Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, 1-5 Hangi-cho, Shimogamo, Sakyo-ku, Kyoto 606-8522, Japan.
Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan.
Gene. 2021 Apr 15;776:145443. doi: 10.1016/j.gene.2021.145443. Epub 2021 Jan 21.
Two cultured cell lines (GTH4 and GTH4S) of a Nicotiana interspecific F hybrid (N. gossei × N. tabacum) were comparatively analyzed to find genetic factors related to hybrid inviability. Both cell lines proliferated at 37 °C, but after shifting to 26 °C, GTH4 started to die similar to the F hybrid seedlings, whereas GTH4S survived. As cell death requires de novo expression of genes and proteins, we compared expressed protein profiles between the two cell lines, and found that NgSGT1, a cochaperone of the chaperone complex (HSP90-SGT1-RAR1), was expressed in GTH4 but not in GTH4S. Agrobacterium-mediated transient expression of NgSGT1, but not NtSGT1, induced cell death in leaves of N. tabacum, suggesting its possible role in hybrid inviability. Cell death in N. tabacum was also induced by transient expression of NgRAR1, but not NtRAR1. In contrast, transient expression of any parental combinations of three components revealed that NgRAR1 promoted cell death, whereas NtRAR1 suppressed it in N. tabacum. A specific inhibitor of HSP90, geldanamycin, inhibited the progression of hypersensitive response-like cell death in GTH4 and leaf tissue after agroinfiltration. The present study suggested that components of the chaperone complex are involved in the inviability of Nicotiana interspecific hybrid.
两种烟草种间杂种（Nicotiana interspecific F hybrid）的细胞系（GTH4 和 GTH4S）被比较分析，以寻找与杂种不育相关的遗传因素。两种细胞系在 37°C 下均能增殖，但转移到 26°C 后，GTH4 开始像 F 杂种幼苗一样死亡，而 GTH4S 则存活下来。由于细胞死亡需要新基因和蛋白质的表达，我们比较了两种细胞系之间的表达蛋白谱，发现了 NgSGT1，一种伴侣复合物（HSP90-SGT1-RAR1）的共伴侣，在 GTH4 中表达，但在 GTH4S 中不表达。农杆菌介导的 NgSGT1 瞬时表达，而不是 NtSGT1，诱导了烟草叶片的细胞死亡，表明其可能在杂种不育中起作用。烟草叶片的细胞死亡也被 NgRAR1 瞬时表达诱导，但不是 NtRAR1。相比之下，三种成分的任何亲本组合的瞬时表达表明，NgRAR1 促进了细胞死亡，而 NtRAR1 则抑制了烟草中的细胞死亡。HSP90 的一种特异性抑制剂格尔德霉素（geldanamycin）抑制了 agroinfiltration 后 GTH4 和叶片组织中类似过敏反应的细胞死亡的进展。本研究表明，伴侣复合物的成分参与了烟草种间杂种的不育。
