Dataset Information

Seed colour loci, homoeology and linkage groups of the C genome chromosomes revealed in Brassica rapa-B. oleracea monosomic alien addition lines.

ABSTRACT:

Background and aims

Brassica rapa and B. oleracea are the progenitors of oilseed rape B. napus. The addition of each chromosome of B. oleracea to the chromosome complement of B. rapa results in a series of monosomic alien addition lines (MAALs). Analysis of MAALs determines which B. oleracea chromosomes carry genes controlling specific phenotypic traits, such as seed colour. Yellow-seeded oilseed rape is a desirable breeding goal both for food and livestock feed end-uses that relate to oil, protein and fibre contents. The aims of this study included developing a missing MAAL to complement an available series, for studies on seed colour control, chromosome homoeology and assignment of linkage groups to B. oleracea chromosomes.

Methods

A new batch of B. rapa-B. oleracea aneuploids was produced to generate the missing MAAL. Seed colour and other plant morphological features relevant to differentiation of MAALs were recorded. For chromosome characterization, Snow's carmine, fluorescence in situ hybridization (FISH) and genomic in situ hybridization (GISH) were used.

Key results

The final MAAL was developed. Morphological traits that differentiated the MAALs comprised cotyledon number, leaf morphology, flower colour and seed colour. Seed colour was controlled by major genes on two B. oleracea chromosomes and minor genes on five other chromosomes of this species. Homoeologous pairing was largely between chromosomes with similar centromeric positions. FISH, GISH and a parallel microsatellite marker analysis defined the chromosomes in terms of their linkage groups. Conclusions A complete set of MAALs is now available for genetic, genomic, evolutionary and breeding perspectives. Defining chromosomes that carry specific genes, physical localization of DNA markers and access to established genetic linkage maps contribute to the integration of these approaches, manifested in the confirmed correspondence of linkage groups with specific chromosomes. Applications include marker-assisted selection and breeding for yellow seeds.

SUBMITTER: Heneen WK

PROVIDER: S-EPMC3359914 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:BACKGROUND:The basic helix-loop-helix (bHLH) is the second largest gene family in the plant, some members play important roles in pistil development and response to drought, waterlogging, cold stress and salt stress. The bHLH gene family has been identified in many species, except for Brassica oleracea and B. napus thus far. This study aims to identify the bHLH family members in B. oleracea, B. rapa and B. napus, and elucidate the expression, duplication, phylogeny and evolution characters of them. RESULT:A total of 268 bHLH genes in B. oleracea, 440 genes in B. napus, and 251 genes in B. rapa, including 21 new bHLH members, have been identified. Subsequently, the analyses of the phylogenetic trees, conserved motifs and gene structures showed that the members in the same subfamily were highly conserved. Most Ka/Ks values of homologous gene were?<?1, which indicated that these genes suffered from strong purifying selection for retention. The retention rates of BrabHLH and BolbHLH genes were 51.6 and 55.1%, respectively. The comparative expression patterns between B. rapa and B. napus showed that they had similar expression patterns in the root and contrasting patterns in the stems, leaves, and reproductive tissues. In addition, there were 41 and 30 differential expression bHLH genes under the treatments of ABA and JA, respectively, and the number of down regulation genes was significantly more than up regulation genes. CONCLUSION:In the present study, we identified and performed the comparative genomics analysis of bHLH gene family among B. oleracea, B. rapa and B. napus, and also investigated their diversity. The expression patterns between B. rapa and B. napus shows that they have the similar expression pattern in the root and opposite patterns in the stems, leaves, and reproduction tissues. Further analysis demonstrated that some bHLH gene members may play crucial roles under the abiotic and biotic stress conditions. This is the first to report on the bHLH gene family analysis in B. oleracea and B. napus, which can offer useful information on the functional analysis of the bHLH gene in plants.