Aphid growth and reproduction on plants with altered sterol profiles: Novel insights using Arabidopsis mutant and overexpression lines. (May 2020)

• Record Type: Journal Article
• Authors: Chen, Ivy W.; Grebenok, Robert J.; Schaller, Hubert; Zhu-Salzman, Keyan; Behmer, Spencer T.
• Is Part Of: Journal of insect physiology. Volume 123(2020)
• Publication Date: 2020-05
• Subjects: Arabidopsis -- Myzus persicae -- Phytosterols -- Cholesterol -- Plant-insect interactions; Insects -- Physiology -- Periodicals; Insectes -- Physiologie -- Périodiques; Insects -- Physiology; Periodicals; 571.157
• DOI: 10.1016/j.jinsphys.2020.104054
• Languages: English
• ISSNs: 0022-1910

Abstract

Graphical abstract: Highlights: Aphid performance was studied using Arabidopsis lines with modified sterol profiles. Aphids on plant lines with atypical sterols showed reduced growth and reproduction. Aphid performance was poor on plants with reduced β -sitosterol. Aphid performance on plants with elevated sterol amounts was similar to controls. The sterol profile of aphids does not reflect the sterol profile of their host plants. Abstract: Sterols are essential membrane components and are critical for many physiological processes in all eukaryotes. Insects and other arthropods are sterol auxotrophs that typically rely on a dietary source of sterols. Herbivorous insects generally obtain sterols from plants and then metabolize them into cholesterol, the dominant sterol in most insects. However, there is significant variation in phytosterol structure, and not all phytosterols are equally suitable for insects. In the current study, we used seven Arabidopsis thaliana lines that display altered sterol profiles due to mutations in the sterol biosynthetic pathway or to overexpression of key enzymes of the pathway, and investigated how plant sterol profiles affected green peach aphid ( Myzus persicae ) growth and reproduction. We also characterized the sterol profile of aphids reared on these Arabidopsis genotypes. Aphids on two mutant lines ( 14R/fk and ste1-1 ) that accumulated biosynthetic sterol intermediates (Δ 8, 14 -sterols, and Δ 7 -sterols, respectively) all showed significantly reduced growth and reproduction. Aphids on SMT2 COSUP plants (which have decreased β -sitosterol but increased campesterol) also displayed significantly reduced growth and reproduction. However, aphids on SMT2 OE plants (which have increased β -sitosterol but decreased campesterol) performed similarly to aphids on wild-type plants. Finally, Arabidopsis plants that had an overproduction of sterols ( CD-HMGR OE ) or decreased sterol esters ( psat1-2 ) had no impact on aphid performance. Two noteworthy results come from the aphid sterol profile study. First, β -sitosterol, cholesterol and stigmasterol were recovered in all aphids. Second, we did not detect Δ 8, 14 -sterols in aphids reared on 14R/fk plants. We discuss the implications of our findings, including how aphid sterol content does not appear to reflect plant leaf sterol profiles. We also discuss the potential of modifying plant sterol profiles to control insect herbivore pests, including aphids.