The three-amino-acid-loop-extension (TALE) gene family encodes a group of plant-specific homeodomain transcription factors that play indispensable roles in plant growth, development, and adaptation to environmental stresses. Although TALE genes have been extensively investigated in several plant species, their genome-wide characteristics and potential functions in maize, particularly in response to phosphorus deficiency, remain poorly understood. In the present study, a comprehensive genome-wide identification and characterization of the maize TALE gene family were conducted using bioinformatics approaches, followed by an investigation of their transcriptional responses to low-phosphorus (LP) stress. A total of 40 ZmTALE genes (ZmTALE1–ZmTALE40) were identified and phylogenetically classified into four subfamilies: BEL1-like, KNOX I, KNOX II, and KNOX III. Members within the same subfamily exhibited highly conserved gene structures and motif compositions, reflecting their evolutionary conservation. Chromosomal localization and synteny analyses demonstrated that segmental duplication has been the predominant force driving the expansion of the ZmTALE gene family during maize evolution. Promoter analysis revealed that the upstream regulatory regions of ZmTALE genes were enriched in light-responsive, phytohormone-responsive, and abiotic stress-related cis-acting regulatory elements, implying their potential involvement in multiple developmental and stress-responsive pathways. Expression profiling under LP conditions revealed pronounced genotype-dependent transcriptional responses among different maize inbred lines. Notably, ZmTALE1/5/12/14/18/30/31/33/36 were significantly induced by LP stress, whereas ZmTALE10 and ZmTALE37 were markedly repressed. These differentially expressed genes represent promising candidates for further functional investigation of phosphorus-deficiency tolerance in maize. Furthermore, ZmTALE10, ZmTALE14, and ZmTALE31 are nuclear-localized transcriptional activators. Taken together, these findings provide valuable insights into the evolutionary characteristics and potential biological functions of the maize TALE gene family and offer candidate genes for developing phosphorus-efficient maize cultivars through molecular breeding.

Cytokinin signaling is essential for plant growth, development, and responses to environmental stresses. As key transcription factors in this pathway, type-B response regulators (ARR-Bs) activate the expression of primary cytokinin-responsive genes. However, the systematic identification of the ARR-B family in maize and its functional roles in responses to phosphorus (P) nutritional stress remain largely unclear. In this study, the maize ARR-B (ZmARR-B) transcription factor family was systematically identified and comprehensively characterized at the genome-wide level. A total of 12 ZmARR-B genes were identified and comprehensively characterized in terms of chromosomal localization, physicochemical properties, protein structure, phylogenetic relationships, gene organization, conserved motifs, promoter cis-regulatory elements, and collinearity. Based on systematic measurements of leaf inorganic phosphate (Pi) concentrations in 70 maize inbred lines from southwestern China, the lines 082, B73, and Ye107 were selected as representative materials. By integrating long-term (14 d) and short-term (0.5–12 h) low-P treatments with transcriptome sequencing and qRT-PCR validation, we systematically characterized the expression dynamics of ZmARR-B family members under P deficiency. The results showed that ZmARR-B genes exhibited markedly differentiated low-P-responsive expression patterns among distinct genetic backgrounds. ZmARR-B03 was transiently induced during the early phase of low-P treatment (0–6 h), followed by a rapid decline in transcript abundance. This characteristic pulse-like expression pattern suggests that ZmARR-B03 may function as a rapid-response regulator during early P-starvation signal transduction. In contrast, ZmARR-B06 exhibited sustained transcriptional upregulation throughout the low-P treatment period, suggesting a potential role in long-term adaptive regulation under P-deficient conditions. Notably, the number of low-P-responsive ZmARR-B members was significantly greater in the P-efficient inbred line 082 than in the P-sensitive line Ye107, indicating that ZmARR-B-mediated P-starvation responses are strongly genotype dependent. This study provides an important foundation for elucidating the molecular mechanisms by which cytokinin signaling, through type-B ARRs, regulates phosphate nutritional adaptation in maize. It also identifies potential candidate genes for the genetic improvement of P-efficient maize germplasm.