Screening and stability verification of reference genes in <i>Botrytis cinerea</i> ZX2 fermentation

<i>Botrytis cinerea</i>, an airborne plant pathogen, holds the potential to synthesize sesquiterpenes, which have been used for the industrial production of abscisic acid. Previously, through our genetic technology, we obtained strain ZX2, whose main product 1´,4´-<i>trans</i>-ABA-diol is physiologically active in plants. In this study, 50 L of fed fermentation was carried out with ZX2 strain to study the stability of expression of <i>TUA</i>, <i>TUB</i>, <i>ATC</i>, <i>EF-1</i>, <i>GAPDH</i>, <i>UCE</i> and <i>GTP</i> genes. Four kinds of software (GeNorm, NormFinder, BestKeeper and Delta Ct) were used to analyze the expression stability of candidate genes, and finally the best reference gene was screened by RefFinder. Based on the results, the <i>ACT</i> was the most stable gene. It was used to normalize the expression levels of two genes related to 1´,4´-<i>trans</i>-ABA-diol production (<i>hmgr</i> and <i>bcaba3</i>) when fed-batch fermentation. Guide the selection of appropriate internal reference genes during the fermentation process to accurately quantify the relative transcription levels of target genes in <i>B.cinerea</i> ZX2.