The Study Of Quorum-sensing Signal Molecular Gene Expression For Hafnia Alvei

Hafnia Alvei is a kind of spoilage bacteria, which could cause food spoilage, like seafood,meat products, dairy products, fruits and vegetables and others. In order to further define the role of quorum sensing mechanism in food spoilage, and to provide a new strategy of food preservation for the quorum sensing system, this study mainly used quantitative PCR technique to study the impact of environmental factors on the relative expression level of Hafnia Alvei quorum sensing signal molecules gene luxI and luxR.In order to study the expression differences of gene luxI and luxR accurately, this paper firstly studied the 16 S rRNA, 23 S rRNA, recA and gapA four candidate reference genes expression under different experimental conditions, and found that their expression in descending order of abundance is 16 S rRNA > 23 S rRNA > recA > gapA. Finally confirmed that the gene 16 S r RNA is the most stable by using NormFinder and Best Keeper program, and used 16 S rRNA as a reference gene for subsequent experiments.The effect of different sodium chloride concentration, pH and temperature on the relative expression level of luxI and luxR gene were studied. The results showed that, with the increase of sodium chloride concentration, the rise of pH value and temperature, the relative expression level of both two gene changes in synchronization. When the sodium chloride concentration is 1%, pH is 7.5 or temperature is 10℃ and 25℃, the expression of luxI and luxR gene is higher. And culture conditions in a sodium chloride concentration above 3%, pH is not 7.5 or the temperature is below 4℃ or above 37℃, the expression of luxI and luxR gene is restrained.