Genetic dissection of morphological variation in rosette leaves and leafy heads in cabbage (Brassica oleracea var. capitata).

Abstract

Cabbage (B. oleracea var. capitata) is an economically important vegetable crop cultivated worldwide. Cabbage plants go through four vegetative stages: seedling, rosette, folding and heading. Rosette leaves are the largest leaves of cabbage plants and provide most of the energy needed to produce the leafy head. To understand the relationship and the genetic basis of leaf development and leafy head formation, 308 cabbage accessions were scored for rosette leaf and head traits in three-year field trials. Significant correlations were found between morphological traits of rosette leaves and heads, namely leaf area with the head area, height and width, and leaf width with the head area and head height, when heads were harvested at a fixed number of days after sowing. Fifty robust quantitative trait loci (QTLs) for rosette leaf and head traits distributed over all nine chromosomes were identified with genome-wide association studies (GWAS). All these 50 loci were identified in multiple years and generally affect multiple traits. Twenty-five of the QTL were associated with both rosette leaf and leafy head traits. We discuss sixteen candidate genes identified in these QTL with an annotation related to auxin and other phytohormones, leaf development, and leaf polarity that likely play a role in leafy head development or rosette leaf expansion.

Cabbage (Brassica oleracea var. capitata) Development in Time: How Differential Parenchyma Tissue Growth Affects Leafy Head Formation

“…This suggests that both cell division and expansion in cabbage leaves are co-regulated by the developmental stage. This finding is consistent with previous research, such as the study by Alemán-Báez et al [20], which reported that miR396b and its interacting GRF gene, both involved in cell division during leaf development, were differentially expressed between the young rosette and heading leaves in cabbage. Similarly, Mao et al [5] showed that the miR319-TCP4 interaction, also regulating cell division and expansion across the leaf blade, influences both rosette leaf growth and the head shape of Chinese cabbage [5].…”

“…Studies on cabbage and Chinese cabbage have shown that the genes responsible for establishing abaxial/adaxial leaf polarity [12,13,23,24], as well as those involved in cell division and expansion [5,7] during leaf development, are crucial for the formation of the leafy head. Additionally, microRNAs that regulate these leaf development genes also play a significant role in this process [5,20,23].…”

Exploration of the leafy head development in cabbage (Brassica oleracea)

“…This suggests that both cell division and expansion in cabbage leaves are co-regulated by the developmental stage. This finding is consistent with previous research, such as the study by Alemán-Báez et al (2024), which reported that miR396b and its interacting GRF gene, both involved in cell division during leaf development, were differentially expressed between the young rosette and heading leaves in cabbage.…”

“…Studies on cabbage and Chinese cabbage have shown that genes responsible for establishing abaxial/adaxial leaf polarity (Cheng et al, 2016;Liang et al, 2016;Ren et al, 2018;Li et al, 2024), as well as those involved in cell division and expansion (Mao et al, 2014;Alemán-Báez et al, 2022) during leaf development, are crucial for the formation of the leafy head. Additionally, microRNAs that regulate these leaf development genes also play a significant role in this process (Mao et al, 2014;Ren et al, 2018;Alemán-Báez et al, 2024).…”

“…To perform association analysis, the reference genome was partitioned into two types of regions: the "candidate regions" and "background regions". The candidate regions include the 50 QTL (Supplementary Table 3) identified by Alemán-Báez et al ( 2022) that we want to validate, as well as the 38 DEGs (Supplementary Table 4) identified by Alemán-Báez et al (2024). To define these candidate regions, we expanded the original border limits of each of the 50 QTL regions (Supplementary Table 3) by 55 Kb in both up-and downstream directions to include neighboring genomic regions that are in linkage disequilibrium with the QTL regions.…”