Comprehensive genome-wide expression analysis of NLP transcription factors elucidates their crucial role in enhancing nitrogen response in wheat (Triticum aestivum L.)

Plant specific transcription family NLP (NIN-like protein) represent a gene family essential for regulating plant physiological processes, particularly growth and nitrate-nitrogen response. This study investigated the characteristics and expression profiles of NLP genes in wheat. Thephylogenetic analysis, grouped 18 NLP found in the wheat genome into three clades. TaNLP genes share collinear relationships with rice and Arabidopsis NLPs as evidenced in comparative genomic analysis. Segmental duplications within the wheat genome is primarily responsible for the TaNLP family's expansion. In Protein network analysis TaNLP4 was identified as a hub gene, interacting with multiple other genes to coordinate nitrogen responses. Both low and optimal nitrate conditions were used to measure nitrate uptake in wheat roots and the expression patterns of TaNLP genes under these conditions. During the seedling stage, tissue-specific expression analysis revealed that close homologs of AtNLP7 such as TaNLP4 and TaNLP5 are highly expressed in both roots and leaves while TaNLP17 and TaNLP18 displayed preferential expression in roots. Additionally, TaNLP2 in root tissue was upregulated under low nitrate conditions. Most TaNLPs are predominantly expressed in leaves and showed positive responses to nitrate treatments. These findings highlight the characteristics properties and biological roles of TaNLP genes in wheat, offering potential insights into improving nitrogen use efficiency for sustainable wheat production without use of excessive fertilizers.