The Influence Of Autophagy On Lipid Accumulation In Rhodosporidium Toruloides

The scientists all over the world develop renewable resources and environmental-friendly fuels to solving the worldwide problems such as shortage of energy supply situation and serious environment pollution.The biodiesel converted from biomass is one of the most ideal renewable fuels.The microorganisms in nutrition limitation will lead to cell autophagy and lipid accumulation at the same time,and cell autophagy and lipid accumulation are both hotspots recently.Although many scholars found that in the model yeast—Saccharomyces cerevisiae the cell autophagy has positive relationship with lipid accumulation,which kind of correlation between autophagy and lipid accumulation in the oleaginous yeast needs further incestigation.In order to study the above-mentioned correlation,we construct the RNA interference(RNAi)vector to knock down the autophagy-related gene.ATG8 and ATG9 in the red yeast Rhodosporidium toruloides NP11 by Agrobacterium tumefaciens-mediated transformation(ATMT),and got 5 recombinant strains:A9-1,A9-2,A9-3,A8-1 and A8-2.The data showed that,target gene decreased significantly at transcription level through reverse-transcription polymerase chain reaction(RT-PCR),and the activity of autophagy was restricted by the method of staining the autophagosome.At the same time the lipid content of engineering strains is significantly lower than the wild type strain,dropping from 65%to 40%.On the other hand,we construct the RNAi vector to knock down the FAS1 which is the key gene in lipid synthetic pathway and got the engineering strains:F-1 and F-2.The target gene decreased significantly at transcription level through RT-PCR,and the activity of autophagy restricted by the method of staining the autophagosome.The lipid content of engineering strains is significantly lower than the wild type and the ATG-RNAi engineering strains,dropping from 65%to 20%.In conclusion,the weakened activity of autophagy lead the low content of lipid,and inhibitingthe lipid synthesis lead the feeble activity of autophagy.Thus,the lipid content and autophagy act on each other.