Antioxidant Protection by Astaxanthin in the Citrus Red Mite (Acari: Tetranychidae)

Abstract

Solar ultraviolet-B (UVB) radiation and radiant heat have lethal effects on plant-dwelling mites, including spider mites, and their natural enemies, such as phytoseiid mites, leading them to reside on lower leaf surfaces. Panonychus spider mites are outcompeted by Tetranychus spider mites and thus exploit upper leaf surfaces, where they are exposed to both UVB radiation and radiant heat. Panonychus spider mites are thought to produce astaxanthin constitutionally. In this study, we compared carotenoid components, antioxidant capacity, lipid peroxidation, survival, and egg production in wild-type (WTS) and albino-type strains (ATS) of Panonychus citri (McGregor). Four carotenoids (neoxanthin, violaxanthin, lutein, and carotene) and their isomers and esters were identified in both strains, but astaxanthin and its esters were present only in WTS. The singlet oxygen scavenging capacity of lipid-soluble ingredients was greater in WTS than in ATS, whereas the oxygen radical absorbance capacities of hydrophilic ingredients were equivalent between them. Lipid peroxide accumulation was clearly higher in ATS than in WTS under both UVB irradiation (25 °C) and high temperature (35 °C) conditions. The findings are consistent with an antioxidant protective function of astaxanthin in this mite. Survival periods at 38 °C were longer in WTS than in ATS, although no difference was shown at 35 °C or under UVB irradiation. Therefore, astaxanthin accumulation was shown to be a major mechanism for survival under radiant heat, although other mechanisms, such as photoreactivation, might play a major role in survival under UVB radiation.

A Pollen Diet Confers Ultraviolet-B Resistance in Phytoseiid Mites by Providing Antioxidants

“…In a previous study, egg hatchability and survival rate of hatched larvae after UVB radiation were higher for N. californicus females fed P. citri than for females fed T. urticae (Nakai et al, 2018). P. citri possess the strongest antioxidant among carotenoids, astaxanthin (Metcalf and Newell, 1962;Atarashi et al, 2017). Therefore, it is likely that female phytoseiid mites normally (or selectively) deliver antioxidants from food components to their eggs.…”

“…Phytophagous spider mites and predacious phytoseiid mites suffer deleterious effects from solar ultraviolet-B (UVB, 280-315 nm wavelength) radiation (Ohtsuka and Osakabe, 2009;Onzo et al, 2010;Sakai and Osakabe, 2010;Sakai et al, 2012;Osakabe, 2012, 2014;Koveos et al, 2017). UVB radiation generates DNA lesions such as cyclobutane pyrimidine dimers (CPD) and (6-4) photoproducts (6-4PP; Wang et al, 1974;Sinha and Häder, 2002;Murata and Osakabe, 2017), as well as reactive oxygen species (ROS), such as singlet oxygen, which cause oxidative damage to DNA (Kielbassa et al, 1997;Zhang et al, 1997;Cadet et al, 2015) and lipid peroxidation (Girotti, 1998;Miyamoto et al, 2014;Morita et al, 2016;Atarashi et al, 2017). Therefore, many mites avoid UV damage by residing on the lower side of leaves (Sudo and Osakabe, 2011).…”

“…Spider mite species of the Genus Panonychus such as the citrus red mite Panonychus citri (McGregor), constitutively produce astaxanthin, which accumulates mainly as esters (Metcalf and Newell, 1962;Atarashi et al, 2017;Bryon et al, 2017). Astaxanthin is the most powerful antioxidant of the carotenoids (Miki, 1991;Camera et al, 2009;Hama et al, 2012).…”

“…Astaxanthin is the most powerful antioxidant of the carotenoids (Miki, 1991;Camera et al, 2009;Hama et al, 2012). It reduces lipid peroxidation via its antioxidant effects (Atarashi et al, 2017), and thus the eggs of P. citri are more tolerant to UVB radiation than the eggs of the two-spotted spider mite Tetranychus urticae Koch (Fukaya et al, 2013). Moreover, wildtype P. citri females exhibit higher survival rates than albino P. citri females, which lack the capacity to produce astaxanthin, under thermal oxidative stress (Atarashi et al, 2017;Bryon et al, 2017), which suggests that intrinsic astaxanthin confers tolerance to UV radiation.…”

“…It reduces lipid peroxidation via its antioxidant effects (Atarashi et al, 2017), and thus the eggs of P. citri are more tolerant to UVB radiation than the eggs of the two-spotted spider mite Tetranychus urticae Koch (Fukaya et al, 2013). Moreover, wildtype P. citri females exhibit higher survival rates than albino P. citri females, which lack the capacity to produce astaxanthin, under thermal oxidative stress (Atarashi et al, 2017;Bryon et al, 2017), which suggests that intrinsic astaxanthin confers tolerance to UV radiation. Consequently, Panonychus species can use upper leaf surfaces (Foott, 1963;Jones and Parrella, 1984;Morimoto et al, 2006;Osakabe et al, 2006;Fukaya et al, 2013).…”