Abstract
The hybrid between Brassica napus and B. rapa displays obvious heterosis in both growth performance and stress tolerances. A comparative transcriptome analysis for B. napus (AnAnCC genome), B. rapa (ArAr genome), and its hybrid F1 (AnArC genome) was carried out to reveal the possible molecular mechanisms of heterosis at the gene expression level. A total of 40,320 nonredundant unigenes were identified using B. rapa (AA genome) and B. oleracea (CC genome) as reference genomes. A total of 6,816 differentially expressed genes (DEGs) were mapped in the A and C genomes with 4,946 DEGs displayed nonadditively by comparing the gene expression patterns among the three samples. The coexistence of nonadditive DEGs including high-parent dominance, low-parent dominance, overdominance, and underdominance was observed in the gene action modes of F1 hybrid, which were potentially related to the heterosis. The coexistence of multiple gene actions in the hybrid was observed and provided a list of candidate genes and pathways for heterosis. The expression bias of transposable element-associated genes was also observed in the hybrid compared to their parents. The present study could be helpful for the better understanding of the determination and regulation of mechanisms of heterosis to aid Brassica improvement.
Highlights
IntroductionApproaches to increase the genetic variation of rapeseed have been made by introducing the genetic components from related species as B. napus can cross with one of its ancestral parents, B. rapa, to produce viable interspecies hybrids [4]
Brassica napus is one of the main oil crops used for human consumption and is widely grown in China, Canada, Europe, and Australia and increasingly grown in South America [1]
We identified several lines which displayed high yield up to 4,500 kg per hectare in BC1F2 population. It suggested that the novel lines from interspecific hybridization between B. napus and B. rapa with high yield good quality can be potentially useful for oilseeds production in the near future
Summary
Approaches to increase the genetic variation of rapeseed have been made by introducing the genetic components from related species as B. napus can cross with one of its ancestral parents, B. rapa, to produce viable interspecies hybrids [4]. Due to the high crossability between B. napus and B. rapa, and low aneuploidy of their interspecific hybrids, different B. rapa accessions have been widely hybridized to rapeseed breeding program and novel agronomic traits from B. rapa have been successfully transmitted into commercial B. napus varieties [5]. Strong heteroses affecting both biomass and seed yield have been observed in hybrids derived from these interspecific crosses [6]. The genetic and molecular mechanism of heterosis in the interspecific hybrids has not been investigated
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
