The use of Baby boom (Bbm) and Wuschel2 (Wus2) has made maize transformation more efficient across an increasingly wide range of inbreds. However, the benefits have come with the requirement of excising these transformation helper components to enable plant regeneration, which adds size to the T-DNA, and complexity to the transformation system. A new system with the advantages of smaller size and simplicity for the selectable marker gene-containing T-DNA is described. First, expression of Zm-Wus2 alone driven by the maize Pltp promoter (Zm-Pltp_pro), was determined to be sufficient to induce rapid somatic embryo formation from the scutella of maize immature embryos. It was also demonstrated that co-infecting with two strains of Agrobacterium, one with a Wus2 expression cassette, and the other with a combination of both selectable and visual marker cassettes, produced transformed T0 plants that contained only a single copy of the selectable marker T-DNA, without the integration of Wus2. Furthermore, the process was optimized by varying the ratio of the two Agrobacterium strains, and by modulating Wus2 expression to enable high-frequency recovery of selectable marker-containing T0 plants that did not contain Wus2. Several factors may have contributed to this outcome. Wus2 expression in localized cell(s) appeared to stimulate somatic embryogenesis in neighboring cells, including those that had integrated the selectable marker. In addition, in cells in which the Wus2 T-DNA did not integrate but the selectable marker T-DNA did, transient Wus2 expression stimulated somatic embryo formation and regeneration of stable T0 plants that contained the selectable marker. In addition, augmenting the Pltp promoter with three viral enhancer elements to increase Wus2 expression stimulated embryogenesis while precluding their regeneration. The phenomenon has now been designated as “altruistic transformation.”

使用的婴儿潮（BBM）和Wuschel2（WUS2）取得了玉米转化跨越日益广泛自交系更有效。但是，需要切除这些转化辅助成分以实现植物再生，这带来了好处，这会增加T-DNA的大小，并增加转化系统的复杂性。描述了一种新系统，该系统具有较小的尺寸和简化的含选择标记基因的T-DNA的优点。首先，由玉米Pltp启动子驱动的Zm-Wus2单独表达（Zm - Pltp _pro）被确定足以诱导从玉米未成熟胚的小cut快速体细胞胚形成。还证明了用两种农杆菌菌株共感染，一种用Wus2表达盒共同感染，另一种用选择性和可见标记盒的组合感染，产生了仅含有单拷贝的选择性标记T的转化的T0植物。-DNA，无需整合Wus2。此外，通过改变两种农杆菌菌株的比例，并通过调节Wus2表达来实现该过程的优化，从而可以高频回收不含Wus2的含有选择标记的T0植物。几个因素可能促成了这一结果。Wus2在局部细胞中的表达似乎刺激了邻近细胞的体细胞胚胎发生，包括那些已经整合了选择标记的细胞。此外，在其中Wus2 T-DNA不整合但选择标记T-DNA整合的细胞中，瞬时Wus2表达刺激了体细胞胚的形成和含有选择标记的稳定T0植物的再生。另外，用三种病毒增强子元件增强Pltp启动子以增加Wus2表达刺激了胚胎发生，同时阻止了它们的再生。现在，该现象被称为“利他转化”。