Introduction

Land plants have been intimately associated with fungi over the course of their evolution. Because of their lack of sophisticated protective structures, early land plants would conceivably have required additional defense strategies against microbial pathogens, including various fungi. On the other hand, a symbiotic association between plants and fungi is instrumental to plant adaptation to terrestrial environments (Selosse & Le Tacon, 1998; Bidartondo et al., 2011; Martin et al., 2017). The crucial role of this partnership is further evidenced by the widespread occurrence of mycorrhiza (root–fungi association) in vascular plants, as well as mycorrhiza‐like fungal associations (MFAs hereafter) in nonvascular plants, such as liverworts and hornworts (Wang & Qiu, 2006; Pressel et al., 2014). Surprisingly, although fungal symbiosis is commonly considered to be an ancestral trait for land plants (Wang & Qiu, 2006; Delaux et al., 2015), with the possible exception of the genus Takakia (Boullard, 1988; Grosche et al., 2018), no MFAs have been confirmed in other mosses (Pressel et al., 2014; Field et al., 2015), the most diverse group of nonvascular land plants.

Here, we report two genomic regions in the nuclear genome of the moss Physcomitrium patens, previously Physcomitrella patens (Medina et al., 2019; Rensing et al., 2020), that contain mostly fungi‐specific genes and mobile genetic elements. These two regions were identified in our genome screening for horizontally acquired genes in P. patens. Available evidence indicates that these fungi‐specific genes are probably involved in the interaction between mosses and fungi. We discuss how these fungi‐specific genes might have contributed to the defense against fungal and other microbial pathogens, as well as the loss of MFAs in mosses.

中文翻译：

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真菌衍生的基因组区域是否与对苔藓中真菌的拮抗作用有关？

介绍

陆地植物在进化过程中与真菌有着密切的联系。由于缺乏精密的保护结构，可以想象到，早期的陆地植物需要针对微生物病原体（包括各种真菌）的额外防御策略。另一方面，植物与真菌之间的共生联系有助于植物适应陆地环境（Selosse＆Le Tacon，1998 ; Bidartondo等，2011 ; Martin等，2017）。）。这种伙伴关系的关键作用进一步得到了证明，在维管植物中广泛存在菌根（根真菌结合体），以及在非维管植物中，如肝地黄和金缕梅（Wang＆Qiu ，2006； Pressel等，2014）。出人意料的是，虽然真菌的共生关系通常被认为是陆地植物的祖先性状（王＆秋，2006年; Delaux等人，2015年），与属可能是个例外藻苔属（Boullard，1988年; Grosche等人，2018），其他苔藓中也未确认MFA（Pressel等人，2014 ; Field等人，2015），这是最多样化的非维管陆地植物。

在这里，我们报告了苔藓Physcomitrium patens的核基因组中的两个基因组区域，即以前的Physcomitrella patens（Medina等人，2019 ; Rensing等人，2020），主要包含真菌特异性基因和可移动遗传元件。这两个区域在我们的基因组筛选中鉴定了P. patens中水平获取的基因。现有证据表明，这些真菌特异性基因可能与苔藓和真菌之间的相互作用有关。我们讨论了这些真菌特异性基因如何可能有助于防御真菌和其他微生物病原体，以及苔藓中MFA的损失。