Transcriptome and QTL mapping analyses of major QTL genes controlling glucosinolate contents in vegetable- and oilseed-type Brassica rapa plants

Jin A Kim; Heewon Moon; Hyang Suk Kim; Dasom Choi; Nan-Sun Kim; Juna Jang; Sang Woo Lee; Adji Baskoro Dwi Nugroho; Dong-Hwan Kim

doi:10.3389/fpls.2022.1067508

Transcriptome and QTL mapping analyses of major QTL genes controlling glucosinolate contents in vegetable- and oilseed-type Brassica rapa plants

Front Plant Sci. 2023 Jan 18:13:1067508. doi: 10.3389/fpls.2022.1067508. eCollection 2022.

Authors

Jin A Kim¹, Heewon Moon², Hyang Suk Kim¹, Dasom Choi², Nan-Sun Kim¹, Juna Jang¹, Sang Woo Lee², Adji Baskoro Dwi Nugroho², Dong-Hwan Kim²

Affiliations

¹ Department of Agricultural Biotechnology, National Institute of Agricultural Science, Rural Development Administration, Jeonju, Jeollabuk-do, Republic of Korea.
² Department of Plant Science and Technology, Chung-Ang University, Anseong, Republic of Korea.

Abstract

Glucosinolates (GSLs) are secondary metabolites providing defense against pathogens and herbivores in plants, and anti-carcinogenic activity against human cancer cells. Profiles of GSLs vary greatly among members of genus Brassica. In this study, we found that a reference line of Chinese cabbage (B. rapa ssp. pekinensis), 'Chiifu' contains significantly lower amounts of total GSLs than the oilseed-type B. rapa (B. rapa ssp. trilocularis) line 'LP08'. This study aimed to identify the key regulators of the high accumulation of GSLs in Brassica rapa plants using transcriptomic and linkage mapping approaches. Comparative transcriptome analysis showed that, in total, 8,276 and 9,878 genes were differentially expressed between 'Chiifu' and 'LP08' under light and dark conditions, respectively. Among 162 B. rapa GSL pathway genes, 79 were related to GSL metabolism under light conditions. We also performed QTL analysis using a single nucleotide polymorphism-based linkage map constructed using 151 F₅ individuals derived from a cross between the 'Chiifu' and 'LP08' inbred lines. Two major QTL peaks were successfully identified on chromosome 3 using high-performance liquid chromatography to obtain GSL profiles from 97 F₅ recombinant inbred lines. The MYB-domain transcription factor gene BrMYB28.1 (Bra012961) was found in the highest QTL peak region. The second highest peak was located near the 2-oxoacid-dependent dioxygenase gene BrGSL-OH.1 (Bra022920). This study identified major genes responsible for differing profiles of GSLs between 'Chiifu' and 'LP08'. Thus, our study provides molecular insights into differences in GSL profiles between vegetative- and oilseed-type B. rapa plants.

Keywords: BrMYB28.1; Brassica rapa; QTL mapping; glucosinolate; transcriptome.

Grants and funding

This work was supported by the Chung-Ang University Graduate Research Scholarship, awarded to HM in 2022, as well as the “New breeding technologies development Program of the Rural Development Administration, Republic of Korea” (project No. PJ01654101; funding awarded to JK) and NRF (2021R1F1A1047822; funding awarded to D-HK).