Abstract:Penicillium oxalicum is an important biocontrol microbe in plants. A linear pentapeptide was isolated from P. oxalicum distributed in the Three Gorges river bank, and it had an extremely strong inhibitory effect on P. Digitatum, a pathogen causing citrus rot. In order to explore the biosynthesis mechanism of linear pentapeptide, the cDNA libraries of three P. oxalicum strains (114-2, SG-4, SJ-3) with different pentapeptide contents were sequenced by the BGISEQ-500 platform, and the results were compared with the reference transcriptome. High-throughput sequencing produced 6.55 GB of data averagely, and the alignment rate with the reference transcriptome reached 91.65%. Compared with 114-2 without pentapeptide production, comparative analysis of differentially expressed genes showed that a total of 1 648 genes were up-regulated and 1 251 genes were down-regulated in SG-4 and SJ-3 that could produce pentapeptide. AntiSMASH analysis suggested that there might be 33 non-ribosomal peptide synthetases (NRPS) genes in P. oxalicum genome, among which the expression of 15 NRPS was consistent with that of pentapeptide. Further RT-PCR expression analysis showed that the gene cluster PDE_01071 might be responsible for pentapeptide synthesis.
