes involved in stress defense, hormone signaling, and transport functions. Selective sweep analysis further highlighted 44 genes under selection in long-storing accessions. Transcriptome sequencing compared two contrasting varieties during storage, identifying nearly 16,000 differentially expressed genes. Key pathways included abscisic acid–mediated dormancy regulation and defense responses. A co-expression network highlighted three hub genes-Asa6G00043, Asa2G02374 (alliinase), and Asa7G05726 (cytochrome P450)-as central regulators. Ultimately, 21 candidate genes were identified as critical for storability, many linked to antioxidant defense, hormone balance, and metabolite transport. These findings provide valuable molecular resources to accelerate garlic breeding for postharvest resilience.

Garlic losses during storage are a major barrier to improving farmer income and market stability. By integrating genomic and transcriptomic analyses, we uncovered key genes that control sprouting, decay resistance, and dormancy maintenance. These discoveries not only explain the biological basis of storability but also supply powerful genetic tools for breeders. Our research paves the way for developing garlic varieties that maintain quality during long storage periods, reducing waste and improving availability for consumers worldwide."

Dr. Haiping Wang, corresponding author of the study

The identification of storability-related genes opens new avenues for molecular breeding of garlic with improved shelf life. Breeders can now target candidate genes associated with antioxidant production, hormone regulation, and nutrient transport to create varieties less prone to sprouting and decay. Such advances could reduce the reliance on costly cold storage and chemical treatments, lowering production expenses and food waste. Moreover, enhancing storability supports global trade by extending export windows and ensuring stable supply. Ultimately, these findings benefit producers, traders, and consumers alike by improving the sustainability, profitability, and year-round availability of one of the world's most important spices.