AUTHOR=Zhou Yeming , Zou Xiao , Zhi Junrui , Xie Jiqin , Jiang Tao 

TITLE=Fast Recognition of Lecanicillium spp., and Its Virulence Against Frankliniella occidentalis

JOURNAL=Frontiers in Microbiology

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2020.561381

DOI=10.3389/fmicb.2020.561381

ISSN=1664-302X

ABSTRACT=<sec><title>Background</title><p><italic>Frankliniella occidentalis</italic> (Thysanoptera: Thripidae) is a highly rasping-sucking pest of numerous crops. The entomogenous fungi of <italic>Lecanicillium</italic> spp. are important pathogens of insect pests, and some species have been developed as commercial biopesticides. To explore <italic>Lecanicillium</italic> spp. resources in the development of more effective <italic>F. occidentalis</italic> controls, efficient barcode combinations for strain identification were screened from internal transcribed spacers (ITS), <italic>SSU</italic>, <italic>LSU</italic>, <italic>TEF</italic>, <italic>RPB1</italic>, and <italic>RPB2</italic> genes.</p></sec><sec><title>Results</title><p>Six genes were used to reconstruct <italic>Lecanicillium</italic> genus phylogeny. The results showed that ITS, <italic>TEF</italic>, <italic>RPB1</italic>, and <italic>RPB2</italic> could be used to identify the strains. All phylogenetic trees reconstructed by free combination of these four genes exhibited almost the same topology. Bioassay studies of a purified conidial suspension further confirmed the infection of second-instar nymphs and adult female <italic>F. occidentalis</italic> by seven <italic>Lecanicillium</italic> strains. <italic>L. attenuatum</italic> strain GZUIFR-lun1405 was the most virulent, killing approximately 91.67% <italic>F. occidentalis</italic> adults and 76.67% nymphs after a 7-day exposure. <italic>L. attenuatum</italic> strain GZUIFR-lun1405 and <italic>L. cauligalbarum</italic> strain GZUIFR-ZHJ01 were selected to compare the fungal effects on the number of eggs laid by <italic>F. occidentalis</italic>. The number of <italic>F. occidentalis</italic> nymphs significantly decreased when <italic>F. occidentalis</italic> adults were treated with <italic>L. cauligalbarum</italic> strain GZUIFR-ZHJ01.</p></sec><sec><title>Conclusions</title><p>The combination of ITS and <italic>RPB1</italic> could be used for fast recognition of <italic>Lecanicillium</italic> spp. This is the first report of the pathogenicity of <italic>L. attenuatum</italic>, <italic>L. cauligalbarum</italic>, <italic>L araneogenum</italic>, and <italic>L. aphanocladii</italic> against <italic>F. occidentalis</italic>. Additionally, <italic>L. cauligalbarum</italic> strain GZUIFR-ZHJ01 caused high <italic>F. occidentalis</italic> mortality and inhibited the fecundity of the pest.</p></sec>