Beals T P, Goldberg R B
Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles 90095-1606, USA.
Plant Cell. 1997 Sep;9(9):1527-45. doi: 10.1105/tpc.9.9.1527.
We utilized a new cell ablation strategy to ablate specific anther cell types involved in the dehiscence process. The tobacco TA56 gene promoter is active within the circular cell cluster, stomium, and connective regions of the anther at different developmental stages. We introduced a cytotoxic TA56/barnase gene into tobacco plants together with three different anticytotoxic barstar genes. The anticytotoxic barstar genes were used to protect subsets of anther cell types from the cytotoxic effects of the TA56/barnase gene. The chimeric barstar genes were fused with (1) the tobacco TP12 gene promoter that is active at high levels in most anther cell types; (2) the soybean lectin gene promoter that is active earlier in the connective, and at lower levels in the circular cell cluster and stomium, than is the TA56 promoter; and (3) the tobacco TA20 gene promoter that is active at high levels in most anther cell types but has a different developmental profile than does the TP12 promoter. Normal anther development and dehiscence occurred in plants containing the TA56/barnase and TP12/barstar genes, indicating that barstar protects diverse anther cell types from the cytotoxic effects of barnase. Anthers containing the TA56/barnase and lectin/barstar genes also developed normally but failed to dehisce because of extensive ablation of the circular cell cluster, stomium, and contiguous connective regions. Anthers containing the TA56/barnase and TA20/barstar genes failed to dehisce as well. However, only the stomium region was ablated in these anthers. The connective, circular cell cluster, and adjacent wall regions were protected from ablation by the formation of barnase/barstar complexes. We conclude that anther dehiscence at flower opening depends on the presence of a functional stomium region and that chimeric barnase and barstar genes containing promoters that are active in several overlapping cell types can be used for targeted cell ablation experiments.
我们采用了一种新的细胞消融策略来消融参与开裂过程的特定花药细胞类型。烟草TA56基因启动子在花药不同发育阶段的圆形细胞簇、裂口和连接区域内具有活性。我们将细胞毒性TA56/芽孢杆菌RNA酶基因与三种不同的抗细胞毒性芽孢杆菌RNA酶抑制剂基因一起导入烟草植株。抗细胞毒性芽孢杆菌RNA酶抑制剂基因用于保护花药细胞类型的亚群免受TA56/芽孢杆菌RNA酶基因的细胞毒性作用。嵌合芽孢杆菌RNA酶抑制剂基因与以下基因融合：（1）烟草TP12基因启动子，在大多数花药细胞类型中高水平活跃；（2）大豆凝集素基因启动子，其在连接组织中比TA56启动子更早活跃，在圆形细胞簇和裂口中活性较低；（3）烟草TA20基因启动子，在大多数花药细胞类型中高水平活跃，但具有与TP12启动子不同的发育模式。含有TA56/芽孢杆菌RNA酶和TP12/芽孢杆菌RNA酶抑制剂基因的植株花药正常发育并开裂，表明芽孢杆菌RNA酶抑制剂可保护多种花药细胞类型免受芽孢杆菌RNA酶的细胞毒性作用。含有TA56/芽孢杆菌RNA酶和凝集素/芽孢杆菌RNA酶抑制剂基因的花药也正常发育，但由于圆形细胞簇、裂口和相邻连接区域的广泛消融而未能开裂。含有TA56/芽孢杆菌RNA酶和TA20/芽孢杆菌RNA酶抑制剂基因的花药也未能开裂。然而，这些花药中只有裂口区域被消融。连接组织、圆形细胞簇和相邻壁区域通过形成芽孢杆菌RNA酶/芽孢杆菌RNA酶抑制剂复合物而免受消融。我们得出结论，开花时花药开裂取决于功能性裂口区域的存在，并且含有在几种重叠细胞类型中活跃的启动子的嵌合芽孢杆菌RNA酶和芽孢杆菌RNA酶抑制剂基因可用于靶向细胞消融实验。
