Adaptative responses of Neurospora crassa by histidine kinases upon the attack of the arthropod Sinella curviseta.

Histidine kinases (HKs) are important sensor proteins in fungi and play an essential role in environmental adaptation. However, the mechanisms by which fungi sense and respond to fungivores attack via HKs are not fully understood. In this study, we utilized Neurospora crassa to investigate the involvement of HKs in responding to fungivores attack. We found that the 11 HKs in N. crassa not only affected the growth and development, but also led to fluctuations in antioxidant production. Ten mutants in the genes encoding HKs (except ∆phy1) showed increased production of reactive oxygen species (ROS), especially upon Sinella curviseta attack. The ROS burst triggered changes in conidia and perithecial beaks formation, as well as accumulation of β-glucan, ergothioneine, ergosterol, and carotenoids. β-glucan was increased in ∆hk9, ∆os1, ∆hcp1, ∆nik2, ∆sln1, ∆phy1 and ∆phy2 mutants compared to the wild-type strain. In parallel, ergothioneine accumulation was improved in ∆phy1 and ∆hk16 mutants and further increased upon attack, except in ∆os1 and ∆hk16 mutants. Additionally, fungivores attack stimulated ergosterol and dehydroergosterol production in ∆hk9 and ∆os1 mutants. Furthermore, deletion of these genes altered carotenoid accumulation, with wild-type strain, ∆hk9, ∆os1, ∆hcp1, ∆sln1, ∆phy2, and ∆dcc1mutants showing an increase in carotenoids upon attack. Taken together, HKs are involved in regulating the production of conidia and antioxidants. Thus, HKs may act as sensors of fungivores attack and effectively improve the adaptive capacity of fungi to environmental stimuli.