The evolutionary diversification of organisms is commonly pictured as following a bifurcating tree of life. As time passes, species divide and follow their own evolutionary path along separate branches. In this strict bifurcating tree scenario, any evolutionary novelty or innovation is restricted to the lineage in which it arose. However, it is well known that branches of the tree of life can be porous, with episodic or even frequent genetic exchanges between species. Hybridization is especially frequent in some groups of plants and allows various amounts of gene flow between closely related taxa (Goulet et al., 2017). While hybridization involves sexual reproduction, recent evidence indicates that genetic material is also transferred between distantly related plant species by means other than sexual reproduction in a process known as lateral gene transfer (LGT). The cases of LGT reported to date involve various groups of plants and donors from different parts of the plant phylogeny or different phyla (reviewed by Richardson and Palmer, 2007; Gao et al., 2014; Wickell and Li, 2020), and genes received from bacteria have even been linked to the emergence of land plants (Cheng et al., 2019). In this short essay, we discuss the potential impacts of these genetic transfers for our understanding of plant evolution. We focus on LGTs, because they are readily tractable for assessing the effect of reticulations on plant functional diversification. The impacts of hybridization and introgression are, however, similar and also briefly discussed.

生物的进化多样化通常被描绘成遵循分叉的生命之树。随着时间的流逝，物种沿着不同的分支分裂并遵循自己的进化路径。在这种严格的分叉方案中，任何进化上的新颖性或创新都仅限于其出现的世系。但是，众所周知，生命之树的分支可能是多孔的，物种之间发生了偶发性甚至频繁的遗传交换。杂交在某些植物群中尤其常见，并允许密切相关的类群之间发生各种数量的基因流动（Goulet等人，2017）。尽管杂交涉及有性繁殖，但最近的证据表明，遗传物质也通过有性繁殖以外的其他方式在远缘植物物种之间转移，这一过程称为侧向基因转移（LGT）。迄今为止报道的LGT病例涉及植物系统发育的不同部位或不同系统发育的不同种类的植物和供体（Richardson和Palmer，2007年综述； Gao等，2014年； Wickell和Li，2020年），并获得了基因细菌产生的细菌甚至与陆地植物的出现有关（Cheng等，2019）。在这篇短文中，我们讨论了这些遗传转移对我们对植物进化的理解的潜在影响。我们关注LGT，因为它们易于评估网状结构对植物功能多样化的影响。然而，杂交和渗入的影响是相似的，并且也进行了简要讨论。