Transcriptome analyses of the Chinese white pine beetle-fungal symbiont Leptographium qinlingensis under terpene stress or growth on host pine sawdust

AbstractThe Chinese white pine beetle Dendroctonus armandi (Coleoptera: Scolytinae) typically displays bivoltinism at altitudes below 1700 m in the Qinling Mountains, China. The periods of host colonization and larval overwintering are two important phases in the life cycle of bark beetles, as it is during these periods that they have to contend with host plant defences and periods of intense cold, respectively. Although during different seasons, the females and males of Chinese white pine beetles show varying tolerances to host plant terpenoids, the sex ratio and survival physiology condition of the two beetle generations are unknown. We investigated the sex ratio of individuals, and also examined the body mass, energy stores, and detoxication enzymes of males and females in each of the two generations in order to determine the overall population stability of each generation. We identified a female-biased sex ratio among adults in both generations. Furthermore, patterns of body mass, energy stores, and detoxication enzymes were found to differ between the two sexes and two seasons. Compared with the males, the females have a larger body mass and higher amounts of stored lipids, which are assumed to be adaptations designed to overcome host resistance and facilitate subsequent oviposition.

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Cloning and Expression of the Neuropeptide F and Neuropeptide F Receptor Genes and Their Regulation of Food Intake in the Chinese White Pine Beetle Dendroctonus armandi

Frontiers in Physiology ◽

10.3389/fphys.2021.662651 ◽

2021 ◽

Vol 12 ◽

Author(s):

Bin Liu ◽

Danyang Fu ◽

Haiming Gao ◽

Hang Ning ◽

Yaya Sun ◽

...

Keyword(s):

Food Intake ◽

Developmental Stages ◽

Amino Acid Sequences ◽

Cloning And Expression ◽

White Pine ◽

Positive Role ◽

Chinese White ◽

Pine Beetle ◽

Neuropeptide F ◽

G Protein Coupled

Neuropeptide F (NPF) is an important signaling molecule that acts as a neuromodulator to regulate a diversity of physiological and behavioral processes from vertebrates to invertebrates by interaction with NPF receptors, which are G protein-coupled receptors (GPCR). However, nothing is known about NPF in Chinese white pine beetle, Dendroctonus armandi, a destructive pest of natural and coniferous forests in the middle Qinling Mountains of China. We have cloned and characterized cDNAs encoding one NPF precursor and two NPF receptors in D. armandi and made bioinformatics predictions according to the deduced amino acid sequences. They were highly similar to that of Dendroctonus ponderosa. The transcription levels of these genes were different between larvae and adults of sexes, and there were significant differences among the different developmental stages and tissues and between beetles under starvation and following re-feeding states. Additionally, downregulation of NPF and NPFR by injecting dsRNA into beetles reduced their food intake, caused increases of mortality and decreases of body weight, and also resulted in a decrease of glycogen and free fatty acid and an increase of trehalose. These results indicate that the NPF signaling pathway plays a significant positive role in the regulation of food intake and provides a potential target for the sustainable management of this pest.

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Phylogeny of Leptographium Qinlingensis Cytochrome P450 Genes and Their Expression When Grown on Different Media or Treated With Terpenoids

10.21203/rs.3.rs-567036/v1 ◽

2021 ◽

Author(s):

Lulu Dai ◽

Jie Zheng ◽

Jiaqi Ye ◽

Hui Chen

Keyword(s):

Cytochrome P450 ◽

Sole Carbon Source ◽

Common Ancestor ◽

Expression Profiles ◽

White Pine ◽

Host Trees ◽

Chinese White ◽

Cytochrome P450 Genes ◽

Pine Beetle ◽

Fungal Associate

Abstract Leptographium qinlingensis is a fungal associate of the Chinese white pine beetle (Dendroctonus armandi) and a pathogen of the Chinese white pine (Pinus armandi) that must overcome the terpenoid oleoresin defences of host trees. We identified and phylogenetically analysed the cytochrome P450 (CYP) genes in the transcriptome of L. qinlingensis. Through analyses of the growth rates on different nutritional media and inhibition by terpenoids, the expression profiles of six CYPs in the mycelium of L. qinlingensis grown on different media or treated with terpenoids were determined. The CYP evolution predicted that most of the CYPs occurred in a putative common ancestor shared between L. qinlingensis and G. clavigera. This fungus is symbiotic with D. armandi and has more similarity with G. clavigera, which can retrieve nutrition from pine wood and utilize monoterpenes as the sole carbon source. Some CYP genes might be involved in the metabolism of fatty acids and detoxification of terpenes and phenolics, as observed in other blue-stained fungi, which also indicates the pathogenic properties of L. qinlingensis in Chinese white pine.

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