In the present study, we identified and characterized two defensin-like peptides in an antifungal fraction obtained from Capsicum chinense pepper fruits and inhibited the growth of Colletotrichum scovillei, which causes anthracnose. AMPs were extracted from the pericarp of C. chinense peppers and subjected to ion exchange, molecular exclusion, and reversed-phase in a high-performance liquid chromatography system. We investigated the endogenous increase in reactive oxygen species (ROS), the loss of mitochondrial functioning, and the ultrastructure of hyphae. The peptides obtained from the G3 fraction through molecular exclusion chromatography were subsequently fractionated using reverse-phase chromatography, resulting in the isolation of fractions F1, F2, F3, F4, and F5. The F1-Fraction suppressed C. scovillei growth by 90, 70.4, and 44% at 100, 50, and 25 μg mL⁻¹, respectively. At 24 h, the IC₅₀ and minimum inhibitory concentration were 21.5 μg mL⁻¹ and 200 μg mL⁻¹, respectively. We found an increase in ROS, which may have resulted in an oxidative burst, loss of mitochondrial functioning, and cytoplasm retraction, as well as an increase in autophagic vacuoles. MS/MS analysis of the F1-Fraction indicated the presence of two defensin-like proteins, and we were able to identify the expression of three defensin sequences in our C. chinense fruit extract. The F1-Fraction was also found to inhibit the activity of insect α-amylases. In summary, the F1-Fraction of C. chinense exhibits antifungal activity against a major pepper pathogen that causes anthracnose. These defensin-like compounds are promising prospects for further research into antifungal and insecticide biotechnology applications. © 2024 Society of Chemical Industry.

中文翻译：

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辣椒中的防御素样肽可诱导 ROS 增加、线粒体功能丧失以及真菌炭疽菌 (Colletotrichum scovillei) 的生长减少

在本研究中，我们鉴定并表征了从辣椒果实中获得的抗真菌成分中的两种防御素样肽，并抑制了引起炭疽病的斯科氏炭疽病的生长。从辣椒果皮中提取 AMP ，并在高效液相色谱系统中进行离子交换、分子排除和反相。我们研究了活性氧（ROS）的内源性增加、线粒体功能的丧失以及菌丝的超微结构。随后使用反相色谱法对通过分子排阻色谱法从G3级分获得的肽进行分级，从而分离出级分F1、F2、F3、F4和F5。 F1-Fraction在 100、50 和 25 μg mL ^{-1浓度下分别抑制}斯科氏梭菌生长 90%、70.4% 和 44% 。 24小时时，IC ₅₀和最小抑制浓度分别为21.5 μg mL ^-1和200 μg mL ^-1。我们发现活性氧增加，这可能导致氧化爆发、线粒体功能丧失和细胞质收缩，以及自噬泡增加。 F1 级分的 MS/MS 分析表明存在两种防御素样蛋白，并且我们能够鉴定三种防御素序列在我们的中华果提取物中的表达。 F1-Fraction 还被发现可以抑制昆虫 α-淀粉酶的活性。总之，C. chinense的 F1 级分对引起炭疽病的主要辣椒病原体表现出抗真菌活性。这些防御素样化合物在抗真菌和杀虫剂生物技术应用的进一步研究中具有广阔的前景。 © 2024 化学工业协会。