Genome-wide identification of phosphate transporter gene family in Trichoderma harzianum and expression in response to biotic and abiotic stress.

Phosphorus is an essential nutrient for organismal growth and development, and its absorption and transport primarily depend on the phosphate transporter (PHT) family. Although the functions of PHTs have been extensively studied in plants and algae, the researches on PHTs in microorganisms, particularly in Trichoderma species, remain limited. In this study, we identified 22 PHT family members in Trichoderma harzianum T-aloe through a genome-wide analysis. Phylogenetic analysis classified these members into three major clusters: Cluster I (8 members), Cluster II (12 members), and Cluster III (2 members). Furthermore significant differences among cluster members in gene structure, protein topology, subcellular localization, conserved motifs, and promoter cis-elements were revealed. Notably, the pronounced induction of all TrPHT genes under phosphate deficiency, coupled with their suppression under salt stress, suggests a finely-tuned regulatory mechanism that coordinates phosphate homeostasis with stress adaptation. In addition, TrPHT1/2/4/15/22 were induced in response to Fusarium graminearum stress. The TrPHT1/4/22 mutants exhibited significantly decreased total phosphorus content, accompanied by compromised antifungal efficacy against F. graminearum and reduced salt stress tolerance. Together, our results provide foundational insights into the PHT family in T. harzianum and demonstrate that TrPHTs are critical for maintaining phosphorus homeostasis and mediating responses to both biotic and abiotic stresses.