Physiological Basis And Resistance-Related Genes Analysis Of Jackfruit Rust

Jackfruit is a famous tropical fruit with high nutritional value.In recent years,the occurrence of jackfruit rust has gradually become common.The occurrence of rust seriously affects the taste and sweetness of jackfruit,resulting in a certain economic loss.In China,the cause of fruit rust is not clear,and the content related to jackfruit rust is rarely reported.The research on jackfruit rust deserves our in-depth study.This paper investigated the incidence of large-scale jackfruit planting bases in five areas of Hainan Province.The diseased tissue was observed for sectioning and pathogen isolation and detection.At the same time,six physiological indicators related to plant resistance physiology were measured.This study performed transcriptome sequencing of three fruit rust bracts and three healthy fruit bracts in mature "Qiongyin No.1" jackfruit rust fruit.Based on the analysis of transcriptome data to further explore jackfruit rust,the main findings are as follows:1.Investigation revealed that there were no central diseased plants in the field,and the diseased plants were randomly distributed in the field.The occurrence of jackfruit rust in five observation sites was relatively serious in April.The incidence rate in Ding'an was the highest,being 7.38%.The incidence rate in Baoting was the lowest,which was 3.51%.Only sporadic occurrence occurred in October.The incidence rate was highest in Chengmai,only at 5.60%,Qiongzhong had the lowest incidence of 3.20%.Not all fruits are diseased in the diseased fruit trees;the collected fruits are basically mature fruits,and only one young fruit was collected in the planting base in Ding'an County.2.The pathogens were isolated from the susceptible tissue,and no colony growth was observed on the PDA medium and the LB medium and three kinds of special culture medium for Uredinales.3.The PCR amplification reaction was performed using the ITS sequence of the fungus and the bacterial 16S sequence.Compare and analyze the sequencing results,Sequencing of the ITS showed 99.08%sequence identity between rust bracts and healthy bracts and sequencing of the 16S showed 99.52%sequence identity between rust bracts and healthy bracts.4.Selected Apple Scar Skin Viroid(ASSVd),causing fruit rust on apple,as well as the most common viruses infecting tropical plants such as Banana Bunchy Top Virus(BBTV),Cucumber Mosaic Virus(CMV),Papaya Ring Spot Virus,(PRSV),Citrus Exocortis Viroid(CEVd).Using these virus-specific primers for molecular detection of jackfruit fruit rust,no target bands were obtained.5.Used rust bracts and healthy bracts for CAT,POD,PPO,PAL,SOD and MDA 6 kinds of plant resistance related physiological and biochemical index determination.The experimental results show that the rust bracts CAT,POD,SOD and PAL are higher than healthy bracts,healthy bracts PPO activity,MDA are higher than rust bracts,Among them,SOD,CAT,PAL,and MDA can be used as physiological indicators that reflect the differences between rust bracts and healthy bracts in jackfruit.6.Rust bracts and healthy bracts were sequenced and assembled,A total of 88,010 Unigene were obtained,of which 45,139 Unigene were annotated.The results of differential expression were consistent with expectations.There were 2,387 Unigene differential expressions,of which 1,013 were up-regulated and 1,374 were down-regulated.These differential genes annotated 115 KEGG pathways.Through enrichment analysis found that the occurrence of jackfruit fruit rust can stimulate plant immune defense reaction,enzymatic protection system will play a role in the body at the same time,lead to the activity of antioxidant enzyme increases,and the resistance of the experiment research on the effects of physiological characteristics consistent,at the same time for multiple enrichment produced active effect to the metabolic pathways.7.Based on transcriptome data for differential gene expression analysis,it was found that plant-pathogenic interactions and peroxisome pathways are closely related to plant resistance.A total of 15 genes were highly expressed in the two pathways,among which the three genes with the highest expression levels were PEX5(c61906.graph_c3)in the peroxisome pathway,FLS2(c60753.graph_c3)and RPM1(c61818.graph_c0)in the plant-pathogen interaction pathway.The genes play an important role in the resistance response and can be used as target genes for subsequent studies.At the same time,qRT-PCR experiments were performed on 15 genes in these two pathways to verify the reliability of the transcriptome sequencing results.