title: The expression patterns of the clock genes period and timeless are affected by photoperiod in the Mediterranean corn stalk borer, Sesamia nonagrioides.
abstract: To obtain clues to the link between the molecular mechanism of circadian and photoperiod clocks, we cloned two circadian clock genes, period (per) and timeless (tim) from the moth Sesamia nonagrioides, which undergoes facultative diapause controlled by photoperiod. Sequence analysis revealed a high degree of conservation among the compared insects fοr both genes. We also investigated the expression patterns of per and tim in brains of larvae growing under 16L:8D (long days), constant darkness (DD) and 10L:14D (short days) conditions by qPCR assays. The results showed that mRNA accumulations encoding both genes exhibited diel oscillations under different photoperiods. The oscillation of per and tim mRNA, under short-day photoperiod differed from long-day. The difference between long-day and short-day conditions in the pattern of mRNA levels of per and tim appears to distinguish photoperiodic conditions clearly and both genes were influenced by photoperiod in different ways. We infer that not all photoperiodic clocks of insects interact with circadian clocks in the same fashion. Our results suggest that transcriptional regulations of the both clock genes act in the diapause programing in S. nonagrioides. The expression patterns of these genes are affected by photoperiod but runs with 24 h by entrainment to daily environmental cues.
authors.affiliation: Department of Biotechnology, School of Food, Biotechnology and Development, Agricultural University of Athens, Athens, Greece.
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Kontogiannatos
authors.affiliation: Department of Biotechnology, School of Food, Biotechnology and Development, Agricultural University of Athens, Athens, Greece.
authors.forename: Theodoros
authors.initials: T
authors.lastname: Gkouvitsas
authors.affiliation: Department of Biotechnology, School of Food, Biotechnology and Development, Agricultural University of Athens, Athens, Greece.
authors.forename: Anna
authors.initials: A
authors.lastname: Kourti
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002940:Circadian Rhythm / Q000235:genetics*; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation; D019476:Insect Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D007814:Larva / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D009036:Moths / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D056950:Period Circadian Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D017440:Photoperiod; D010802:Phylogeny; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D018076:DNA, Complementary; D019476:Insect Proteins; D056950:Period Circadian Proteins; D012333:RNA, Messenger
keywords: Sesamia nonagrioides; circadian clock; diapause; period; photoperiodism; timeless