Antifungal activity of rapamycin on Botryosphaeria dothidea and its effect against Chinese hickory canker

Abstract

BACKGROUND: The trunk canker caused by Botryosphaeria dothidea is a devastating disease for Chinese hickory (Carya cathayensis) in China. Chemical fungicides are commonly and repeatedly applied to control the disease; however, fungicide application raises major environmental and food safety issues. Ecofriendly biocontrol alternatives were urgently needed. Herein, the antifungal activity of a natural secondary metabolite, rapamycin, against B. dothidea and the effect of a rapamycin-producing Streptomyces hygroscopicus on C. cathayensis canker were investigated. RESULTS: The 50% effective concentrations (EC 50) of rapamycin against mycelial growth and spore germination on the potato dextrose agar were 5.1 × 10 −3 and 5.5× 10 −2 ∼g mL-1 , respectively, which were much lower than the EC 50 values of thiophanate-methyl. The hyphae of B. dothidea exhibited premature aging and wrinkling after treatment with rapamycin at 5.0 × 10 −3 ∼g mL-1. A rapamycin-producing bacterium S. hygroscopicus LYJ637 was batch produced and formulated in a carboxymethylcellulose/poly (vinyl alcohol) (CMC/PVA) blend and used for testing the efficiency of the bacterium in controlling Botryosphaeria canker in C. cathayensis. S. hygroscopicus exhibited high stability in the CMC/PVA blend. Results of a 3-year field experiment suggested that rapamycin formation reduced the occurrence of both developed cankers and new cankers, with an efficacy comparable to the treatment with thiophanate-methyl. CONCLUSION: The rapamycin-producing S. hygroscopicus LYJ637 carried in a CMC/PVA blend prevented effectively Botryosphaeria canker on Chinese hickory, which provides an alternative approach to chemical control strategies.

Actinomycins produced by endophyte Streptomyces sp. GLL‐9 from navel orange plant exhibit high antimicrobial effect against Xanthomonas citri susp. citri and Penicillium italicum

“…47,48 It was reported that the primary microorganism responsible for the production of antibiotics is Streptomyces. 49 The Streptomyces species was widely used for the production of some antibiotics such as rapamycin 50 and avermectin, 51 and both of them were effective in controlling pests and diseases in agricultural crops. Act-X 2 , Act D, and Act-X O⊎ were the three main compounds isolated from the EAE of Streptomyces sp.…”

Honokiol inhibits Botryosphaeria dothidea, the causal pathogen of kiwifruit soft rot, by targeting membrane lipid biosynthesis

“…The primary method of controlling this disease still involves chemicals, which entails risk when they are used improperly. Hence, it is crucial to embrace novel and 27 curcumin, 28 rapamycin, 29 and natamycin. 30 Honokiol, a plantderived antimicrobial substance, has promising applications in agriculture, fishery, medicine, and related fields.…”

“…So far, several extracts from plants or microorganisms have been discovered to exhibit a potent inhibitory effect on B. dothidea . Examples include carvacrol, 27 curcumin, 28 rapamycin, 29 and natamycin 30 . Honokiol, a plant‐derived antimicrobial substance, has promising applications in agriculture, fishery, medicine, and related fields.…”

Astragalus–Scorpion Drug Pair Inhibits the Development of Prostate Cancer by Regulating GDPD4-2/PI3K/AKT/mTOR Pathway and Autophagy

“…Rapamycin is a macrolide that is originally developed as an antifungal agent ( Jiang et al, 2021 ). Rapamycin is useful in the treatment of various cancers due to its inhibitory effect on the PI3K/AKT/mTOR pathway ( Alzahrani, 2019 ).…”