Natural Product Aloesin Significantly Inhibits Spore Germination and Appressorium Formation in Magnaporthe oryzae

Guohui Zhang; Rongyu Li; Xiaomao Wu; Ming Li

doi:10.3390/microorganisms11102395

Natural Product Aloesin Significantly Inhibits Spore Germination and Appressorium Formation in Magnaporthe oryzae

Microorganisms. 2023 Sep 26;11(10):2395. doi: 10.3390/microorganisms11102395.

Authors

Guohui Zhang^{1

2}, Rongyu Li¹, Xiaomao Wu¹, Ming Li¹

Affiliations

¹ Institute of Crop Protection, College of Agriculture, Guizhou University, Guiyang 550025, China.
² College of Life and Health Science, Kaili University, Kaili 556000, China.

Abstract

This study aims to determine the effects of the natural product aloesin against Magnaporthe oryzae. The results exposed that aloesin had a high inhibitory effect on appressorium formation (the EC₅₀ value was 175.26 μg/mL). Microscopic examination revealed that 92.30 ± 4.26% of M. oryzae spores could be broken down by 625.00 μg/mL of aloesin, and the formation rate of appressoria was 4.74 ± 1.00% after 12 h. M. oryzae mycelial growth was weaker than that on the control. The enzyme activity analysis results indicated that aloesin inhibited the activities of polyketolase (PKS), laccase (LAC), and chain-shortening catalytic enzyme (Aayg1), which are key enzymes in melanin synthesis. The inhibition rate by aloesin of PKS, LAC, and Aayg1 activity was 32.51%, 33.04%, and 43.38%, respectively. The proteomic analysis showed that actin expression was downregulated at 175.62 μg/mL of aloesin, which could reduce actin bundle formation and prevent the polar growth of hyphae in M. oryzae. This is the first report showing that aloesin effectively inhibits conidia morphology and appressorium formation in M. oryzae.

Keywords: Magnaporthe oryzae; aloesin; appressorium formation; conidia; enzyme activity; proteomics.

Grants and funding

This study was supported by the National Natural Science Foundation of China (Nos. 32160657 and 32160658), the Cultivation Project of Guizhou University (No. [2019]43), the Science and Technology Foundation Project of Guizhou Province (No. 2017-1166), and the Professor Project of Kaili University (JS201603).