Centre for Integrative Legume Research, School of Agriculture and Food Sciences, The University of Queensland, Brisbane, Australia.
National Navel Orange Engineering Research Center, College of Life and Environmental Science, Gannan Normal University, Ganzhou, China.
Plant Cell Environ. 2019 Jan;42(1):41-51. doi: 10.1111/pce.13348. Epub 2018 Jun 21.
Global demand to increase food production and simultaneously reduce synthetic nitrogen fertilizer inputs in agriculture are underpinning the need to intensify the use of legume crops. The symbiotic relationship that legume plants establish with nitrogen-fixing rhizobia bacteria is central to their advantage. This plant-microbe interaction results in newly developed root organs, called nodules, where the rhizobia convert atmospheric nitrogen gas into forms of nitrogen the plant can use. However, the process of developing and maintaining nodules is resource intensive; hence, the plant tightly controls the number of nodules forming. A variety of molecular mechanisms are used to regulate nodule numbers under both favourable and stressful growing conditions, enabling the plant to conserve resources and optimize development in response to a range of circumstances. Using genetic and genomic approaches, many components acting in the regulation of nodulation have now been identified. Discovering and functionally characterizing these components can provide genetic targets and polymorphic markers that aid in the selection of superior legume cultivars and rhizobia strains that benefit agricultural sustainability and food security. This review addresses recent findings in nodulation control, presents detailed models of the molecular mechanisms driving these processes, and identifies gaps in these processes that are not yet fully explained.
全球对增加粮食产量和减少农业合成氮肥投入的需求，推动了人们对豆科作物的使用。豆科植物与固氮根瘤菌之间的共生关系是其优势的核心。这种植物-微生物的相互作用导致了新的根器官的形成，称为根瘤，根瘤菌将大气中的氮气转化为植物可以利用的氮的形式。然而，根瘤的形成和维持是一个资源密集型的过程；因此，植物严格控制形成根瘤的数量。在有利和有压力的生长条件下，植物使用多种分子机制来调节根瘤的数量，使植物能够在各种情况下节约资源并优化发育。利用遗传和基因组方法，现在已经确定了许多在调节结瘤过程中起作用的成分。发现和功能表征这些成分可以提供遗传靶标和多态性标记，有助于选择优良的豆科作物品种和根瘤菌菌株，从而促进农业的可持续性和粮食安全。本文综述了近年来在结瘤控制方面的发现，提出了驱动这些过程的分子机制的详细模型，并指出了这些过程中尚未完全解释的空白。
