Changes in the Plant β-Sitosterol/Stigmasterol Ratio Caused by the Plant Parasitic Nematode Meloidogyne incognita

Abstract

Sterols play a key role in various physiological processes of plants. Commonly, stigmasterol, β-sitosterol and campesterol represent the main plant sterols, and cholesterol is often reported as a trace sterol. Changes in plant sterols, especially in β-sitosterol/stigmasterol levels, can be induced by different biotic and abiotic factors. Plant parasitic nematodes, such as the root-knot nematode Meloidogyne incognita, are devastating pathogens known to circumvent plant defense mechanisms. In this study, we investigated the changes in sterols of agricultural important crops, Brassica juncea (brown mustard), Cucumis sativus (cucumber), Glycine max (soybean), Solanum lycopersicum (tomato) and Zea mays (corn), 21 days post inoculation (dpi) with M. incognita. The main changes affected the β-sitosterol/stigmasterol ratio, with an increase of β-sitosterol and a decrease of stigmasterol in S. lycopersicum, G. max, C. sativus and Z. mays. Furthermore, cholesterol levels increased in tomato, cucumber and corn, while cholesterol levels often were below the detection limit in the respective uninfected plants. To better understand the changes in the β-sitosterol/stigmasterol ratio, gene expression analysis was conducted in tomato cv. Moneymaker for the sterol 22C-desaturase gene CYP710A11, responsible for the conversion of β-sitosterol to stigmasterol. Our results showed that the expression of CYP710A11 was in line with the sterol profile of tomato after M. incognita infection. Since sterols play a key role in plant-pathogen interactions, this finding opens novel insights in plant nematode interactions.

Phytosterols in Seaweeds: An Overview on Biosynthesis to Biomedical Applications

“…The biosynthesis of phytosterol exhibits a parallel pathway of cholesterol synthesis in eukaryotic cells [ 24 ]; 2, 3-oxidosqualene serves as a common precursor for all sterol synthesis i.e., sterols like cholesterol in humans, ergosterol in fungi and phytosterols in plants. The biosynthesis of cholesterol and ergosterol is catalyzed by lanosterol synthase (LAS), whereas phytosterol synthesis from oxidosqualene is catalyzed by cycloartenol synthase (CAS) [ 25 ]. As in plant species, seaweeds metabolize 2, 3-oxidosqualene to phytosterol by CAS and exhibit the hybrid cholesterol pathway as well, indicating an evolutionary relationship between these two phototrophic organisms [ 14 ].…”

Phytosterol Profiling of Apiaceae Family Seeds Spices Using GC-MS

“…In the present study, campesterol accounted for 9.9% of total sterol; whereas, Hosseini [30] recorded 49.19% campesterol in cumin seeds oil. Heredity (cultivar/variety) [31,32], geographical conditions [33], and several other different biotic and abiotic factors [34] during cultivation and storage [35] are probably responsible for a significant variation in sterol contents and compositions among plants. Thus, the factors influencing sterols contents positively can be identified and utilized for enhancing the sterols contents in the food crops and diet.…”

Phytosterols in human health: friends or foes?

“…In addition to normal physiology, infection of plants can modify their sterol contents. Thus, the infection of tomato (Solanum lycopersicum) with the root-knot nematode Meloidogyne incognita changes the β-sitosterol-to-stigmasterol ratio significantly (Cabianca et al, 2021).…”