Comparative transcriptomic analysis of Tibetan Gynaephora to explore the genetic basis of insect adaptation to divergent altitude environments

Abstract

Adaptation of insects to different altitudes remain largely unknown, especially those endemic to the Tibetan Plateau (TP). Here, we generated the transcriptomes of Gynaephora menyuanensis and G. alpherakii, inhabiting different high altitudes on the TP, and used these and the previously available transcriptomic and genomic sequences from low-altitude insects to explore potential genetic basis for divergent high-altitude adaptation in Gynaephora. An analysis of 5,869 orthologous genes among Gynaephora and other three low-altitude insects uncovered that fast-evolving genes and positively selected genes (PSGs) in the two Gynaephora species were enriched in energy metabolism and hypoxia response categories (e.g. mitochondrion, oxidation-reduction process, and response to oxidative stress). Particularly, mTOR signaling pathway involving hypoxia was enriched by PSGs, indicating this well-known pathway in mammal hypoxia adaptation may be an important signaling system in Gynaephora. Furthermore, some PSGs were associated with response to hypoxia (e.g. cytochrome proteins), cold (e.g. dehydrogenase) and DNA repair (e.g. DNA repair proteins). Interestingly, several insect-specific genes that were associated with exoskeleton and cuticle development (e.g. chitinase and ecdysteroids) had experienced positive selection, suggesting the specific adaptive mechanisms in insects. This study is favourable for understanding the adaptive evolution of Gynaephora and even TP insects to divergent altitudes.

Transcriptomic signatures of cold adaptation and heat stress in the winter ant (Prenolepis imparis)

“…They are necessary for a wide range of physiological functions such as immunity, digestion, and phagosytosis [ 105 – 107 ]. Chitinase related genes have been induced during cold stress in beetles [ 108 ], and there is evidence of positive selection in chitinase genes in high-altitude Lepidoptera in the genus Gynaephora [ 109 ]. Together with these studies, the increased expression that we detected in Chitinase 3-like indicate that chitinase enzymes are likely important during cold thermal stress.…”

Comparative analysis of the microRNA transcriptomes between two <italic>Gynaephora</italic> species (Lepidoptera: Lymantriinae) inhabiting different high altitudes of the Tibetan Plateau

“…最近, 研究者鉴定到了一批低氧诱导相 关的miRNAs, 它们广泛参与细胞凋亡 [62] 、DNA修 复 [63,64] 、细胞循环 [65] 、血管生成 [66] 和代谢调控 [67] . 因 此, miRNAs极有可能介导草原毛虫对不同海拔环境 [73] 进行(E-value=10 −5 ), 而KEGG富集分析通过KO-BAS 2.0 [74] [18,22] . 已有研究表明, miRNAs对动物生态可塑性的 形成具有重要作用 [22,79~82] , 但是这些研究大多聚焦于 脊椎动物, 而对无脊椎动物、特别是昆虫miRNAs的…”

“…毛虫中下调表达, 且在下调miRNAs中所对应的靶基 因最多. 根据两种草原毛虫mRNA转录组数据(表5) [18] , 目标基因也富集得到了相同的GO条目 [15,18,85] . 值得注 意的是, 靶基因T1_Unigene_ BMK.21587和T2_Unige-ne_BMK.21675的GO功能均与泛素-蛋白连接酶相关.…”

“…、两 栖类 [12] 、哺乳动物 [13,14] 、鱼类 [15] 和人类 [16,17] [23,24] . 最近, 作者从生理、线 粒体基因组和转录组等方面研究了草原毛虫高海拔适 应性进化, 且发现基因的序列变异及表达水平与草原 毛虫对不同海拔环境的适应性进化密切相关 [18,19,22] .…”

Analysis of the Gynaephora qinghaiensis pupae immune transcriptome in response to parasitization by Thektogaster sp

“…Gynaephora qinghaiensis (Lepidoptera: Lymantriidae), a serious economic pest in alpine meadows, is widely dispersed on the Qinghai‐Tibetan Plateau (QTP; Liu, Yan, Mei, & Huo, ), where it not only damages grassland vegetation, making herbivore fodder scarce but also causes canker sores in domestic animals and wildlife (Yan, Wang, & Liu, ; Q. L. Zhang & Yuan, ; Q. L. Zhang, Zhang, Zhao, et al, ; Q. L. Zhang, Zhang, Yang et al, ). Spraying chemical pesticides is the main method of Gynaephora control.…”