title: Gut symbiotic bacteria stimulate insect growth and egg production by modulating hexamerin and vitellogenin gene expression.
abstract: Recent studies have suggested that gut symbionts modulate insect development and reproduction. However, the mechanisms by which gut symbionts modulate host physiologies and the molecules involved in these changes are unclear. To address these questions, we prepared three different groups of the insect Riptortus pedestris: Burkholderia gut symbiont-colonized (Sym) insects, Burkholderia-non-colonized (Apo) insects, and Burkholderia-depleted (SymBurk-) insects, which were fed tetracycline. When the hemolymph proteins of three insects were analyzed by SDS-PAGE, the hexamerin-α, hexamerin-β and vitellogenin-1 proteins of Sym-adults were highly expressed compared to those of Apo- and SymBurk--insects. To investigate the expression patterns of these three genes during insect development, we measured the transcriptional levels of these genes. The hexamerin-β gene was specifically expressed at all nymphal stages, and its expression was detected 4-5 days earlier in Sym-insect nymphs than that in Apo- and SymBurk--insects. However, the hexamerin-α and vitellogenin-1 genes were only expressed in adult females, and they were also detected 6-7 days earlier and were 2-fold higher in Sym-adult females than those in the other insects. Depletion of hexamerin-β by RNA interference in 2nd instar Sym-nymphs delayed adult emergence, whereas hexamerin-α and vitellogenin-1 RNA interference in 5th instar nymphs caused loss of color of the eggs of Sym-insects. These results demonstrate that the Burkholderia gut symbiont modulates host development and egg production by regulating production of these three hemolymph storage proteins.
authors.affiliation: Global Research Laboratory of Insect Symbiosis, College of Pharmacy, Pusan National University, Busan 46241, South Korea.
authors.forename: Jun Beom
authors.initials: JB
authors.lastname: Lee
authors.affiliation: Global Research Laboratory of Insect Symbiosis, College of Pharmacy, Pusan National University, Busan 46241, South Korea.
authors.forename: Kyoung-Eun
authors.initials: KE
authors.lastname: Park
authors.affiliation: Global Research Laboratory of Insect Symbiosis, College of Pharmacy, Pusan National University, Busan 46241, South Korea.
authors.forename: Seung Ah
authors.initials: SA
authors.lastname: Lee
authors.affiliation: Global Research Laboratory of Insect Symbiosis, College of Pharmacy, Pusan National University, Busan 46241, South Korea.
authors.forename: Seong Han
authors.initials: SH
authors.lastname: Jang
authors.affiliation: Global Research Laboratory of Insect Symbiosis, College of Pharmacy, Pusan National University, Busan 46241, South Korea.
authors.forename: Ho Jeong
authors.initials: HJ
authors.lastname: Eo
authors.affiliation: Global Research Laboratory of Insect Symbiosis, College of Pharmacy, Pusan National University, Busan 46241, South Korea.
authors.forename: Ho Am
authors.initials: HA
authors.lastname: Jang
authors.affiliation: Global Research Laboratory of Insect Symbiosis, College of Pharmacy, Pusan National University, Busan 46241, South Korea.
authors.forename: Chan-Hee
authors.initials: CH
authors.lastname: Kim
authors.affiliation: Graduate School of Agriculture, Hokkaido University, Sapporo 060-8589, Japan.
authors.forename: Tsubasa
authors.initials: T
authors.lastname: Ohbayashi
authors.affiliation: Tropical Biosphere Research Center, University of the Ryukyus, Nishihara 903-0213, Japan.
authors.forename: Yu
authors.initials: Y
authors.lastname: Matsuura
authors.affiliation: Graduate School of Agriculture, Hokkaido University, Sapporo 060-8589, Japan; National Institute of Advanced Industrial Science and Technology (AIST), Hokkaido Center, Sapporo 062-8517, Japan.
authors.forename: Yoshitomo
authors.initials: Y
authors.lastname: Kikuchi
authors.affiliation: National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 305-8566, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Futahashi
authors.affiliation: National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 305-8566, Japan.
authors.forename: Takema
authors.initials: T
authors.lastname: Fukatsu
authors.affiliation: Global Research Laboratory of Insect Symbiosis, College of Pharmacy, Pusan National University, Busan 46241, South Korea. Electronic address: brlee@pusan.ac.kr.
authors.forename: Bok Luel
authors.initials: BL
authors.lastname: Lee
mesh_terms: D000818:Animals; D019117:Burkholderia / Q000502:physiology*; D004531:Eggs; D005298:Fertility; D000069196:Gastrointestinal Microbiome / Q000276:immunology*; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D006458:Hemolymph / Q000378:metabolism; D020062:Heteroptera / Q000502:physiology*; D019476:Insect Proteins / Q000235:genetics / Q000378:metabolism*; D008018:Life Cycle Stages; D034741:RNA, Small Interfering / Q000235:genetics; D012098:Reproduction; D013559:Symbiosis; D013752:Tetracycline / Q000008:administration & dosage; D014819:Vitellogenins / Q000235:genetics / Q000378:metabolism*
chemical_list: D019476:Insect Proteins; D034741:RNA, Small Interfering; D014819:Vitellogenins; C041137:storage proteins, Insecta; D013752:Tetracycline
keywords: Burkholderia; Hexamerin; Riptortus pedestris; Symbiosis; Symbiosis-affected host molecule; Vitellogenin