Study On Physiological Characteristics And Transcriptomics Of Cassava Resistance To Bacterial Wilt

Cassava(Manihot esculenta Crantz)is one of the world's three major potatoes,with rich root starch content,often used as a raw material for starch and alcohol processing.The main planting areas for cassava cultivation in China are mainly in South China.During the growth period,it is hot and rainy,which may easily cause diseases such as cassava bacterial wilt.In this experiment,Xin Xuan048 and GR891 were used as test materials.The bacterial pathogen of bacterial wilt was artificially inoculated by acupuncture,and the cassava seedling stage(June 21,June 28)and tuber formation period(August 21 st,August 28th)Sampling and determination of internal substances and related defensive enzyme activities and transcriptomics analysis yielded the following results:(1)In this researchment,the resistance of two cassava varieties to bacterial wilt was identified.The disease index of the Xin Xuan048 was <GR891,the Xin Xuan048 showed medium resistance(MR),and GR891 showed susceptibility(s).(2)Correlation analysis results showed that the disease index was significantly positively correlated with PRO content,PPO activity,POD activityand CAT activity,and negatively correlated with MDA.Soluble sugar content was significantly positively correlated with SOD activity;PPO activity was significantly positively correlated with POD and CAT activity;POD activity was significantly positively correlated with CAT activity.That is,MDA content,PPO,POD,and CAT can be used as physiological indicators for the evaluation of cassava resistance to bacterial wilt.(3)The transcriptome sequencing of the newly selected 048 and control samples was analyzed after 7 days of acupuncture infection,and 39.63 Gb Clean Data was obtained.The Clean Data of each sample was above 6.26 Gb.A total of 32088 expressed genes were detected and a total of 56898 expressed transcripts Pcs.Among them,1932 and 1313 genes were up-and down-regulated.(4)Enriched by GO function in the sample CK vs QR,the main enriched GO body is biological processes and cellular components,mainly including GO items such as metabolic processes,cells,cell membranes,that is,genes induced after cassava inoculation with pathogens are mainly involved in regulation Metabolic pathways and cellular processes at the molecular level.(5)In the sample CK vs QR,the significantly enriched pathway entries of up-regulated genes are mainly in phenylpropane biosynthesis,phenylalanine metabolism,arginine and proline metabolism,and signal transduction,while down-regulated genes are significantly enriched to The pathway entries mainly include photosynthesis-antenna protein,photosynthesis,etc.,indicating that the changes of PPO,POD,CAT and other enzyme activities after cassava inoculation with bacterial wilt are closely related to gene regulation.(6)WRKY31,WRKY40,WRKY47 and other transcription factors in the WRKY transcription factor family participate in transcription regulation,transcription factor activity,sequence-specific DNA binding and play a positive role in the resistance of cassava to bacterial wilt;MYB transcription factors are mainly involved in the metabolic process It is involved in the disease resistanceprocess in the MAPK signaling pathway;b ZIP transcription factors are inseparable from disease resistance by causing plant hormone secretion.