Study On Resistance Response Mechanism Of Sansevieria Trifaxciata Var.Laurentii To Indoor Benzene Pollution

Benzene is the top indoor chemical pollutant among the"three invisible killers".Benzene has the characteristics such as persistent and difficult to degrade,with carcinogenic and teratogenic ability.It has been a serious threat to people’s life health.Plants are not only highly sensitive to monitoring indoor chemical pollutants such as benzene,but also have a stable,efficient,consistent and safe purification and restoration effect.Applyling fouling absorption sewageindoor plants has become an effective way and important means to absorb and purify indoor benzene pollution.However,resistance of plants to pollution is the basis and prerequisite for utilization of their ability to absorb pollutants.But the basic biological mechanism of plant resistance to benzene pollution is still unclear.The study of the resistance mechanism of plants to benzene pollution at the cellular and molecular levels will help break the scientific bottleneck in the study of the response mechanism of indoor plants to benzene pollution,and provide a basic theoretical basis and entry point for the selection and cultivation of indoor plants with strong resistance to pollution and pollution absorption in the future.Using closed fumigation test,Sansevieria trifasciata var.laurentii was used as a test material that has a strong capacity of purification and resistance against benzene pollution to study the changes of physiological and biochemical indexes under benzene pollution stress,and to explore the response mechanism of Sansevieria trifasciata var.laurentii to benzene pollution at the cellular level.Transcriptomics techniques were performed to study the key metabolic pathways and signalling pathways in the resistance response of Sansevieria trifasciata var.laurentii.Key genes were identified and their biological functions were clarified,and the molecular response mechanism of Sansevieria trifasciata var.laurentii to benzene pollution was dissected.The main findings are as follows:1.Physiological and Biochemical Resistance Responses of Sansevieria trifasciata var.laurentii to Benzene Pollution.（1）Photosynthetic characteristics,reactive oxygen species and antioxidant enzyme activities,osmoregulatory substance content and cell membrane permeability of Sansevieria trifasciata var.laurentii leaves were different in the comparison between 1 d and 1 d stress treatment（CK0 vs.B）,1 d stress treatment and 7 d recovery（B vs.B7）.In the comparison between 7 d and 7 d recovery（CK7 vs.B7）,there were differences or no differences.It is suggested that Sansevieria trifasciata var.laurentii reacted strongly to the stress after the benzene,and that some indicators gradually returned to normal levels after self-recovery.（2）Under benzene pollution stress,there were different degrees of correlations among the11 indicators in the leaves of Sansevieria trifasciata var.laurentii,suggesting that photosynthetic properties,reactive oxygen species and antioxidant enzymes,osmoregulatory substances and cell membrane permeability jointly regulate the physiological and biochemical responses of Sansevieria trifasciata var.laurentii,which were regulated by a complex and sophisticated system in the body to resist benzene pollution and thus maintain normal growth.（3）Antioxidant enzymes and osmoregulatory substances played a key role in the resistance response to benzene pollution and in the self-recovery of Sansevieria trifasciata var.laurentii.2.Transcriptomic Results of Sansevieria trifasciata var.laurentii to Benzene Pollution.（1）The quality analysis of the transcriptomic data of the Sansevieria trifasciata var.laurentii showed that the sequencing data were stable and of high quality.（2）Sansevieria trifasciata var.laurentii homologous species was Pantholops hodgsonii.The number of functional groups annotated to BP and CC by GO function was the largest,the number of Unigenes annotated to BP was the largest.The KEGG had the largest number of Unigenes functionally annotated as signal transduction.The egg NOG function annotations accounted for the largest proportion of general function predictions.（3）The SSR repeat types with the highest number of Sansevieria trifasciata var.laurentii were single nucleotide,dinucleotide.The repetitive motifs were mainly A/T,AG/CT,AT/AT,AAT/ATT,AAG/CTT.（4）A total of 1563 DEGs were involved in the resistance response of Sansevieria trifasciata var.laurentii,with 549 up-regulated genes and 1014 down-regulated genes.A total of 3977 DEGs participated in the self-recovery of Sansevieria trifasciata var.laurentii,with2478 up-regulated genes and 2820 down-regulated genes.3.Functional Study of Key Genes in Sansevieria trifasciata var.laurentii Resistance Response to Benzene Pollution.（1）The GO entries that were significantly and most abundantly enriched in the resistance response（CK0 vs.B）were catalytic activity,hydrolase activity,and cellular carbohydrate metabolic processes.Self-recovery（B vs.B7）was enriched for significant and most numerous entries for protein heterodimerisation activity,protein folding,and protein dimerisation activity.Significantly enriched and most numerous entries in self-recovery（CK7 vs.B7）were ribonucleoside diphosphate reductase activity,thioredoxin disulfide as acceptor,oxidoreductase activity,acting on CH or CH₂groups,disulfide as acceptor,ribonucleoside-diphosphate reductase activity.（2）Fatty acid biosynthesis pathway and MAPK signaling pathway were key signaling pathways and metabolic pathways to the resistance response.LACS,PP2CA,PP2CB were key genes in plant resistance response.Ascorbate and aldarate metabolism pathway,Porphyrin and chlorophyll metabolism pathway,Circadian entrainmentpathway were key signaling pathways and metabolic pathways to the self-recovery.ALDH,ALDH7A1,hem E,GLR1,GLR2,GLR3,GLR4 were key genes in plant self-recovery.（3）The key genes in the resistance response are mainly involved in binding,cation binding,ion binding,in addition to catalytic activity and molecular function,key genes are mainly enriched in the MAPK signalling pathway and are associated with environmental information processing,mainly signal transduction.In summary,Sansevieria trifasciata var.laurentii maintains its vital activities against benzene pollution through strategies such as modulating ROS detoxification processes,increasing antioxidant enzyme activity,reducing cellular osmotic potential,protecting cell membrane structure and regulating photosynthesis.This complex network of regulation at the physiological and molecular levels is the main response mechanism of Sansevieria trifasciata var.laurentii to indoor benzene pollution.