Effects of Lecanicillium lecanii strain JMC-01 on the physiology, biochemistry, and mortality of Bemisia tabaci Q-biotype nymphs

Abstract

Background. Lecanicillium lecanii is an entomopathogenic fungi, which was isolated from insect suffer from a disaster. Now, it is an effective bio-control resource that can control agricultural pests such as whitefly and aphids. There are many studies on the control of various agricultural pests by L. lecanii, but no report on its control of Bemisia tabaci biotype-Q exists. In this work we studied the susceptibility of B. tabaci Q-biotype (from Ningxia, China) to L. lecanii JMC-01 in terms of nymph mortality and the changes in detoxifying protective enzymes activities. Methods. Bemisia tabaci nymphs were exposed to L. lecanii JMC-01 conidia by immersion with the host culture. Mortality was assessed daily for all nymph stages. The detoxifying and protective enzyme activity changes, weight changes, and fat, and water contents of the nymphs were determined spectrophotometrically. Results. All instars of B. tabaci died after being infested with 1×108 conidia/mL. The 2nd-instar nymphs were the most susceptible, followed by the 3rd-instar nymphs. The corrected cumulative mortality of the 2nd- and 3rd-instar nymphs was 82.22% and 75.55%, respectively. The levels of detoxifying and protective enzymes initially increased and then decreased. The highest activities of carboxylesterase (CarE), acetylcholinesterase (AchE), peroxidase (POD), and catalase (CAT) occurred on the 3rd day, reaching 10.5 U/mg prot, 0.32 U/mg prot, 20 U/mg prot, and 6.3 U/mg prot, respectively. These levels were 2.2-fold, 4.3-fold, 2.4-fold, and 1.4-fold the control levels, respectively. The highest activities of glutathione-S transferase (GSTs) and superoxide dismutase (SOD) on the 2nd day were, respectively, 64 U/mg prot and 43.5 U/mg prot. These levels were, respectively, 2.7-fold and 1.1-fold that of the control level. The water and fat content in the infected B. tabaci nymphs decreased and differed significantly from the control levels. The weight increased continuously in the first 24 h, decreasing thereafter. At 72 h, the infestation level was about 0.78-fold that of the control level. Conclusions. The studied L. lecanii JMC-01 strain is pathogenic to the B. tabaci Q-biotype. This strain interferes with the normal functioning of detoxifying and protective enzymes, and is also involved in the disruption of normal physiological metabolism in B. tabaci.

Infection of Metarhizium anisopliae Ma6 and defense responses of host Phyllotreta striolata adults

“…The maximum activities of POD were detected on the 1st day. Previous studies indicated that after infection of entomogenous fungus, the activities of SOD, CAT, and POD of hosts initially increased but then decreased (Xie et al, 2019; Ye et al, 2018). At the early stage, to resist the infection of fungi for maintaining normal physiological activities, the enzymes activities of SOD, CAT, and POD increased.…”

In vitro virulence of three Lecanicillium lecanii strains against the whitefly, Bemisia tabaci (Genn.) (Hemiptera: Aleyrodidae)

“…During this process, the fungus produces several infection specific structures, including penetration pegs or appressoria, enabling the developing hyphae to enter the host integument (Ortiz-Urquiza and Keyhani 2013). L. lecanii has been documented to infect B. tabaci (Zhu and Kim 2011) causing a good mortality (Xie et al 2019).…”

Efficacy of an Omani strain ofCordyceps javanicaand its culture filtrate against whitefly (Bemisia tabaci) under laboratory conditions

“…Biological control method is widely adopted for the control of whitefly in order to avoid environmental pollution and development of resistance in the insect populations that are generally associated with the use of synthetic chemical pesticides (Faria and Wraight 2001;Sani et al 2020). Several entomopathogenic fungi, including Beauveria bassiana (Xia et al 2013), Verticillium lecanii (Xie et al 2019), Metarhizium anisopliae (Norhelina et al 2013), Isaria fumosorosea (Paecilomyces fumosoroseus) (Mascarin et al 2013), Lecanicillium muscarium (Ali et al 2017) and Cordyceps javanica (Xie et al 2016), have been reported to be efficacious against B. tabaci. The toxic metabolites produced by V. lecanii (Gindin et al 1994;Wang et al 2007) and Metarhizium anisopliae (Zhang et al 2017) have been reported to play an important role in the mortality of B. tabaci.…”