Unlocking garlic’s secret to long-term freshness

Garlic, a globally significant food and medicinal crop, suffers major quality loss during storage due to sprouting and decay. In a comprehensive study, researchers evaluated the bulb storability of 501 garlic accessions from 38 countries. Through integrated genome-wide association studies (GWAS), transcriptome sequencing, and cytological observations, the team identified key phenotypic traits, genetic loci, and candidate genes associated with superior storage performance. Notably, 21 candidate genes linked to dormancy regulation, stress response, and nutrient transport were highlighted. This research provides foundational knowledge for molecular breeding of garlic varieties with extended shelf life, aiming to reduce postharvest losses and boost garlic's economic value worldwide.

Garlic (Allium sativum L.) is not only a culinary staple but also a potent source of bioactive compounds. However, it faces severe postharvest quality degradation, especially under prolonged storage, resulting in sprouting, decay, and loss of nutritional value. Traditional storage methods rely on costly environmental controls, and conventional breeding for storability has proven inefficient due to garlic's asexual propagation. While prior studies focused on specific biochemical or microbial aspects, a comprehensive understanding of the genetic regulation behind bulb storability remained limited. Due to these challenges, it is crucial to systematically explore the genetic architecture and molecular mechanisms controlling garlic storability through large-scale and integrative approaches.

A research team from the Chinese Academy of Agricultural Sciences has unveiled critical genetic insights into garlic bulb storability, according to a study (DOI: 10.1093/hr/uhae260) published on September 16, 2024, in Horticulture Research. By evaluating 501 garlic accessions over two years, the scientists identified phenotypic markers and genetic variants that contribute to improved storage life. Using integrated genome-wide association studies (GWAS) and transcriptomic analyses, the team pinpointed key genes related to dormancy, stress resistance, and substance transport, laying the groundwork for breeding garlic varieties with enhanced postharvest performance.

The study evaluated storability traits—including decay index (DI), decay rate, sprouting rate, and bud-to-clove ratio—in garlic bulbs from 38 countries. DI emerged as a reliable indicator, showing high heritability and strong correlation with other traits. Morphological and cytological comparisons between high-storability (e.g., accession 8N035) and low-storability (e.g., 8N258) garlic revealed slower nutrient transfer and bud growth in durable accessions.

Through GWAS, researchers identified 234 SNPs linked to storability traits, corresponding to 401 genes involved in resistance, metabolism, and hormone response. Selective sweep analysis further narrowed down 44 genes under natural selection in strong-storage garlic. Transcriptome profiling across four storage timepoints uncovered 15,956 differentially expressed genes, with patterns suggesting early stress response in durable accessions and hormone-related dormancy differences.

Co-expression network analysis highlighted three hub genes—Asa6G00043, Asa2G02374, and Asa7G05726—involved in GA signaling, allicin synthesis, and xenobiotic detoxification, respectively. The final integration of GWAS, sweep, and transcriptome data revealed 21 critical candidate genes that regulate storability through hormone signaling, defense, and transport pathways.

“Our findings offer the first comprehensive look at the genetic blueprint underlying garlic storability,” said Dr. Haiping Wang, corresponding author of the study. “By integrating genomic, transcriptomic, and physiological data, we've identified molecular targets that can guide future breeding programs. These candidate genes provide powerful tools for developing garlic varieties with longer shelf life, which could significantly reduce postharvest losses and improve garlic's commercial value across the globe.”

This study opens the door to molecular breeding of garlic with improved storability by providing genetic markers and candidate genes for targeted selection. The identified genes—particularly those involved in hormone regulation, antioxidant synthesis, and nutrient transport—may serve as key targets for gene editing and transgenic approaches. Enhancing garlic's resistance to decay and sprouting during storage could reduce economic losses, lower cold storage costs, and extend market availability. Future work will focus on validating these genes in functional studies and applying them in breeding pipelines to cultivate robust garlic varieties fit for modern supply chains.

###

References

DOI

10.1093/hr/uhae260

Original Source URL

https://doi.org/10.1093/hr/uhae260

Funding information

This work was financially supported by the Natural Science Foundation of China (32172566, 32272731, and 31872946), Youth Innovation Special Task of Chinese Academy of Agricultural Sciences (Y2023QC06), Key R&D Program of Shandong Province of China (2022LZGCQY015),Innovation Engineering Project of Chinese Academy of Agricultural Sciences (CAAS-ASTIP-2021-IVF), Safe Preservation Project Of Crop Germplasm Resources of MOF (2024NWB037), National Horticultural Germplasm Centre Project (NHGRC2024-NH01), and National Modern Agricultural Industry Technology System Construction Special Fund Project (CARS-24-A-01).

About Horticulture Research

Horticulture Research is an open access journal of Nanjing Agricultural University and ranked number one in the Horticulture category of the Journal Citation Reports ™ from Clarivate, 2023. The journal is committed to publishing original research articles, reviews, perspectives, comments, correspondence articles and letters to the editor related to all major horticultural plants and disciplines, including biotechnology, breeding, cellular and molecular biology, evolution, genetics, inter-species interactions, physiology, and the origination and domestication of crops.