School of Biological Sciences, Washington State University, Vancouver, WA, USA.
Amsterdam Institute for Life and Environment, Vrije Universiteit Amsterdam, Amsterdam, Netherlands.
Nat Microbiol. 2024 Aug;9(8):1929-1939. doi: 10.1038/s41564-024-01762-2. Epub 2024 Aug 2.
Legumes are ecologically and economically important plants that contribute to nutrient cycling and agricultural sustainability, features tied to their intimate symbiosis with nitrogen-fixing rhizobia. Rhizobia vary dramatically in quality, ranging from highly growth-promoting to non-beneficial; therefore, legumes must optimize their symbiosis with rhizobia through host mechanisms that select for beneficial rhizobia and limit losses to non-beneficial strains. In this Perspective, we examine the considerable scientific progress made in decoding host control over rhizobia, empirically examining both molecular and cellular mechanisms and their effects on rhizobia symbiosis and its benefits. We consider pre-infection controls, which require the production and detection of precise molecular signals by the legume to attract and select for compatible rhizobia strains. We also discuss post-infection mechanisms that leverage the nodule-level and cell-level compartmentalization of symbionts to enable host control over rhizobia development and proliferation in planta. These layers of host control each contribute to legume fitness by directing host resources towards a narrowing subset of more-beneficial rhizobia.
豆类是具有生态和经济重要性的植物，它们有助于养分循环和农业的可持续性，这与它们与固氮根瘤菌的密切共生关系有关。根瘤菌在质量上差异很大，从高度促进生长到非有益；因此，豆类必须通过宿主机制优化与根瘤菌的共生关系，选择有益的根瘤菌并限制非有益菌株的损失。在本观点中，我们考察了解码宿主对根瘤菌控制所取得的相当大的科学进展，实证检验了分子和细胞机制及其对根瘤菌共生及其益处的影响。我们考虑了感染前的控制，这需要豆类产生和检测精确的分子信号，以吸引和选择相容的根瘤菌菌株。我们还讨论了感染后的机制，这些机制利用了共生体在结节水平和细胞水平上的分隔化，使宿主能够控制根瘤菌在植物体内的发育和增殖。这些宿主控制层通过将宿主资源引导到更有益的根瘤菌的缩小子集，从而促进豆科植物的适应性。
