Genome-Wide Identification of the Maize TALE Gene Family and Their Expression Analysis Under Low-Phosphorus Response in Maize (Zea mays L.)

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.