β-Poly(L-malic acid)(PMLA)is a water-soluble biopolymer used in food,medicine and other industries.To date,the biosynthesis pathway of PMLA has not been fully elucidated.In this study,we sequenced the transcriptom e ...β-Poly(L-malic acid)(PMLA)is a water-soluble biopolymer used in food,medicine and other industries.To date,the biosynthesis pathway of PMLA has not been fully elucidated.In this study,we sequenced the transcriptom e of strain Aureobasidium melanogenum under 20 g/L CaCO_(3) addition.The resulting sequencing reads were assembled and annotated for the differentially expressed genes(DEGs)analysis and novel transcripts identification.The result indicated that with the CaCO_(3) addition,the tricarboxylic cycle(TCA)cycle and glyoxylate pathway were up-regulated,and it also found that a non-ribosomal peptide synthetase(NRPS)like protein was highly expressed.The DEGs analysis showed a high expression level of malate dehydrogenase(MDHC)and phosphoenolpyruvate carboxykinase(PCKA)in the CaCO_(3) group,which indicated a cytosolic malate activity.We speculated that the malate should be transported to or synthesized in the cytoplasm,which was then polymerized to PMLA by the NRPS-like protein,accompanied by the up-regulated TCA cycle providing ATP for the polymerization.Depending on the analysis,we assumed that an NRPS-like protein,the TCA cycle,and the cytosolic malate together are contributing to the PMLA biosynthesis.展开更多
基金the financial support of the Tianjin Municipal Science and Technology Commission(17PTGCCX00190,17PTSYJC00080,17YFCZZC00310,and 16YFXTSF00460)the Tianjin Engineering Research Center of Microbial Metabolism and Fermentation Process Control(ZXKF20180301).
文摘β-Poly(L-malic acid)(PMLA)is a water-soluble biopolymer used in food,medicine and other industries.To date,the biosynthesis pathway of PMLA has not been fully elucidated.In this study,we sequenced the transcriptom e of strain Aureobasidium melanogenum under 20 g/L CaCO_(3) addition.The resulting sequencing reads were assembled and annotated for the differentially expressed genes(DEGs)analysis and novel transcripts identification.The result indicated that with the CaCO_(3) addition,the tricarboxylic cycle(TCA)cycle and glyoxylate pathway were up-regulated,and it also found that a non-ribosomal peptide synthetase(NRPS)like protein was highly expressed.The DEGs analysis showed a high expression level of malate dehydrogenase(MDHC)and phosphoenolpyruvate carboxykinase(PCKA)in the CaCO_(3) group,which indicated a cytosolic malate activity.We speculated that the malate should be transported to or synthesized in the cytoplasm,which was then polymerized to PMLA by the NRPS-like protein,accompanied by the up-regulated TCA cycle providing ATP for the polymerization.Depending on the analysis,we assumed that an NRPS-like protein,the TCA cycle,and the cytosolic malate together are contributing to the PMLA biosynthesis.
