Morphological and molecular identification of four Purpureocillium isolates and evaluating their efficacy against the sweet potato whitefly, Bemisia tabaci (Genn.) (Hemiptera: Aleyrodidae)

Tingfei Sun,Shaukat Ali,Jianhui Wu

doi:10.1186/s41938-021-00372-y

Tingfei Sun, Shaukat Ali + Show 1 more

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https://doi.org/10.1186/s41938-021-00372-y

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Abstract

BackgroundEntomopathogenic fungi are widely distributed and well described within the fungal kingdom. This study reports the isolation, characterization, and virulence of 4 Purpureocillium lilacinum isolates against the sweet potato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae).ResultsFour strains of Purpureocillium lilacinum (XI-1, XI-4, XI-5, and J27) were isolated from soil samples from different localities of China. The morphological studies observed that four strains showed essentially the same morphological characteristics. After 7 days of cultivation, the colonies were purple, round, and bulged. Conidia were single-celled, oval to spindle-shaped, chain-like, and the spore size was about 2.0–2.3 × 3.1–4.0 μm. The genome-based identification results showed that ITS sequences of XI-1 (GenBank accession # MW386433), XI-4 (GenBank accession # MW386434), XI-5 (GenBank accession # MW386435), and J27 (GenBank accession # MW386436) were similar to another P. lilacinum. The newly identified strains of P. lilacinum proved pathogenicity to B. tabaci under laboratory conditions. In addition, the P. lilacinum isolate XI-5 was the most virulent one against different nymphal instars of whitefly having median lethal concentration (LC50) values of 4.99 × 106, 4.82 × 105, and 2.85 × 106 conidia/ml, respectively, 7 days post application.ConclusionThe newly isolated strains of P. lilacinum can be developed as a potential biopesticide against the whitefly although extensive field bioassays as well as development of proper formulation are still required.

Highlights

Entomopathogenic fungi are widely distributed and well described within the fungal kingdom
Management of heavy whitefly infestations is still mainly dependent upon broad spectrum conventional insecticides, which have led to the development of insecticide resistance by B. tabaci (Liang et al 2012)
The techniques employed for isolation and identification of entomopathogenic fungi (EPF) have evolved from morphological characterization to amplification of different DNA or RNA fragments through polymerase chain reactions improving the basic understanding about EPF (Canfora et al 2016)

Summary

Introduction

Entomopathogenic fungi are widely distributed and well described within the fungal kingdom. This study reports the isolation, characterization, and virulence of 4 Purpureocillium lilacinum isolates against the sweet potato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae). Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae), is a key pest of different crops and vegetables worldwide along with serving as a vector of many plant viruses (Naranjo et al 2010 and Stansly and Naranjo, 2010). The techniques employed for isolation and identification of EPF have evolved from morphological characterization to amplification of different DNA or RNA fragments through polymerase chain reactions improving the basic understanding about EPF (Canfora et al 2016). Molecular techniques have become widely used for identification of EPF as the genotypic identification methods (such as random amplified polymorphic DNA-polymerase chain reaction) are more precise than the morphological character-based identification (Du et al 2019)

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