草酸青霉转录因子POX03446对生淀粉酶产量调控的初步研究

Preliminary Study on the Regulation of Raw Starch-degrading Enzyme Production of Penicillium oxalicum by Transcription Factor POX03446

生淀粉酶可以在淀粉糊化温度以下的温度下直接降解生淀粉,具有巨大应用价值。丝状真菌生淀粉酶的产生受转录因子的严格调控。但是,草酸青霉(Penicillium oxalicum)中生淀粉酶产生的调控机制仍不清楚。前期工作中,通过比较基因组学获得了草酸青霉HP7-1中调控生淀粉酶产量的候选调控基因集。本研究以草酸青霉ΔPoxKu70为出发菌株,用同源重组技术敲除了其中一个候选调控基因POX03446,获得了缺失突变株ΔPOX03446。在可溶性淀粉培养条件下,与出发菌株ΔPoxKu70相比,转接后第2天,ΔPOX03446的生淀粉酶产量显著下降29.8%~40.3%(p<0.01;Student’s t test);转接后第4天,生淀粉酶产量显著下降14.6%~29.7%(p<0.01;Student’s t test),表明基因POX03446正向调控草酸青霉生淀粉酶的产生。NCBI BlastP比对分析显示POX03446与草酸青霉调控木聚糖酶基因和纤维素酶基因表达的转录因子PoXlnR一致性为46%。这是第一次报道POX03446调控草酸青霉生淀粉酶的产生。

Raw starch-degrading enzymes(RSDEs) are capable of directly degrading raw starch granules below the gelatinization temperature of starch,and have a great application value.RSDEs productions by filamentous fungi is tightly regulated by transcription factors.However,the regulatory mechanism of RSDEs production remains unclear in Penicillium oxalicum until now.In the previous work,candidate genes for regulating RSDEs production were screened through comparative transcriptiomic analyses of P.oxalicum strain HP7-1.In this work,in P.oxalicum ΔPoxKu70 used as the parental strain,a candidate gene POX03446 was knocked-out to generate the deletion mutant ΔPOX03446 by using homologous recombination.Under the induction of souble starch,RSDEs production of the mutant ΔPOX03446 decreased by 29.8%~40.3%(p<0.01;Student’s t test) as compared with that of the ΔPoxKu70 on day 2 after transfer from glucose.Similarly,RSDEs production of the ΔPOX03446 decreased by14.6%~29.7%(p<0.01;Student’s t test) on day 4,suggesting that POX03446 positively regulates RSDEs production in P.oxalicum.NCBI BlastP analysis revealed that POX03446 shared 46% identity with transcription factor PoXlnR regulating expression of genes encoding cellulase and xylanase in P.oxalicum.This is the first time to report the regulatory roles of POX03446 in the RSDEs production of P.oxalicum.