Uncoupler SYP‐14288 inducing multidrug resistance of Phytophthora capsici through overexpression of cytochrome P450 monooxygenases and P‐glycoprotein

Abstract

BACKGROUND: Fungicide resistance has become a serious problem for different mode of action groups except for uncouplers, which makes their resistance mechanism a hot topic, which until now, has not been well clarified. SYP-14288, a newly developed diarylamine fungicide modeled on fluazinam, has shown good toxicity to both oomycete and fungus by the action of uncoupling. In this research, the resistance of Phytophthora capsici to SYP-14288 was studied to clarify the resistance mechanism of uncouplers.RESULTS: The toxicity tests of resistant strains against SYP-14288 showed multidrug resistance. The high-performance liquid chromatography (HPLC) results showed that resistant strains could efflux the fungicide, and this ability could be inhibited by the efflux pump inhibitor amitriptyline. The target protein of amitriptyline is P-glycoprotein (P-gp), which was overexpressed in resistant strains. Three products of nitrate reduction of SYP-14288 were detected and determined by HPLC-Q-TOF. Eight cytochrome P450 monooxygenase (P450) proteins were differentially involved in the reduction reaction.CONCLUSION: Both fungicide efflux and detoxification metabolism were involved in the resistance mechanisms of P. capsici to SYP-14288.

Unveiling Vacuolar H+-ATPase Subunit a as the Primary Target of the Pyridinylmethyl-Benzamide Fungicide, Fluopicolide

“…In particular, it was found that commercial anti-αβ-spectrin antibodies cross-reacted with elongation factor 2 and Hsp70 from Neurospora crassa and P. infestans, respectively , High-level resistance of phytopathogens to fungicides is generally caused by point mutations affecting the target protein; − protein overexpression and detoxification generally result in low levels of fungicide resistance . We therefore conducted a comprehensive phylogenetic search for spectrin-like proteins in oomycetes, resulting in the identification of Pc506502 in P.…”

“…In particular, it was found that commercial anti-αβspectrin antibodies cross-reacted with elongation factor 2 and Hsp70 from Neurospora crassa and P. infestans, respectively 35,26 High-level resistance of phytopathogens to fungicides is generally caused by point mutations affecting the target protein; 36−39 protein overexpression and detoxification generally result in low levels of fungicide resistance. 40 We therefore conducted a comprehensive phylogenetic search for spectrin-like proteins in oomycetes, resulting in the identification of Pc506502 in P. capsici, encoding Pcα-actinin. Despite manipulating the expression of Pcα-actinin, including knocking out the gene, the sensitivity of P. capsici to fluopicolide remained unchanged, and no point mutations were detected in the Pcα-actinin gene of resistant strains, thus excluding Pcα-actinin as the primary target of fluopicolide.…”

Target and non‐target site mechanisms of fungicide resistance and their implications for the management of crop pathogens

“…In a recent study, verapamil reverted the resistance of Candida albicans to fluconazole (FLC), showed synergism with FLC against Candida albicans , and reduced fungal recovery 87 . For Phytophthora capsici on pepper, verapamil had no inhibitory effect in resistant isolates 88 . However, the MDR isolates of Phytophthora capsici could be inhibited by the EPI amitriptyline, 88 which is one substrate of P‐gp belonging to the ABC transporter superfamily 89 .…”

“…For Phytophthora capsici on pepper, verapamil had no inhibitory effect in resistant isolates 88 . However, the MDR isolates of Phytophthora capsici could be inhibited by the EPI amitriptyline, 88 which is one substrate of P‐gp belonging to the ABC transporter superfamily 89 . In addition, amitriptyline can recover the activity of fluazinam, chlorothalonil, and oxathiapiprolin in Phytophthora capsici isolates 88 .…”

“…However, the MDR isolates of Phytophthora capsici could be inhibited by the EPI amitriptyline, 88 which is one substrate of P‐gp belonging to the ABC transporter superfamily 89 . In addition, amitriptyline can recover the activity of fluazinam, chlorothalonil, and oxathiapiprolin in Phytophthora capsici isolates 88 . For Alternaria alternata on tomato, zinc nanoparticles (ZnO‐NPs) are effective against boscalid‐resistant and ‐sensitive isolates and showed enhanced antifungal activity when applied in combination with boscalid or fluazinam (an ATP‐synthetase inhibitor) 90 .…”