Nitrogen-fixing microbial associations with cereals have been of intense interest for more than a century (Roesch et al., Plant Soil 2008;302:91–104; Triplett, Plant Soil 1996;186:29–38; Mus et al., Appl. Environ. Microbiol. 2016;82:3698–3710; Beatty and Good, Science 2011;333:416–417). A recent report demonstrated that an indigenous Sierra Mixe maize landrace, characterized by an extensive development of aerial roots that secrete large amounts of mucilage, can acquire 28–82% of its nitrogen from atmospheric dinitrogen (Van Deynze et al., PLoS Biol. 2018;16:e2006352). Although the Sierra Mixe maize landrace is unique in the large quantity of mucilage produced, other cereal crops secrete mucilage from underground and aerial roots and we hypothesize that this may represent a general mechanism for cereals to support associations with microbial diazotrophs. We propose a model for the association of nitrogen-fixing microbes with maize mucilage and identify the four main functionalities for such a productive diazotrophic association.

一个多世纪以来，固氮微生物与谷物的结合一直引起人们极大的兴趣（Roesch等人，Plant Soil 2008； 302：91-104； Triplett，Plant Soil 1996； 186：29-38； Mus等人，Appl。Environ。Microbiol。2016 ; 82：3698–3710; Beatty and Good，Science 2011; 333：416–417）。最近的一份报告表明，土著塞拉米什玉米地方品种的特征是气生根的广泛发育，其分泌大量的粘液，可以从大气中的二氧化氮中获取其28-82％的氮（Van Deynze等人，PLoS Biol。2018; 16：e2006352）。尽管Sierra Mixe玉米地方品种在产生的大量粘液中是独特的，但其他谷类作物从地下和气生根分泌粘液，我们推测这可能是谷物支持与微生物重氮营养相关联的一般机制。我们提出了固氮微生物与玉米粘液缔合的模型，并确定了这种生产性重氮营养缔合的四个主要功能。