A putative transporter is essential for integrating nutrient and hormone signaling with lateral root growth and nodule development inMedicago truncatula

Abstract

SUMMARYLegume root architecture involves not only elaboration of the root system by the formation of lateral roots but also the formation of symbiotic root nodules in association with nitrogen-fixing soil rhizobia. The Medicago truncatula LATD/NIP gene plays an essential role in the development of both primary and lateral roots as well as nodule development. We have cloned the LATD/NIP gene and show that it encodes a member of the NRT1(PTR) transporter family. LATD/NIP is expressed throughout the plant. pLATD/NIP-GFP promoterreporter fusions in transgenic roots establish the spatial expression of LATD/NIP in primary root, lateral root and nodule meristems and the surrounding cells. Expression of LATD/NIP is regulated by hormones, in particular by abscisic acid which has been previously shown to rescue the primary and lateral root meristem arrest of latd mutants. latd mutants respond normally to ammonium but have defects in responses of the root architecture to nitrate. Taken together, these results suggest that LATD/NIP may encode a nitrate transporter or transporter of another compound.

Nitrate transporters: an overview in legumes

“…MtNPF1.7 is expressed in the tips of primary and lateral roots (including the root cap, meristem and proximal portion of the elongation zone) as well as in the nodule meristem (Fig. 4) (Yendrek et al 2010). Accordingly, MtNPF1.7 plays a role in perception of ABA (Yendrek et al 2010) and contributes to LR formation, nodule meristem development and primary root growth organization of the root tip (Veereshlingam et al 2004;Liang et al 2007).…”

“…4) (Yendrek et al 2010). Accordingly, MtNPF1.7 plays a role in perception of ABA (Yendrek et al 2010) and contributes to LR formation, nodule meristem development and primary root growth organization of the root tip (Veereshlingam et al 2004;Liang et al 2007). MtNPF1.7 expression is controlled by several hormones, in particular by ABA, but is not regulated by nitrate (Yendrek et al 2010).…”

“…Accordingly, MtNPF1.7 plays a role in perception of ABA (Yendrek et al 2010) and contributes to LR formation, nodule meristem development and primary root growth organization of the root tip (Veereshlingam et al 2004;Liang et al 2007). MtNPF1.7 expression is controlled by several hormones, in particular by ABA, but is not regulated by nitrate (Yendrek et al 2010). Interestingly, root development defect of mutants affected in MtNPF1.7 (noted latd) can be rescued by ABA addition (Liang et al 2007), indicating a positive role of ABA in the establishment, or the maintenance, of root meristem function (Fig.…”

“…In this species, nitrate has an inhibitory effect on primary root growth at low and high concentrations in two different ecotypes, A17 and R108 (Yendrek et al 2010;Morère-Le Paven et al 2011;Pellizzaro et al 2014). A quantitative genetic approach allowed us to identify a major QTL involved in the control of M. truncatula radicle elongation in post-germination phase in both N-free medium and medium supplied with 5 mM nitrate.…”

Identification of arbuscular mycorrhiza-inducible Nitrate Transporter 1/Peptide Transporter Family (NPF) genes in rice

“…Recently, the Arabidopsis NPF7.3/NRT1.5 was shown to be a K + transporter and to NO 3 − -dependently control K + homeostasis in shoots (Drechsler et al 2015;Li et al 2017). Other family members, for example, function as a NO 3 − excretion transporter or in actinorhizal and rhizobial N-fixing symbioses (Jeong et al 2004;Segonzac et al 2007;Yendrek et al 2010), whereas a role of NPF proteins in plant-AMF interactions has not been observed yet.…”