Expression profiles of tyrosine metabolic pathway genes and functional analysis of DOPA decarboxylase in puparium tanning of Bactrocera dorsalis (Hendel)

Abstract

BACKGROUND Tanning is an important physiological process with critical roles in cuticle pigmentation and sclerotization. Previous studies have shown that insect cuticle tanning is closely associated with the tyrosine metabolism pathway, which consists of a series of enzymes. RESULTS In this study, 24 tyrosine metabolism pathway genes were identified in the oriental fruit fly Bactrocera dorsalis (Hendel) genome. Gene expression profiles throughout 15 developmental stages of B. dorsalis were established based on our previous RNA sequencing data, and we found that 13 enzyme genes could be involved in the process of pupariation. Accordingly, a tyrosine‐mediated tanning pathway during the pupariation of B. dorsalis was predicted and a critical enzyme, 3,4‐dihydroxyphenylalanine (DOPA) decarboxylase (DDC), was used to explore its possible roles in formation of the puparium. First, a real‐time quantitative polymerase chain reaction confirmed that BdDDC had an epidermis‐specific expression pattern, and was highly expressed during larval metamorphosis in B. dorsalis. Subsequent disruption of BdDDC by feeding 5‐day‐old larvae with DDC inhibitor (l‐α‐methyl‐DOPA) could lead to: (i) a significant decrease in BdDDC enzyme activity and dopamine concentration; (ii) defects in puparium pigmentation; (iii) impairment of the morphology and less thickness of the puparium; and (iv) lower pupal weight and obstacles to eclosion. CONCLUSION This study provided a potential tyrosine metabolic pathway that was responsible for insect tanning during pupariation, and the BdDDC enzyme has been shown to have crucial roles in larval–pupal tanning of B. dorsalis. © 2021 Society of Chemical Industry.

MicroRNAs miR‐14 and miR‐2766 regulate tyrosine hydroxylase to control larval–pupal metamorphosis in Helicoverpa armigera

“…TH and DDC are critical components of DA biosynthesis, which was indispensable for the tyrosine metabolism pathway 39, 50 . In Bactrocera dorsalis , BdTH and BdDDC were highly expressed during larval–pupal transition, suggesting their important roles in puparium tanning, 47 which is consistent with our results. Therefore, we can infer that DA regulation of cuticle tanning may be another way to control larval metamorphosis.…”

“…These results indicated that DA might modulate larval–pupal metamorphosis in H. armigera . Previous studies have proved that TH and DDC are required for cuticle tanning, 46, 47 but expression levels of TH and DDC were not found to be high in the EP. We speculated that this may be related to the detection period, because larvae have completed cuticle tanning of the EP in the new instar on day 2 of the fifth instar.…”

Transcriptome Analysis to Identify Responsive Genes under Sublethal Concentration of Bifenazate in the Diamondback Moth, Plutella xylostella (Linnaeus, 1758) (Lepidoptera: Plutellidae)

“…Moreover, tyrosine metabolism played an important role in the maintenance of normal insect development, and it has been confirmed that this pathway was essential for insect cuticle tanning (pigmentation and sclerotization) reproduction, survival, molting, immunity, and protecting the insect from an exogenous physical injury in different insect species [ 59 , 60 , 61 ]. As expected, previous studies have suggested that the repression of tyrosine metabolism by knocking down specific genes through RNA interference could significantly block the cuticle tanning and larval pupation process, impair melanization immune responses and eventually lead to high insect mortality [ 58 , 59 , 60 , 61 , 62 , 63 ]. Purines are abundant metabolic substrates that participate in different kinds of cellular processes, and they serve as the biosynthesis of DNA and RNA to confirm cell survival and proliferation [ 64 ].…”

“…In contrast to the over-expressed genes that followed bifenazate treatment in P. xylostella , this paper also showed six and nine down-regulated genes were significantly enriched in tyrosine metabolism and purine metabolism pathways, respectively. It has demonstrated that tyrosine metabolism is a complicated physiological process, which consists of a series of enzyme reactions that starts with tyrosine [ 58 ]. Moreover, tyrosine metabolism played an important role in the maintenance of normal insect development, and it has been confirmed that this pathway was essential for insect cuticle tanning (pigmentation and sclerotization) reproduction, survival, molting, immunity, and protecting the insect from an exogenous physical injury in different insect species [ 59 , 60 , 61 ].…”

Pupal Age Estimation of Sarcophaga peregrina (Diptera: Sarcophagidae) at Different Constant Temperatures Utilizing ATR-FTIR Spectroscopy and Cuticular Hydrocarbons

“…Insect mobility, mechanical support, body form, and normal growth are all maintained by the cuticle, which is the outermost layer of the insect body [ 46 ]. The cuticle periodically degrades and rebuilds and is important for growth during the molting and metamorphosis of insects [ 47 ].…”