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Rice blast disease, caused by Magnaporthe oryzae, is the most devastating cereal killer worldwide. Note that melanin pigment is an essential factor of M. oryzae virulence, thus fungicides interfering with melanin biosynthesizing enzymes would reduce the pathogenicity. Scytalone dehydratase (SDH) is the key target for commercial fungicides, like carpropamid, due to its role in the dehydration reaction of the fungal melanin pathway. However, a single-point mutation (V75M) in SDH elicits resistance to carpropamid. A lack of effective fungicides against this resistant strain expedited the quest for novel bioactive inhibitors. Currently, bacterial endophytes like Streptomyces have been heralded for synthesizing bioactive metabolites to protect plants from phytopathogens. The literature search led to the identification of 21 Streptomyces spp. symbionts of paddy that can suppress M. oryzae growth. An antiSMASH server was used to explore Streptomyces spp. gene clusters and found 4463 putative metabolites. Besides, 745 unique metabolites were subjected to a series of virtual screening techniques. Ideally, this process identified five potential SDH inhibitors. The docking result highlights that the metabolite pseudopyronine A interacted hydrophobically with both Val75 of SDHWT and Met75 of SDHV75M targets. Moreover, pseudopyronine A has a higher binding free energy with SDHWT (− 89.94 kcal/mol) and SDHV75M (− 71.95 kcal/mol). Interestingly, the pyranones scaffold of pseudopyronine A was reported for antifungal activity against phytopathogens. Dynamic behavior confirms that pseudopyronine A has excellent conformational states with both SDHWT and SDHV75M. Altogether, we hope that this study creates a new avenue for the discovery of novel phytopathogen inhibitors from endophytes. [ABSTRACT FROM AUTHOR]

Paddy (Oryza sativa) yield is greatly influenced by the insidious presence of rice-mimicking weed, widely known as barnyard grass. This study explores the promising natural ACCase inhibitors that could enhance paddy yield by controlling weeds. A total of 2828 natural compounds were examined using diverse computational techniques. The results of this study depict that CNP0390839 (xanthoangelol) exhibited a better XP Gscore (−7.328 kcal/mol) and MM/GBSA score (−84.24 kcal/mol) than other investigated compounds. Importantly, ACCase-xanthoangelol complexes was thermodynamically stable with an RMSD value of ∼1.2 nm. Of note, 72% xanthoangelol resides in the Angelica keiskei plant root which exhibits 55% weed-inhibitory action. The A. keiskei plant mainly inhibits the hypocotyl (71.8 ± 5.4%) and root region (55.3 ± 4.7%) of weeds. Moreover, the existence of dihydroxyphenyl scaffold in xanthoangelol was also witnessed in literatures for weed inhibitory action. Overall, xanthoangelol might prove to be an effective ACCase herbicide in paddy weed management. [ABSTRACT FROM AUTHOR]