Molecular characterization and expression of six heat shock protein genes in relation to development and temperature in Trichogramma chilonis

PLOS ONE, Sep 2018

Trichogramma is a kind of egg parasitoid wasp that is widely used to control lepidopterous pests. Temperature is one of the main factors that determines the various life activities of this species, including development, reproduction and parasitism efficiency. Heat shock proteins (HSPs) are highly conserved and ubiquitous proteins that are best known for their responsiveness to temperature and other stresses. To explore the potential role of HSPs in Trichogramma species, we obtained the full-length cDNAs of six HSP genes (Tchsp10, Tchsp21.6, Tchsp60, Tchsp70, Tchsc70-3, and Tchsp90) from T. chilonis and analyzed their expression patterns during development and exposure to temperature stress. The deduced amino acid sequences of these HSP genes contained the typical signatures of their corresponding protein family and showed high homology to their counterparts in other species. The expression levels of Tchsp10, Tchsp21.6 and Tchsp60 decreased during development. However, the expression of Tchsc70-3 increased from the pupal stage to the adult stage. Tchsp70 and Tchsp90 exhibited the highest expression levels in the adult stage. The expression of six Tchsps was dramatically upregulated after 1 h of exposure to 32 and 40°C but did not significantly change after 1 h of exposure to 10 and 17°C. This result indicated that heat stress, rather than cold stress, induced the expression of HSP genes. Furthermore, the expression of these genes was time dependent, and the expression of each gene reached its peak after 1 h of heat exposure (40°C). Tchsp10 and Tchsp70 exhibited a low-intensity cold response after 4 and 8 h of exposure to 10°C, respectively, but the other genes did not respond to cold at any time points. These results suggested that HSPs may play different roles in the development of this organism and in its response to temperature stress.

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Molecular characterization and expression of six heat shock protein genes in relation to development and temperature in Trichogramma chilonis

et al. (2018) Molecular characterization and expression of six heat shock protein genes in relation to development and temperature in Trichogramma chilonis. PLoS ONE 13(9): e0203904. https://doi. org/10.1371/journal.pone.0203904 Molecular characterization and expression of six heat shock protein genes in relation to development and temperature in Trichogramma chilonis Jiequn Yi 0 1 Han Wu 0 1 Jianbai Liu 0 1 Xueshuang Lai 0 1 Jixing Guo 0 1 Dunsong Li 1 Guren ZhangID 0 1 0 State Key Laboratory for Biocontrol & Institute of Entomology, Sun Yat-Sen University , Guangzhou, Guangdong , China , 2 Guangdong Provincial Key Laboratory of High Technology for Plant Protection/Plant Protection Research Institute, Guangdong Academy of Agricultural Sciences , Guangzhou, Guangdong , China 1 Editor: Didier Picard, UniversiteA? de Gene?ve , SWITZERLAND - Data Availability Statement: All relevant data are within the paper and its Supporting Information files. Trichogramma is a kind of egg parasitoid wasp that is widely used to control lepidopterous pests. Temperature is one of the main factors that determines the various life activities of this species, including development, reproduction and parasitism efficiency. Heat shock proteins (HSPs) are highly conserved and ubiquitous proteins that are best known for their responsiveness to temperature and other stresses. To explore the potential role of HSPs in Trichogramma species, we obtained the full-length cDNAs of six HSP genes (Tchsp10, Tchsp21.6, Tchsp60, Tchsp70, Tchsc70-3, and Tchsp90) from T. chilonis and analyzed their expression patterns during development and exposure to temperature stress. The deduced amino acid sequences of these HSP genes contained the typical signatures of their corresponding protein family and showed high homology to their counterparts in other species. The expression levels of Tchsp10, Tchsp21.6 and Tchsp60 decreased during development. However, the expression of Tchsc70-3 increased from the pupal stage to the adult stage. Tchsp70 and Tchsp90 exhibited the highest expression levels in the adult stage. The expression of six Tchsps was dramatically upregulated after 1 h of exposure to 32 and 40?C but did not significantly change after 1 h of exposure to 10 and 17?C. This result indicated that heat stress, rather than cold stress, induced the expression of HSP genes. Furthermore, the expression of these genes was time dependent, and the expression of each gene reached its peak after 1 h of heat exposure (40?C). Tchsp10 and Tchsp70 exhibited a low-intensity cold response after 4 and 8 h of exposure to 10?C, respectively, but the other genes did not respond to cold at any time points. These results suggested that HSPs may play different roles in the development of this organism and in its response to temperature stress. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Introduction Wasps of the genus Trichogramma (Hymenoptera: Trichogrammatidae) are tiny egg parasitoids of numerous insect species that are distributed around the world [1?3]. These wasps are easily mass reared and have a broad range of hosts [ 4 ]. Since 1975, several species of Trichogramma have been commonly used as biological control agents for various pests in agricultural and forest systems [ 5, 6 ]. Among these parasitoid wasps, T. chilonis is one of the most successful species in controlling lepidopterous pests, including Chilo spp. (Lepidoptera: Pyralidae), Helicoverpa armigera (Lepidoptera: Noctuidae) and Pectinophora gossypiella (Lepidoptera: Gelechiidae) [2]. In China, T. chilonis is widely distributed and is employed in integrated pest management for rice, cotton, sugarcane and other crops [ 7 ]. Temperature is a vital factor that determines the distribution and abundance of animals [ 8 ]. It is also crucial for the successful introduction of Trichogramma species because it influences their development, survival, reproduction, and sex ratio, as well as their parasitism efficiency [ 3, 9 ]. Previous studies have claimed that Trichogramma species can live under a wide range of temperatures from 9 to 36?C [10]. The temperature range of 25?30?C is considered optimal for rearing T. chilonis in the laboratory [ 11 ]. Temperatures beyond the optimal conditions could cause detrimental effects on various biological aspects of the wasps. For instance, T. chilonis and three other Trichogramma species cannot parasitize the eggs of Cnaphalocrocis medinalis (Guene?e) (Lepidoptera: Pyralidae) at 36?C [ 12 ]. The emergence and host parasitization of T. chilonis are 98.0% and 95.6% at 28?C but decrease to 33.7% and 60.1%, respectively, at 35?C [ 9 ]. Moreover, a low temperature of 15?C leads to long developmental periods for T. chilonis (26.3 days) and Trichogrammatoidea bactrae (25.6 days) (Hymenoptera: Trichogrammatidae) [ 4 ]. Although detrimental consequences caused by temperature stre (...truncated)


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Jiequn Yi, Han Wu, Jianbai Liu, Xueshuang Lai, Jixing Guo, Dunsong Li, Guren Zhang. Molecular characterization and expression of six heat shock protein genes in relation to development and temperature in Trichogramma chilonis, PLOS ONE, 2018, Volume 13, Issue 9, DOI: 10.1371/journal.pone.0203904