AUTHOR=Wang Xuegui , Gong Changwei , Zhao Yun , Shen Litao 

TITLE=Transcriptome and Resistance-Related Genes Analysis of Botrytis cinerea B05.10 Strain to Different Selective Pressures of Cyprodinil and Fenhexamid

JOURNAL=Frontiers in Microbiology

VOLUME=9

YEAR=2018

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2018.02591

DOI=10.3389/fmicb.2018.02591

ISSN=1664-302X

ABSTRACT=<p>The pathogen <italic>Botrytis cinerea</italic> is a very dangerous pathogen that infects many economically important crops such as grape, strawberry, tomato, and eggplant. Cyprodinil, a pyrimidine amine fungicide, and fenhexamid, an amide fungicide, are new reagents for controlling gray mold with special efficacy. It is necessary to understand the change trends in the toxicological and physiological characteristics of <italic>B. cinerea</italic> with successive selective pressures of cyprodinil and fenhexamid to elongate the serving life of these fungicides for effective disease control. The toxicities of cyprodinil and fenhexamid at successive concentrations of EC<sub>25</sub>, EC<sub>50</sub> and EC<sub>75</sub> on <italic>B. cinerea</italic> strain BO5.10 were assayed along with mycelial growth-inhibition capacity. The results showed that the EC<sub>50</sub> value of the cyprodinil-treated F<sub>27</sub> strain increased approximately 18-fold, whereas of which in the fenhexamid-treated F<sub>27</sub> strain increased only 3-fold compared with that of the F<sub>0</sub> strain. The conductivities and glycerinum contents of the strains resistant to cyprodinil and fenhexamid were obviously enhanced; in contrast, the oxalic acid contents were decreased compared with those in the F<sub>0</sub> strain. The transcriptomes of the F<sub>27</sub> control (T01), cyprodinil-treated (T02) and fenhexamid- treated (T03) strains were analyzed, and the expression levels of functional genes in the T02 and T03 strains were significantly increased compared with those in the T01 strain; these results were further validated using qRT-PCR. The results indicated that the relative expression of two genes encoding mixed-functional oxidases (MFOs) <italic>BC1G_16062</italic> and <italic>BC1G_16084</italic>, two genes encoding transmembrane proteins <italic>BC1G_12366</italic> and <italic>BC1G_13768</italic>, two genes encoding Zinc finger proteins <italic>BC1G_13764</italic> and <italic>BC1G_10483</italic>,one gene encoding citrate synthase enzyme <italic>BC1G_09151</italic>, one gene encoding gluconolactonase <italic>BC1G_15612</italic> in the T02 and T03 strains and one gene encoding lysophospholipids enzyme <italic>BC1G_04893</italic> in the T3 strain increased substantially compared with that in the T1 strain (<italic>P</italic> &lt; 0.01). Functional prediction analysis of upregulated gene expression and structural verification was also performed, and the results showed that <italic>BC1G_10483</italic> was a ZnF_C2HC transcriptional regulator interacting with the Sp1 element of these genes to respond to the pressures from cyprodinil and fenhexamid. Our results could contribute to a better understanding of the resistance mechanism of <italic>B. cinerea</italic> against cyprodinil and fenhexamid.</p>