Horticulture Research

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Article|28 Feb 2024|OPEN

Chromosome-scale reference genome of broccoli (Brassica oleracea var. italica Plenck) provides insights into glucosinolate biosynthesis

Qiuyun Wu^1,2,3 ^,† , Shuxiang Mao^1,2,3 ^,† , Huiping Huang^1,2,3 , Juan Liu^1,2,3 , Xuan Chen^1,2,3 , Linghui Hou^1,2,3 , Yuxiao Tian^1,2,3 , Jiahui Zhang⁴ , Junwei Wang^1,2,3 ^, , Yunsheng Wang⁴ ^, , Ke Huang,^1,2,3 ^,

¹College of Horticulture, Hunan Agricultural University, Changsha, Hunan, 410128, China
²Engineering Research Center for Horticultural Crop Germplasm Creation and New Variety Breeding, Ministry of Education, Changsha, Hunan, 410128, China
³Key Laboratory for Vegetable Biology of Hunan Province, Changsha, Hunan, 410128, China
⁴Hunan Provincial Key Laboratory for Biology and Control of Plant Disease and Insect Pests, Hunan Agricultural University, Changsha, Hunan, 410128, China
*Corresponding author. E-mail: JunweiWang87@126.com,wyunsheng@gmail.com,huangke@hunau.edu.cn
^†Both authors contributed equally to the study.

Horticulture Research 11,
Article number: uhae063 (2024)
doi: https://doi.org/10.1093/hr/uhae063
Views: 1517

Received: 18 Aug 2023
Accepted: 19 Feb 2024
Published online: 28 Feb 2024

Abstract

Broccoli (Brassica oleracea var. italica Plenck) is an important vegetable crop, as it is rich in health-beneficial glucosinolates (GSLs). However, the genetic basis of the GSL diversity in Brassicaceae remains unclear. Here we report a chromosome-level genome assembly of broccoli generated using PacBio HiFi reads and Hi-C technology. The final genome assembly is 613.79 Mb in size, with a contig N50 of 14.70 Mb. The GSL profile and content analysis of different B. oleracea varieties, combined with a phylogenetic tree analysis, sequence alignment, and the construction of a 3D model of the methylthioalkylmalate synthase 1 (MAM1) protein, revealed that the gene copy number and amino acid sequence variation both contributed to the diversity of GSL biosynthesis in B. oleracea. The overexpression of BoMAM1 (BolI0108790) in broccoli resulted in high accumulation and a high ratio of C4-GSLs, demonstrating that BoMAM1 is the key enzyme in C4-GSL biosynthesis. These results provide valuable insights for future genetic studies and nutritive component applications of Brassica crops.