Paternal chromosome elimination of inducer triggers induction of double haploids in Brassica napus

作者：Shihui Zhao, Liangjun Huang, Qing Zhang, Ying Zhou, Meicui Yang, Haoran Shi, Yun Li, Jin Yang, Chao Li, Xianhong Ge, Wanzhuo Gong, Jisheng Wang, Qiong Zou, Lanrong Tao, Zeming Kang, Zhuang Li, Chaowen Xiao, Qiong Hu, Shaohong Fu · 发表于：Frontiers in Plant Science · 年份：2023 · DOI：10.3389/fpls.2023.1256338 · 被引用次数：4 · 研究领域：Chromosomal and Genetic Variations、Plant tissue culture and regeneration、Plant Reproductive Biology

A synthetic octoploid rapeseed, Y3380, induces maternal doubled haploids when used as a pollen donor to pollinate plant. However, the mechanism underlying doubled haploid formation remains elusive. We speculated that double haploid induction occurs as the inducer line’s chromosomes pass to the maternal egg cell, and the zygote is formed through fertilization. In the process of zygotic mitosis, the paternal chromosome is specifically eliminated. Part of the paternal gene might have infiltrated the maternal genome through homologous exchange during the elimination process. Then, the zygote haploid genome doubles (early haploid doubling, EH phenomenon), and the doubled zygote continues to develop into a complete embryo, finally forming doubled haploid offspring. To test our hypothesis, in the current study, the octoploid Y3380 line was back bred with the 4122- cp4-EPSPS exogenous gene used as a marker into hexaploid Y3380- cp4-EPSPS as paternal material to pollinate three different maternal materials. The fertilization process of crossing between the inducer line and the maternal parent was observed 48 h after pollination, and the fertilization rate reached 97.92% and 98.72%. After 12 d of pollination, the presence of cp4-EPSPS in the embryo was detected by in situ PCR, and at 13–23 d after pollination, the probability of F 1 embryos containing cp4-EPSPS gene was up to 97.27%, but then declined gradually to 0% at 23–33 d. At the same time, the expression of cp4-EPSPS was observe...