Inheritance and Genetic Mapping of Late-Bolting to Early-Bolting Gene, BrEb-1, in Chinese Cabbage (Brassica rapa L.)

Abstract

Chinese cabbage (Brassica rapa L.) is one of the most important and highly nutritious vegetables in China belonging to the Brassicaceae family. Flowering or bolting is one of the most critical developmental stages in flowering plants. For the spring-sown Chinese cabbage, late-bolting is desirable over early-bolting according to consumer preferences. We determined the inheritance pattern of the late-bolting trait using F1 and F2 generated from a cross between ‘SY2004’ (late-bolting) and ‘CX14-1’ (early-bolting). The genetic analysis revealed that the late-bolting to early-bolting trait was controlled by an incomplete dominant gene that we named BrLb-1. Furthermore, we performed bulked segregant analysis (BSA) via whole genome re-sequencing and the results showed that this gene was harbored on the chromosome A07 at the intersections of 20,070,000 to 25,290,000 bp and 20,330,000 to 25,220,000, an interval distance of 4.89 Mb. In this candidate interval, totals of 2321 and 1526 SNPs with non-synonymous mutations, and 229 and 131 InDels with frameshift mutations, were found between the parents and the bulked pools, respectively. Furthermore, we identified three putative candidate genes for the late-bolting trait, including BraA07g029500, BraA07g029530 and BraA07g030360, which code for the AGAMOUS-like MADS-box protein AGL12, a pentatricopeptide repeat-containing protein and NAC transcription factor 29, respectively; however, further functional analysis is required. These genetic variants could be utilized for the further development of molecular markers for marker-assisted breeding in Chinese cabbage.

Introducing gene-edited copies of BrSOC1 genes into late-bolting inbred Chinese cabbage lines effectively delays bolting

“…In a recent investigation, F1 hybrids with intermediate bolting characteristics were identi ed through crossing early-bolting and late-bolting lines [29]. In our study, F1 hybrids derived from the cross 20 × brsoc1-1 brsoc1-2 brsoc1-3 also exhibited a moderately late bolting trait compared with the maternal line 20, aligning with the ndings of Wei et al (2022) (Fig.…”

Advancements in Molecular Mechanism Research on Bolting Traits in Vegetable Crops

“…Bolting traits in crops are influenced by major genes and polygenes, with significant environmental variance. Genetic analyses reveal additive-dominant-epistatic effects in crops like Chinese cabbage and cabbage, aiding in the selection of bolting tolerance in early generations [105,[126][127][128]. Two major genes expressed in the mode of additive-dominant-epistatic (D-2) effects mainly controlled the bolting trait, and the additive effects of the two major genes were similar in Chinese cabbage [105,[126][127][128], cabbage [51,129], pakchoi [130], and carrot [16,20].…”

“…Genetic analyses reveal additive-dominant-epistatic effects in crops like Chinese cabbage and cabbage, aiding in the selection of bolting tolerance in early generations [105,[126][127][128]. Two major genes expressed in the mode of additive-dominant-epistatic (D-2) effects mainly controlled the bolting trait, and the additive effects of the two major genes were similar in Chinese cabbage [105,[126][127][128], cabbage [51,129], pakchoi [130], and carrot [16,20]. However, the environmental variance was high in total variance, so selecting for bolting tolerance was in its early stages [130].…”