College of Resources and Environment/National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, Huazhong Agricultural University, Wuhan 430070, China.
National Research Center for Geoanalysis/Key Laboratory of Eco-geochemistry, Ministry of Natural Resources, Beijing 100037, China.
J Agric Food Chem. 2024 Jul 31;72(30):16624-16637. doi: 10.1021/acs.jafc.4c02761. Epub 2024 Jul 17.
Selenium (Se) has been widely reported to affect plant growth, nutrient cycling, and the rhizobiome. However, how Se shapes the rhizobiome and interacts with plants remains largely elusive. Pot and hydroponic experiments were employed to elucidate the regulatory mechanism of Se in the citrus rhizobiome. Compared to the control, soil Se application significantly increased the root biomass (34.7%) and markedly reduced rhizosphere HCl-P, HO-P, NaHCO-IP, and residual-P of citrus, which were related to the variation of citrus rhizobiome. Se primarily enriched Proteobacteria and Actinobacteria as well as the phosphorus (P) functional genes and . Further study revealed that Se altered the metabolite profile of root exudate, particularly enhancing the abundance of l-cyclopentylglycine, cycloleucine, l-proline, l-pipecolic acid, and inositol, which played a key role in reshaping the citrus rhizobiome. These metabolites could serve as both nutrient sources and signaling molecules, thus supporting the growth or chemotaxis of the functional microbes. These bacterial taxa have the potential to solubilize P or stimulate plant growth. These findings provide a novel mechanistic understanding of the intriguing interactions between Se, root exudate, and rhizosphere microbiomes, and demonstrate the potential for utilizing Se to regulate rhizobiome function and enhance soil P utilization in citrus cultivation.
硒（Se）已被广泛报道影响植物生长、养分循环和根际微生物群落。然而，Se 如何塑造根际微生物群落并与植物相互作用在很大程度上仍不清楚。我们采用盆栽和水培实验来阐明 Se 对柑橘根际微生物群落的调控机制。与对照相比，土壤施硒显著增加了柑橘的根生物量（34.7%），并明显降低了柑橘根际 HCl-P、HO-P、NaHCO-IP 和残留-P，这与柑橘根际微生物群落的变化有关。Se 主要富集了变形菌门和放线菌门，以及磷（P）功能基因 和 。进一步研究表明，Se 改变了根分泌物的代谢物谱，特别是增强了 l-环戊基甘氨酸、环亮氨酸、l-脯氨酸、l-哌啶酸和肌醇的丰度，这些物质在重塑柑橘根际微生物群落中起着关键作用。这些代谢物既可以作为营养源，也可以作为信号分子，从而支持功能微生物的生长或趋化性。这些细菌类群具有溶解 P 或刺激植物生长的潜力。这些发现为 Se、根分泌物和根际微生物群落之间的有趣相互作用提供了一种新的机制理解，并展示了利用 Se 来调节根际微生物群落功能和提高柑橘栽培中土壤 P 利用率的潜力。
