Characterization of UDP-Glucuronosyltransferases and the Potential Contribution to Nicotine Tolerance in Myzus persicae.

Yiou Pan,Xuemei Liu,Qingli Shang,Xiaochun Zeng,Pengjun Xu

doi:10.3390/ijms20153637

Abstract

Uridine diphosphate (UDP)-glycosyltransferases (UGTs) are major phase II detoxification enzymes involved in glycosylation of lipophilic endobiotics and xenobiotics, including phytoalexins. Nicotine, one of the most abundant secondary plant metabolites in tobacco, is highly toxic to herbivorous insects. Plant-herbivore competition is the major impetus for the evolution of large superfamilies of UGTs and other detoxification enzymes. However, UGT functions in green peach aphid (Myzus persicae) adaptation are unknown. In this study, we show that UGT inhibitors (sulfinpyrazone and 5-nitrouracil) significantly increased nicotine toxicity in M. persicae nicotianae, suggesting that UGTs may be involved in nicotine tolerance. In total, 101 UGT transcripts identified in the M. persicae genome/transcriptome were renamed according to the UGT Nomenclature Committee guidelines and grouped into 11 families, UGT329, UGT330, UGT339, UGT341–UGT345, and UGT348–UGT350, with UGT344 containing the most (57). Ten UGTs (UGT330A3, UGT339A2, UGT341A6, UGT342B3, UGT343C3, UGT344D5, UGT344D8, UGT348A3, UGT349A3, and UGT350A3) were highly expressed in M. persicae nicotianae compared to M. persicae sensu stricto. Knockdown of four UGTs (UGT330A3, UGT344D5, UGT348A3, and UGT349A3) significantly increased M. persicae nicotianae sensitivity to nicotine, suggesting that UGT expression in this subspecies may be associated with nicotine tolerance and thus host adaptation. This study reveals possible UGTs relevant to nicotine adaptation in tobacco-consuming M. persicae nicotianae, and the findings will facilitate further validation of the roles of these UGTs in nicotine tolerance.

Highlights

The peach potato or green peach aphid Myzus persicae Sulzer (Hemiptera: Aphididae) is a globally important pest that affects a broad range of agricultural and horticultural crops, causing significant damage both through direct feeding and transmission of many plant viruses [1]
The results of the synergistic effects of 5-Nul and Sul on nicotine toxicity in M. persicae nicotianae are presented in Figure 1. 5-Nul and Sul possibly increased nicotine toxicity in apterous adult M. persicae nicotianae; mortality increased from 49.07% under nicotine treatment alone (100 mg/L) to 65.86%/66.13% under nicotine treatment (100 mg/L) with 5-Nul/Sul (12.5 mg/L) treatment (Figure 1)
These results indicate that UGTs may be involved in nicotine tolerance in M. persicae nicotianae

Summary

Introduction

The peach potato or green peach aphid Myzus persicae Sulzer (Hemiptera: Aphididae) is a globally important pest that affects a broad range of agricultural and horticultural crops, causing significant damage both through direct feeding and transmission of many plant viruses [1]. The ability of M. persicae to adapt to new host plants has led to the formation of host races. The best documented case of this phenomenon is the adaptation of M. persicae to the host plant tobacco (Nicotiana tabacum L.); this led to the host race designated M. persicae nicotianae [2]. M. persicae nicotianae is morphologically and genetically distinct from M. persicae sensu stricto (s.s.). There are clear examples of gene flow between the two taxa [3]. In another case, M. persicae clones collected from Western Australia have adapted to feed successfully on Lupinus angustifolius (narrow-leafed lupine), and this adaptation might be due to enhanced tolerance to lupanine in the diet compared to that of non-adapted clones [4]

Methods

Results

Conclusion