Molecular characterization of prophenoloxidase-1 (PPO1) and the inhibitory effect of kojic acid on phenoloxidase (PO) activity and on the development of Zeugodacus tau (Walker) (Diptera: Tephritidae). Issue 2 (22nd June 2018)

• Record Type: Journal Article
• Authors: Zhang, H.-H.; Luo, M.-J.; Zhang, Q.-W.; Cai, P.-M.; Idrees, A.; Ji, Q.-E.; Yang, J.-Q.; Chen, J.-H.
• Is Part Of: Bulletin of entomological research. Volume 109:Issue 2(2019)
• Page Start: 236
• Page End: 247
• Publication Date: 2018-06-22
• Subjects: development, -- inhibitor, -- kojic acid, -- phenoloxidase activity, -- transcriptional levels; Entomology -- Periodicals; 595.7
• DOI: 10.1017/S0007485318000470
• Languages: English
• ISSNs: 0007-4853

Abstract

Abstract: Phenoloxidase (PO) plays a key role in melanin biosynthesis during insect development. Here, we isolated the 2310-bp full-length cDNA of PPO1 from Zeugodacus tau, a destructive horticultural pest. qRT-polymerase chain reaction showed that the ZtPPO1 transcripts were highly expressed during larval–prepupal transition and in the haemolymph. When the larvae were fed a 1.66% kojic acid (KA)-containing diet, the levels of the ZtPPO1 transcripts significantly increased by 2.79- and 3.39-fold in the whole larvae and cuticles, respectively, while the corresponding PO activity was significantly reduced; in addition, the larval and pupal durations were significantly prolonged; pupal weights were lowered; and abnormal phenotypes were observed. An in vitro inhibition experiment indicated that KA was an effective competitive inhibitor of PO in Z. tau . Additionally, the functional analysis showed that 20E could significantly up-regulate the expression of ZtPPO1, induce lower pupal weight, and advance pupation. Knockdown of the ZtPPO1 gene by RNAi significantly decreased mRNA levels after 24 h and led to low pupation rates and incomplete pupae with abnormal phenotypes during the larval-pupal interim period. These results proved that PO is important for the normal growth of Z. tau and that KA can disrupt the development of this pest insect.