Based on two coconut (Cocos nucifera L.) genome-wide investigation of NODULE-INCEPTION-like protein family: evolution and expression profiles during development and stress

NODULE-INCEPTION-Like Protein (NLP) is a plant-specific transcription factor that plays a crucial role in nitrate uptake and stress responses. However, studies of <i>NLP</i> gene family in coconut are lacking. In this study, 7 <i>NLP</i> genes in the <i>Aromatic Dwarf</i> and 6 <i>NLP</i> genes in <i>Hainan Tall</i> coconut varities were identified. Furthermore, protein interaction network analysis suggested that CnD-NLP3/4/5 and CnT-NLP3/4/5 potentially interact with NRG2, HRS1, and LBD37, which may significantly influence nitrogen utilization in coconut, analysis of the promoters of <i>CnD-NLPs</i> and <i>CnT-NLPs</i> revealed many cis-acting elements associated with abiotic stress responses. Additionally, expression profiling showed that <i>CnD-NLPs</i> and <i>CnT-NLPs</i> were mainly expressed in mature leaves. Moreover, qRT-PCR analysis demonstrated that all identified <i>CnD-NLPs</i> responded to nitrogen deficiency, drought, and salt stress. Specifically, <i>CnD-NLP5</i> may be a potentially critical gene in nitrogen deficiency responses, <i>CnD-NLP4/5/6</i> and <i>CnD-NLP1</i> may play a pivotal role in drought and salt stress response, respectively. And screening of homologous genes showed that <i>CnD-NLP5</i> and <i>AtNLP8</i>, <i>CnD-NLP4</i> and <i>AtNLP7</i>, <i>CnD-NLP1</i> and <i>OsNLP2</i> are homologous genes, with similar functions, further supporting their involvement in nitrogen deficiency, drought, and salt stress responses. These results lay the foundation for future research on the <i>NLPs</i> function and potential applications in coconut.