Interspecific hybridization, polyploidization and backcross of Brassica oleracea var. alboglabra with B. rapa var. purpurea morphologically recapitulate the evolution of Brassica vegetables

Abstract

Brassica oleracea and B. rapa are two important vegetable crops. Both are composed of dozens of subspecies encompassing hundreds of varieties and cultivars. Synthetic B. napus with these two plants has been used extensively as a research model for the investigation of allopolyploid evolution. However, the mechanism underlying the explosive evolution of hundreds of varieties of B. oleracea and B. rapa within a short period is poorly understood. In the present study, interspecific hybridization between B. oleracea var. alboglabra and B. rapa var. purpurea was performed. The backcross progeny displayed extensive morphological variation, including some individuals that phenocopied subspecies other than their progenitors. Numerous interesting novel phenotypes and mutants were identified among the backcross progeny. The chromosomal recombination between the A and C genomes and the chromosomal asymmetric segregation were revealed using Simple Sequence Repeats (SSR) markers. These findings provide direct evidence in support of the hypothesis that interspecific hybridization and backcrossing have played roles in the evolution of the vast variety of vegetables among these species and suggest that combination of interspecific hybridization and backcrossing may facilitate the development of new mutants and novel phenotypes for both basic research and the breeding of new vegetable crops.

Polyploidy and the relationship between leaf structure and function: implications for correlated evolution of anatomy, morphology, and physiology in Brassica

“…These results indicate that ploidy level can affect both leaf morphological and anatomic structures as well as physiological function. Our results are congruent with studies of newly re-synthesized allotetraploid B. napus, which demonstrate 70% of life history traits differ from the parental diploids [51], and which indicate that aspects of leaf morphology can exhibit transgressive phenotypes [52, 53]. …”

Genomic Identification and Comparative Expansion Analysis of the Non-Specific Lipid Transfer Protein Gene Family in Gossypium

“…As a prominent mode of speciation in flowering plants, allopolyploidy can cause genomic changes, including chromosomal rearrangements and changes in gene expression45464748. Recent studies have indicated the unequal expression of orthologous genes in allotetraploids such as Gossypium 1349, Brassica 47, Oryza minuta 50 and the synthetic allopolyploid Arabidopsis51, and the gene expression levels in these allopolyploids deviated from the expression of their orthologous genes in the progenitors.…”

“…Recent studies have indicated the unequal expression of orthologous genes in allotetraploids such as Gossypium 1349, Brassica 47, Oryza minuta 50 and the synthetic allopolyploid Arabidopsis51, and the gene expression levels in these allopolyploids deviated from the expression of their orthologous genes in the progenitors. In our study, the expression patterns of genes in G. hirsutum revealed considerable differences from the expression of their orthologous genes in its progenitors (Fig.…”

Phenotypic and seed structural comparison in hybrids of different Brassica rapa and B. oleracea

“…'Yangyou6'. PCR analysis on S0 and S1 generation was performed using SSR primers in Table (Zhang et al, ). The young flower buds (~2 mm) of S0 generation were collected and fixed in Carnoy's solution (3:1 ethanol:acetic acid, v/v) for 24 hr, and then stored in 70% ethanol at 4℃.…”