Involvement of a truncated MADS-box transcription factor ZmTMM1 in root nitrate foraging

Abstract

Plants can develop root systems with distinct anatomical features and morphological plasticity to forage nutrients distributed heterogeneously in soils. Lateral root proliferation is a typical nutrient-foraging response to a local supply of nitrate, which has been investigated across many plant species. However, the underlying mechanism in maize roots remains largely unknown. Here, we report on identification of a maize truncated MIKC-type MADS-box transcription factor (ZmTMM1) lacking K- and C-domains, expressed preferentially in the lateral root branching zone and induced by the localized supply of nitrate. ZmTMM1 belongs to the AGL17-like MADS-box transcription factor family that contains orthologs of ANR1, a key regulator for root nitrate foraging in Arabidopsis. Ectopic overexpression of ZmTMM1 recovers the defective growth of lateral roots in the Arabidopsis anr1 agl21 double mutant. The local activation of glucocorticoid receptor fusion proteins for ZmTMM1 and an artificially truncated form of AtANR1 without the K- and C-domains stimulates the lateral root growth of the Arabidopsis anr1 agl21 mutant, providing evidence that ZmTMM1 encodes a functional MADS-box that modulates lateral root development. However, no phenotype was observed in ZmTMM1-RNAi transgenic maize lines, suggesting a possible genetic redundancy of ZmTMM1 with other AGL17-like genes in maize. A comparative genome analysis further suggests that a nitrate-inducible transcriptional regulation is probably conserved in both truncated and non-truncated forms of ZmTMM1-like MADS-box transcription factors found in grass species.

Comparative transcriptome analysis of flower bud transition and functional characterization of EjAGL17 involved in regulating floral initiation in loquat

“…However, fluorescence of 35S::EjAGL17-GFP was found only in the nucleus (Fig 8A). These results showed that EjAGL17 is a nuclear-localized protein and its subcellular localization pattern is consistent with that of AGL17 orthologs in soybean and maize [39,40], having subcellular localization characteristics of typical transcription factors.…”

“…In rice, AGL17 ortholog was mainly expressed in root development [52,53]. In maize, AGL17 ortholog was mainly expressed in root xylem parenchyma cells [40]. These data showed that expression patterns of AGL17 orthologs exhibit diverse in development process in angiosperm.…”

“…Function of AGL17 ortholog is involved in the regulation of root and seed development in rice, and participated in responses to osmotic stress and nutrient supply [ 52 – 54 ]. In maize, functional analysis of AGL17 ortholog suggests that its involvement in root nitrate-foraging [ 40 ]. These data revealed that characterization of AGL17 orthologs is involved in regulating different development aspects and functional diversification.…”

The Root Foraging Response under Low Nitrogen Depends on DWARF1-Mediated Brassinosteroid Biosynthesis

“…The ground-breaking work of Drew (1975) showed that plants can stimulate lateral root proliferation into N-rich patches where adequate amounts of nitrate or ammonium are available. More recent work has demonstrated that these two N forms act synergistically to regulate root system architecture, as localized ammonium provokes higher-order lateral root branching (Lima et al, 2010) while nitrate primarily stimulates lateral root elongation (Zhang and Forde, 1998;Remans et al, 2006;Guan et al, 2014;Liu et al, 2020). In the case of nitrate-driven lateral root elongation, underlying signaling pathways have been identified in which the nitrate transceptor NITRATE TRANSPORTER1.1 (NRT1.1) plays a dual role.…”

Insights into the genetic architecture of complex traits in Napier grass (Cenchrus purpureus) and QTL regions governing forage biomass yield, water use efficiency and feed quality traits

“…The genomic region spanning about 22 kbp at the bottom of A01 harbours QTLs controlling DM in all the three soil-moisture conditions. One of the markers was associated with a gene encoding a MADS-box transcription factor, which is a member of regulatory networks and governs diverse developmental processes in plants, including root development (Liu et al, 2020). A marker associated with IVOMD on A04 was co-localized with M28_161, which is a marker associated with high values of biomass digestibility in a previous study (Rocha et al, 2019).…”