Rooting for nitrates: ZmNLP3.2 positively regulates root biomass under low nitrogen conditions through ZmAux/IAA14 inhibition

Plant roots are essential for resource uptake and anchorage to the soil.Root growth is dynamic, and can be adjusted according to a plant's needs.For example, in the case of low nutrient availability root growth can be promoted as a foraging response (Lynch 2019).Maize (Zea mays) possesses a primarily shoot-borne root system comprised of primary roots, seminal roots, crown roots, and lateral roots, which altogether contribute to successful plant growth (Hochholdinger 2009).Nitrogen (N) is an essential macronutrient for which sensing and uptake through the roots is partially regulated by NODULE INCEPTION (NIN)-like proteins (NLPs).These NLPs bind nitrate and activate many downstream genes related to N signaling and assimilation (Cao et al. 2017).Despite their relevance, it remains unclear how NLPs contribute to root development mechanistically.Auxins are well-known hormones involved in almost all aspects of root growth and development (Roychoudhry and Kepinski, 2022).However, no direct connection between NLPs and auxins in maize has been reported so far.