Study On Effects Of Cadmium Stress On Growth And Cold Resistance Of Pirata Subpiraticus

This paper explores the effects of heavy metal cadmium on the cold resistance of the dominant rice species Pirata subpiraticus,and explores its possible mechanism through high-throughput sequencing technology.The main findings are as follows:1.Cadmium stress has an adverse effect on the growth and development of Pirata subpiraticus.The total developmental period of cadmium stress group was 57±1.8212 days,slightly longer than that of the control group of 54.7±1.2103 days.The cadmium stress group 5-7th instar spiderlings carapace width,body length,weight,and middle eye width were significantly lower than the control group(P<0.01).2.Cadmium stress has an effect on the metabolism of nutrients in the hemolymph of Pirata subpiraticus.It is found that the content of protein,sugar and fat in the hemolymph of normal spiders is lower than that of cadmium-stressed spiders;Low temperature(4℃)stimulation had an effect on the metabolism of nutrients in the hemolymph of Pirata subpiraticus.It was found that the protein,sugar and fat content in the hemolymph of the spider was higher than that at 25℃ at 4℃;Cadmium stress and low temperature stimulation have an adverse effect on the mortality of Pirata subpiraticus.At 25℃,instar is the main factor affecting the mortality of Pirata subpiraticus.Cadmium stress is a secondary factor,temperature is 8℃,4 ℃ and 0℃,cadmium stress is the main factor affecting the mortality of Pirata subpiraticus,and instar is a secondary factor.3.Comparison of gene expression in Pirata subpiraticus’ spiderling with or without cadmium stress at low temperature,and the differentially expressed genes were analyzed by GO and KEGG enrichment.It was found that the up-regulated differential genes of spiderlings are mainly enriched in metabolism in GO(oxidoreductase activity,redox process,lipid transport),Stress(biostimulatory response,response to external biostimulation,negative regulation of stimuli),and enzyme activity(glutamyl-t RNA reductase activity,cysteine peptidase activity,oxidoreductase activity),It indicated that heavy metal cadmium had an effect on the metabolism,stress and enzyme activity of spiderling.Down-regulation of differential genes is mainly enriched in metabolism(antibiotic biosynthesis process),suggesting that cadmium may affect the resistance of spiderlings at low temperatures.In KEGG,up-regulation of differential genes main enrichment pathways in apoptosis and lysosomes,indicating that cadmium stress and low temperature treatment conditions can promote the gene expression of apoptosis and lysosomal.Down-regulation of the main enrichment pathway in the biosynthesis of steroid hormones,suggest that cadmium may affect theimmune regulation and regulation of ecdysis of spiderlings at low temperatures.4.Comparison of gene expression in Pirata subpiraticus’ mature spider with or without cadmium stress at low temperature,and the differentially expressed genes were analyzed by GO enrichment.It was found that the up-regulated differential genes of mature spider are mainly enriched in stress in GO(cellular response to chemical stimulus,flavin-containing compound metabolic process),It is indicated that cadmium may have an effect on the sensory and nervous system of Pirata subpiraticus.Down-regulation of differential genes is mainly enriched in terms of metabolism(nucleotide catabolism,proteolysis)and enzyme activity(metal peptidase activity,hydrolase activity),It is indicated that heavy metal cadmium may affect the growth of mature spiders’ nutrient,metallopeptidease activity and hydrolase activity at low temperature.