LjAMT2;2 Promotes Ammonium Nitrogen Transport during Arbuscular Mycorrhizal Fungi Symbiosis in Lotus japonicus

Abstract

Arbuscular mycorrhizal fungi (AMF) are important symbiotic microorganisms in soil that engage in symbiotic relationships with legumes, resulting in mycorrhizal symbiosis. Establishment of strong symbiotic relationships between AMF and legumes promotes the absorption of nitrogen by plants. Ammonium nitrogen can be directly utilised by plants following ammonium transport, but there are few reports on ammonium transporters (AMTs) promoting ammonium nitrogen transport during AM symbiosis. Lotus japonicus is a typical legume model plant that hosts AMF. In this study, we analysed the characteristics of the Lotus japonicus ammonium transporter LjAMT2;2, and found that it is a typical ammonium transporter with mycorrhizal-induced and ammonium nitrogen transport-related cis-acting elements in its promoter region. LjAMT2;2 facilitated ammonium transfer in yeast mutant supplement experiments. In the presence of different nitrogen concentrations, the LjAMT2;2 gene was significantly upregulated following inoculation with AMF, and induced by low nitrogen. Overexpression of LjAMT2;2 increased the absorption of ammonium nitrogen, resulting in doubling of nitrogen content in leaves and roots, thus alleviating nitrogen stress and promoting plant growth.

Effects of arbuscular mycorrhizal fungi on nitrogen uptake in cotton (Gossypium hirsutumL.) under low-nitrogen conditions

“…This expands the range of root absorption and promotes the ability of the roots to absorb nitrogen directly. In addition, AMF hyphae absorbed more NO 3 - -N than NH 4 + -N, which is inconsistent with the results of previous studies showing that AMF prefer NH 4 + -N (Li et al ., 2013; Wang et al ., 2022). This may be related to the N preference of cotton in the study area.…”

Genome-wide identification, expression profiling, and functional analysis of ammonium transporter 2 (AMT2) gene family in cassava (Manihot esculenta crantz)

“…In order to understand the phylogenetic relationships of AMT2 proteins in different plant species, the sequences of AMT2 proteins from A. thaliana (Gazzarrini et al, 1999), rice (Oryza sativa) (Sonoda et al, 2003), soybean (Glycine max) (Kobae et al, 2010), maize (Zea mays) (Hui et al, 2022), and Lotus japonicus (Wang et al, 2022) were obtained from the previous study, and the sequences from Ricinus communis, belonging to Euphorbiaceae, were identified using the identification method for the cassava AMT2 gene family. Multiple sequence alignment using MUSCLE and default parameters was applied to evaluate the evolutionary relationship of MeAMT2s proteins in cassava (Edgar, 2004), and a neighbor-joining (NJ) phylogenetic tree was established based on the alignment utilizing the MEGA version X software (Kumar et al, 2018) with 1000 bootstrap replications.…”

“…GmAMT4.1 showed specific expression in arbusculated cortical cells and localized on the periarbuscular membrane (Kobae et al, 2010). The LjAMT2.2 gene was significantly upregulated when inoculating with arbuscular mycorrhizal fungi (AMF) (Wang et al, 2022). Phylogenetic relationship analysis showed that MeAMT2.2, MeAMT2.4, MeAMT2.7, GmAMT4.1, and LjAMT2.2 were all assigned to subgroup 3 (Figure 2).…”

Genome-wide analysis of 14-3-3 gene family in four gramineae and its response to mycorrhizal symbiosis in maize

“…Z m T u b u l i n (Zm00001d009780) and ZmGAPDH (Zm00001d049641) were used as the endogenous reference genes to standardize the relative expression levels of ZmGRF genes. Our previous published work provided extensive knowledge regarding qRT-PCR reactions (Wang et al, 2022). The 10 -(DCt/3) method was used to determine the relative gene expression levels (Li et al, 2005;Liao et al, 2014).…”