Effects Of Some Plant Growth-promoting Rhizobacteria Volatiles On Arabidopsis And Antagonistic Properties

To study the effects of plant growth-promoting rhizobacteria volatiles on arabidopsisthaliana, the collection and separation strains in this lab with the model plant arabidopsisthaliana (wild type Col-0) co-cultured, the role of the strains in screening out by the methodof divided Petri dishes, and to assess the screened strains antibacterial activity, the strainsrespectively with Phytophthora parasitica, Pseudoperonospora cubensis, Fusariumoxysporum f.sp cucumerinum Owen and Fusarium solani co-cultured by the method ofdivided Petri dishes also. The screened strains sealed cultured by Shaker, collected andanalysised the volatiles prduced of the strains by SPME-GC-MS, several detected compoundswere made growth promoting and antibacterial experiments, and discussion the role of asingle compound.We studied60different species of bacteria in the test, and screened out13strains ofbacteria have an effect on the growth of arabidopsis thaliana by the method of divided Petridishes, They are MTQ8, TZQ33, WCH1, MD8, DZQ8, TZQ2, TZQ14, YQH50, YQH58,DZH3, FGH19, P1and TZQ36, respectively，based on the morphological and BLASTsearches on the NCBI data libraries for similarities of the16S rDNA sequences, the13strainswere identified as Enterobacter endosymbiont, Bacillus cereus, Geobacillusstearothermophilus, Pseudomonas chlororaphis, Pseudomonas putida, Bacillus thuringiensis,Pseudomonas putida, Serratia sp., Bacillus pumilus, Brevibacillus brevis, Enterobactercancerogenus, Bacillus megaterium and Bacillus megaterium, respectively.The VOCs produced by the13strains can promote growth and modulate root-systemarchitecture of Arabidopsis in different degree by using specialy divided plastic petir dishes.Effects of volatiles produced by P1, MD8and FGH19strains on Arabidopsis are veryremarkable, with average Arabidopsis thaliana fresh weight38.78,30.58and23.70mg/strains respectively, increased5.71,4.29and3.10times compared with the control, respectively. PRL of Arabidopsis line with DZQ8treated is8.03cm, increasing0.85timescompared to the control ones.The LRN of Arabidopsis with TZQ33and TZQ36treated weremore obviously,37.50and40.50, respectively, increasing1.17and1.35times. the LRD ofMTQ8、MD8、TZQ33and TZQ36treated Arabidopsis were6.20、7.07、7.35and7.33cm-1,respectively, and increased0.55、0.77、0.84and0.83times compared to the control. TheVOCs produced by the13strains can inhibit Phytophthora parasitica in different degree,individual strains for a variety of pathogenic have inhibition. The VOCs produced by TZQ33has inhibition to Pseudoperonospora cubensis, the VOCs produced by TZQ36, DZQ8andTZQ2have slight inhibition to Fusarium oxysporum f.sp cucumerinum Owen.Based on the analysis of volatile organic compounds by SPMS-GC-MS, aldehydes,ketones, alcohols, acids, esters, hydrocarbons, sulfur were the most abundant compoundclasses in the VOCs produced by the13strains. Based on the test of purified gas effect on thegrowth of arabidopsis thaliana, we are the first to discovered that1,3-Butanediol produced byMTQ8can obviously promote growth of Arabidopsis, acid have no role on the growth ofarabidopsis plants, decanal not only inhibit the growth of pathogenic bacteria, but also hasstrong toxic for arabidopsis, the role of the compounds remains to be further research.This research showed that the VOCs produced by PGPR play an important role assignaling molecules between bacteria and plants, they can not only promote the growth ofarabidopsis thaliana, and modulate root-system architecture, but also inhibit the growth ofsome pathogenic.