Effects Of Differe Nt Regulation Treatments On Lignification Of Stored Pleurotus Eryngii

With the advance of commercial cultureofPleurotus eryngii and the increase of market demand,the yield ofPleurotus eryngiiincreased significantly.The preservation of storage quality of fresh mushroom has become a key link in Pleurotus eryngii industry.O ur previous study found thatPleurotus eryngii stored at low temperature easily occurred lignification deterioration,which significantly reduced the edible and commercial value of Pleurotus eryngii.In this study,genes involved in lignin biosynthesis were cloned based on our previous study.The effects of different regulation treatments on two lignification of stored Pleurotus eryngiiwere studiedfrom physical and chemical level and gene expression level to explore the inducement factors of two lignification.The results will serve as a valuable resource for further investigation of the lignification of Pleurotus eryngii.The main results are as follows:?1?Fresh king oyster mushrooms in active modified atmosphere packaging with different initial gas compositions?vacuum,5%oxygen+10%carbon dioxide+nitrogen,80%oxygen+5%carbon dioxide+nitrogen?were stored at 4?for 18 days to analyzethe change of textural attribute,polyphenols and flavonoidcontent and antioxidant activity.The results showed that the relevant indicators of two lignifications of Pleurotus eryngii under three MAP storage conditions were significantly changed.The firmness of fruiting body was affected by CO₂ concentration.The O2 concentration could significantly affect the change of toughness.And different MAP storage conditions could change the typical two postharvest lignifications characteristics of Pleurotus eryngii.To view the situation on the whole,the change tendency of polyphenols contents was positive correlation with the three indicators of lignification during 3-15 days storage under three regulation treatments,but the change tendency of flavonoids contents was negatively correlation with these indicators.?2?Fresh king oyster mushrooms,packed in low-density polyethylene bags,were stored at different low temperatures?1?,4?and 8??for 18 days to analyze the effects of temperature regulation on the changes of lignin content,firmness and toughness.The results showed that the lignin content,firmness and toughness of fruiting bodies increased obviously twice during whole storage under different temperature regulation,which presented typical two postharvest lignification of Pleurotus eryngii.With the decrease of storage temperature,the three lignification indicators increased significantly.And the second lignification was higher than the first lignification.?3?Fourgenes related to lignin synthesis?named PePLA1,PeCAD1,PeCAD2andPeC4H,respectively?were cloned from Pleurotus eryngiiby RT-PCR technology.The CDS?coding DN A sequence?size of PePLA1 was estimated to be 2244bp,encoding a polypeptide of 747 amino acids.The CDSsize of PeCAD1was estimated to be 1065bp,encoding a polypeptide of 345 amino acids.The CDSsize of PeCAD2was estimated to be1065bp,encoding a polypeptide of 345 amino acids.The CDSsize of PeC4Hwas estimated to be 1623bp,encoding a polypeptide of 540 amino acids.?4?Five genes cloned by our previous and this studies were selected to analyze the expression patterns in different parts of fruiting body under different storage periods?1??4?and 8??by quantitative PC R?q RT-PCR?technology using?-actin as reference gene.The results showed thatPePLA1,PeCAD1 andPeCAD2 exhibited the lowest expression levels in the bottom part of fruiting body,whilethe expression level of PePLA2 was the highest in the bottom part of fruiting body.PePLA1presented the similar expression pattern withPeC4H?up-down-up-down?during storage under three regulation treatments,change tendency of which was positive correlative with lignin content,firmness and toughness.During 3-18 days,the change tendency of the expression pattern of PeCAD1and PeCAD2was positive correlative with lignification indicators.