Nuclear–Cytoplasmic Coevolution Analysis of RuBisCO in Synthesized Cucumis Allopolyploid

摘要

Allopolyploids are often faced with the challenge of maintaining well-coordination between nuclear and cytoplasmic genes inherited from different species. The synthetic allotetraploid is a useful model to explore cytonuclear coevolution. In this study, the sequences and expression of cytonuclear enzyme complex RuBisCO as well as its content and activity in were compared to its parents to explore plastid–nuclear coevolution. The plastome-coded gene sequence was confirmed to be stable maternal inheritance, and parental copy of nuclear genes were both preserved in Thus, the maternal plastid may interact with the biparentally inherited alleles. The expression of the gene of C-homoeologs (paternal) was significantly higher than that of H-homoeologs (maternal) in (HHCC). Protein interaction prediction analysis showed that the rbcL protein has stronger binding affinity to the paternal copy of rbcS protein than that of maternal copy in , which might explain the transcriptional bias of the homoeologs. Moreover, both the activity and content of RuBisCO in showed mid-parent heterosis. In summary, our results indicate a paternal transcriptional bias of the genes in , and we found new nuclear–cytoplasmic combination may be one of the reasons for allopolyploids heterosis.