图1. 苹果果实成熟期QTL标记加密与MdNAC18编码区遗传变异鉴定及其对表型的贡献
Y1H、EMSA、GUS报告基因和瞬时转化‘金冠’苹果试验证实MdNAC18能通过直接结合靶基因MdACO1、MdARF5和MdNAC18的启动子正调控其转录。前人文献报道MdARF5正调控MdACS1转录。MdNAC18的SNP517 T和SNP958 A等位变异降低了MdNAC18对靶基因MdACO1、MdARF5以及MdNAC18的启动子的激活作用。而MdARF5的下调表达降低了MdACS1和MdACO1的转录水平,最终表现为乙烯释放速率降低,果实成熟期较晚。MdACO1启动子上SNP1229 T破坏了NAC-core motif “ATGCGTG”,导致不能与MdNAC18转录因子结合,进而导致MdACO1的转录水平下降,最终也表现为乙烯释放速率降低和果实晚熟。另外发现文献报道的MdACO1编码区的62 bp碱基缺失 (InDel62) 特异性差,本研究重新开发了特异性引物,可直接用于MdACO1 InDel62基因型的快速PCR检测。MdNAC18的SNP517和SNP958,MdACO1的SNP1229和InDel62,以及MdACS1的InDel162等5个功能变异构成了一个复杂的遗传变异网络,精准调控苹果果实成熟期的表型变异 (图2)。
图2. 苹果果实成熟期的遗传变异网络模型示意图
图3. SNP517/SNP958/SNP152/SNP769/InDel162基因型组合效应值估算及苹果果实成熟期基因组辅助预测 (GAP) 模型的构建
参考文献:
Migicovsky, Z., Yeats, T.H., Watts, S., Song, J., Forney, C.F., Burgher-MacLellan, K., Somers, D.J., Gong, Y., Zhang, Z., Vrebalov, J., van Velzen, R., Giovannoni, J.G., Rose, J.K.C., and Myles, S. (2021). Apple ripening is controlled by a NAC transcription factor. Front Genet. 12: 671300.
Shen, F., Bianco, L., Wu, B., Tian, Z., Wang, Y., Wu, T., Xu, X., Han, Z., Velasco, R., Fontana, P., and Zhang, X. (2022). A bulked segregant analysis tool for out-crossing species (BSATOS) and QTL-based genomics-assisted prediction of complex traits in apple. J Adv Res. 42: 149–162.
文章引用:
Wen, G., Wu, B., Wang, Y., Wu, T., Han, Z., and Zhang, X. (2024). Natural variations in MdNAC18 exert major genetic effect on apple fruit harvest date by regulating ethylene biosynthesis genes. J. Integr. Plant Biol. https://doi.org/10.1111/jipb.13757
往期合集:
物种研究合集:
长按二维码
关注JIPB