Herbicide pretilachlor impairs biofertilizer potential of Anabaena doliolum: Integrating proteomic responses,...

This study investigated proteomic alterations in Anabaena doliolum, a diazotrophic cyanobacterium native to Indian paddy fields, to elucidate the molecular basis of herbicide pretilachlor toxicity/tolerance. Proteomic analysis identified 325 proteins, with 124, 149, 179 and 190 proteins expressed at pretilachlor concentrations of 0 (control), 2, 5 and 10 μg/ml, respectively. At 2, 5 and 10 μg/ml, 67, 67 and 71 differentially expressed proteins were identified, involved in photosynthesis, carbon and nitrogen metabolism, protein synthesis, and redox homeostasis. Nitrogen fixation and heterocyst differentiation proteins displayed dose-dependent inhibition, except for slight induction at low dosages. Nitrogenase activity and heterocyst frequency observations further evidenced strong dose-dependent inhibition of nitrogen fixation and heterocyst differentiation. Transcript analysis revealed increased expression of sodA, sodB, and alr3090 at 2-10 μg/ml, with a notable decrease at 20 μg/ml. Molecular docking with pretilachlor yielded relative energy, LibDock scores with hotspot regions of interacting residues. FTIR spectroscopy exhibited alterations in the lipid profile due to oxidative membrane damage and adaptive measures. These findings dissect Anabaena doliolum's response mechanism to pretilachlor toxicity and provide a valuable reference for evaluating the potential risk posed by pretilachlor to native natural biofertilizers in paddy fields.