Selenium-tolerant diamondback moth disarms hyperaccumulator plantdefense

Journal Article · Mon Nov 20 04:00:00 EST 2006 · Current Biology

DOI:https://doi.org/10.1016/j.cub.2006.09.015· OSTI ID:919389

Freeman, J L; Quinn, C F; Marcus, M A; Fakra, S; Pilon-Smits, E A.H.

Background Some plants hyperaccumulate the toxic element selenium (Se) to extreme levels, up to 1% of dry weight. The function of this intriguing phenomenon is obscure. Results Here, we show that the Se in the hyperaccumulator prince's plume (Stanleya pinnata) protects it from caterpillar herbivory because of deterrence and toxicity. In its natural habitat, however, a newly discovered variety of the invasive diamondback moth (Plutella xylostella) has disarmed this elemental defense. It thrives on plants containing highly toxic Se levels and shows no oviposition or feeding deterrence, in contrast to related varieties. Interestingly, a Se-tolerant wasp (Diadegma insulare) was found to parasitize the tolerant moth. The insect's Se tolerance mechanism was revealed by X-ray absorption spectroscopy and liquid chromatography--mass spectroscopy, which showed that the Se-tolerant moth and its parasite both accumulate methylselenocysteine, the same form found in the hyperaccumulator plant, whereas related sensitive moths accumulate selenocysteine. The latter is toxic because of its nonspecific incorporation into proteins. Indeed, the Se-tolerant diamondback moth incorporated less Se into protein. Additionally, the tolerant variety sequestered Se in distinct abdominal areas, potentially involved in detoxification and larval defense to predators. Conclusions Although Se hyperaccumulation protects plants from herbivory by some invertebrates, it can give rise to the evolution of unique Se-tolerant herbivores and thus provide a portal for Se into the local ecosystem. In a broader context, this study provides insight into the possible ecological implications of using Se-enriched crops as a source of anti-carcinogenic selenocompounds and for the remediation of Se-polluted environments.

• Research Organization: COLLABORATION - Colorado StateU.
• DOE Contract Number: AC02-05CH11231
• OSTI ID: 919389
• Report Number(s): LBNL--62772
• Journal Information: Current Biology, Journal Name: Current Biology Vol. 16
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
ABSORPTION SPECTROSCOPY
CROPS
DETOXIFICATION
FEEDING
HABITAT
INVERTEBRATES
MOTHS
PARASITES
PLUMES
PROTEINS
SELENIUM
SPECTROSCOPY
TOLERANCE
TOXICITY
WASPS
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