Department of Agricultural, Food, Environmental and Animal Sciences, University of Udine, Udine, Italy.
Department of Biotechnology, University of Verona, Verona, Italy.
Physiol Plant. 2022 Jan;174(1):e13607. doi: 10.1111/ppl.13607.
The low bioavailability of nutrients, especially nitrogen (N) and phosphorus (P), is one of the most limiting factors for crop production. In this study, under N- and P-free nutrient solution (-N-P), nodulating white lupin plants developed some nodules and analogous cluster root structures characterized by different morphological, physiological, and molecular responses than those observed upon single nutrient deficiency (strong acidification of external media, a better nutritional status than -N+P and +N-P plants). The multi-elemental analysis highlighted that the concentrations of nutrients in white lupin plants were mainly affected by P availability. Gene-expression analyses provided evidence of interconnections between N and P nutritional pathways that are active to promote N and P balance in plants. The root exudome was mainly characterized by N availability in nutrient solution, and, in particular, the absence of N and P in the nutrient solution triggered a high release of phenolic compounds, nucleosides monophosphate and saponines by roots. These morphological, physiological, and molecular responses result from a close interplay between N and P nutritional pathways. They contribute to the good development of nodulating white lupin plants when grown on N- and P-free media. This study provides evidence that limited N and P availability in the nutrient solution can promote white lupin-Bradyrhizobium symbiosis, which is favourable for the sustainability of legume production.
养分（尤其是氮（N）和磷（P））的生物利用度低是作物生产的最主要限制因素之一。在本研究中，在缺乏氮（-N-P）和磷（-N-P）的营养液中，结瘤的白 Lupinus 植物发育出一些根瘤和类似的簇状根结构，其形态、生理和分子响应与单一养分缺乏时观察到的不同（外部介质强烈酸化，营养状况优于 -N+P 和 +N-P 植物）。多元素分析强调，白 Lupinus 植物中的养分浓度主要受 P 供应的影响。基因表达分析提供了证据，证明 N 和 P 营养途径之间存在相互联系，这些途径活跃于促进植物体内 N 和 P 的平衡。根分泌物组主要受营养液中 N 供应的影响，特别是营养液中缺乏 N 和 P 会触发根大量释放酚类化合物、单核苷酸和皂甙。这些形态、生理和分子响应是由 N 和 P 营养途径之间的紧密相互作用引起的。它们有助于结瘤白 Lupinus 植物在缺乏 N 和 P 的培养基上的良好发育。本研究提供的证据表明，营养液中有限的 N 和 P 供应可以促进白 Lupinus-Bradyrhizobium 共生，这有利于豆科植物生产的可持续性。
