Genome-wide characterization of histidine kinase genes in Aciculosporium take and their potential roles in cytokinin sensing.

Histidine kinases (HKs) are critical receptors within two-component regulatory systems, helping fungi perceive environmental stimuli. However, the functions of the HKs gene family in Aciculosporium take, which mediates cytokinin (CKs) imbalance during bamboo witches' broom disease, and the mechanisms by which HKs respond to CKs and environmental stimuli remain unelucidated. This study identified 10 AtaHKs genes, categorizing them into 8 groups. Phylogenetic analysis across multiple species suggested that Group I AtaHKs were closely linked to plant pathogenicity. The promoter regions of AtaHKs genes contained enrichment cis-acting elements responsive to carbon catabolism and carbon catabolite repression. RT-qPCR analysis revealed that AtaHK4 expression varied significantly in response to CKs, whereas AtaHK10 was markedly expressed under NaCl stress. According to protein 3D structure simulations and molecular docking, we speculate that the GAF domain may be the functional region responsible for CKs sensing, though it remains untested. This study offers an in-depth analysis of the functional characteristics of the AtaHKs gene family in A. take, thereby enhancing the theoretical understanding of signal transduction mechanisms in plant-pathogen interactions. Additionally, it contributes to the conservation of bamboo forest resources and supports the sustainable development of the bamboo industry.