| Pleurotus tuoliensis was first discovered in northern Xinjiang.It is one of the rare edible fungi independently domesticated and named by Chinese experts.It has anti-inflammatory and anticancer effects and belongs to the middle-low temperature type of edible fungi.The most notable feature of the plant is that it must undergo a low temperature induction to enable primordium formation and fruiting body development.In this study,the strain "Zhongnong no.1" was used as the experimental material for low temperature induction.Four treatment groups were set for the same batch of activated strains according to the sequence of culture stage(each treatment group collected mycelia or primordia on the basis of the treatment group in the previous stage).Mycelia cultured at 25℃ for 7 d,mycelia cultured at 4℃ for 3 d,mycelia cultured at 16℃ with 12 h light /12 h darkness alternately for 7 d and primordia formed by 7 d were represented by CK,T1,T2 and T3,respectively.By measuring the changes of physiological indexes and the differences of gene expression in the process of primordia formation,the molecular mechanism of primordia formation induced by low temperature was preliminarily revealed.The test results are as follows:1.MDA content decreased first and then increased during low temperature induction,which was consistent with conductivity measurement results.The activities of three protective enzymes(SOD,POD and CAT)increased first and then decreased,and the SOD activity in T1 treatment group was the highest,increasing by 11%.Compared with CK,POD activity in T1 treatment group was significantly increased(P <0.05),from 29.92 U/(g ·min)to 73.12 U/(g ·min).There was no significant difference in CAT activity between T1 and T2 treatment groups,but it was significantly higher than CK(P <0.05).ROS accumulation was most obvious in T1 treatment group,indicating that ROS accumulation was closely related to protective enzyme activity.The content of soluble sugar increased and then decreased,and the content of soluble sugar in all treatment groups was significantly higher than that in control group(P <0.05).The content of free proline in all treatment groups was significantly different(P <0.05),and the content of free proline in T1 treatment group was the highest.Comprehensive analysis showed that the activities of three protective enzymes,ROS accumulation and distribution,MDA content,free proline content,electrical conductivity,soluble sugar and soluble protein content all changed during low temperature induction,among which the activities of protective enzymes,soluble protein content and free proline content changed greatly under low temperature.2.The GO function enrichment of differential genes was only reflected in the comparison group of T3 and T2,and the significantly differentially expressed genes found in the comparison group were enriched in 65 up-regulated genes and 74down-regulated genes(P <0.05),and all were enriched in molecular functions.These results indicate that the formation of the primordia is closely related to the differential expression of genes such as heme binding,REDOX enzyme activity,tetrapyrrole binding and iron ion binding.In the analysis of 20 pathway items with the most significant enrichment in KEGG pathway,T1 vs CK was enriched in 27 up-regulated genes and 9 down-regulated genes.T2 vs T1 was enriched to 21 up-regulated genes and 23 down-regulated genes.T3 vs T2 was enriched in 24 up-regulated genes and 60down-regulated genes(P <0.05).Enrichment of these differentially expressed genes to access cover material synthesis and metabolism,oxygen,sugar conversion and transport,signal transduction,REDOX enzyme activity,amino acid metabolism,ribosomes and monitoring of the RNA and cell cycle regulation,and other aspects,this shows that in low temperature environment spirit give ear primordia formation mechanism by a variety of common control,They are the key to primordia formation. |
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