Astakines are hematopoietic cytokines originally isolated from crustaceans. We identified three astakine-like transcripts in the tarnished plant bug (Lygus lineolaris), LlAst-1, LlAst-2 and LlAst-3, containing prokineticin domains. Quantitative real-time PCR showed variation in expression patterns of astakines in different tissues and between sexes. Relative expression levels of LlAst-1 were highest in the fat bodies of females, while LlAst-2 expression was highest in the fat bodies of both males and females. LlAst-3 expression was higher in male legs compared with the female legs, but lower in all other tissues. Infection with the entomopathogenic fungus Beauveria bassiana slightly elevated LlAst-1 expression 48 h after infection in both males and females. In contrast, the expression levels of LlAst-2 and LlAst-3 were not significantly changed in males and females. Compared with 12:00 h, LlAst-1 level was higher in both sexes at 18:00 h and 00:00 h (midnight). By 6:00 h, the LlAst-1 level in females was significantly reduced while that in males remained high. LlAst-2 and -3 had highest relative expression levels in females at midnight but were significantly lower than in males at midnight and in both sexes at 18:00 h and 6:00 h. This is the first report of expression of astakine-like cytokines from insects.
Keywords: Lygus lineolaris; circadian; hematopoiesis; photoperiod; real-time PCR.
Published 2015. This article is a U.S. Government work and is in the public domain in the USA.