Differences In Rhizospheric And Endophytic Microbial Characteristics Of Chinese Flowering Cabbage (Brassica Parachinensis) With High/Low Ciprofloxacin Accumulation

As a kind of emerging persistent organic pollutant(POPs),antibiotics have been extensively detected in the field of agricultural environments,also easily to be accumulated in the vegetable.At present,it is important for promoting the development of clean agriculture and ensuring the safe of the agricultural products quantity to research the mechanism of difference between highand low-antibiotic crop cultivars.Rhizospheric and endophytic microbe were showed the significant influences in plant physiological and biochemical process and absorption and accumulation of POPs.Then,differences in rhizospheric and endophytic microbial characteristics of Chinese flowering cabbage with high/low ciprofloxacin accumulation were studied to revealed its influences to variation and Mechanisms of absorpting and accumulating CIP between two cultivars.In the present study,we choiced Chinese flowering cabbage(Brassica parachinensis L.)as the research object,and high ciprofloxacin(CIP)accumulator(Youqingsijiu,S)and low CIP accumulator(Youlvcutai,C)of Chinese flowering cabbage cultivars were screened out by pot culture under different pollution levels of CIP which was the fluoroquinolone antibiotics(FQs).Genetic similarity coefficient of cultivar of “S” and “C” was 0.921,indicating that they had the very closed germplasm genetic distance and shared a common ancestry.The comparative analysis of microbial community structure characteristics of sterile culture seedlings and systems of Chinese flowering cabbages-soils between the high/low accumulating cultivars showed that the significant variations in each parts of between S and C cultivars under the different treatments of CIP,the degrees of sensitivity were variety in different parts.The bacterial communities had the higher sensitivity and a large variation than fungal communities.Correlation analysis found that some of bacterial and fungal genus were significant positive or negative correlation with concentration of CIP.Bacterial genus of Achromobacter,Brevundimonas,Arenimonas,Flavisolibacter,Flavobacterium,Fluviicola,Georgenia,Methanosarcina,Streptomyces and fungal of Ascobolus,Monographella,Peyronellaea,Rhizophlyctis,Trichocladium,Trichosporon were the positively correlated.Acinetobacter,Bacterial genus of Adhaeribacter,Brevibacillus,Bacillus,Bdellovibrio,Clostridium,Exiguobacterium,Gallionella,Geobacter,Hymenobacter,Kaistobacter,Microbacterium,Paracoccus,Phenylobacterium,Pseudomonas,Rhodoplanes,Sphingomonas,Wautersiella and fungal of Zopfiella were negatively correlated,respectively.Therein,these fungal genus were found in systems of Chinese flowering cabbages and soils but absent in sterile culture seedlings,and had the highest relative abundance in rhizosphere-soil,significant differences between two cultivars,showed that system of Chinese flowering cabbages and soils was easy to increase the activation of fungal genus associated with CIP.The differences of distribution and relative abundance of these genus indicated that they could be the key factors lead to the different accumulation between two cultivars.Meanwhile,the analysis of the carbon source utilization efficiency of rhizospheric microorganism between two cultivars showed that the significant variations under different treatments of CIP,the Sole-carbon-source utilization also were diverse.Significant differences of activity between rhizosphere microbe of high and low accumulating cultivars were found in high CIP treatments,and high accumulating cultivars had the lower activity.These differences also may be the important factor to lead to variation of CIP in rhizosphere and plant between two cultivars.Base on the combination of high-throughput sequencing and metagenomic analysis,the changing characteristics of microbial community in the rhizosphere and plant between high and low accumulating cultivars of Chinese flowering cabbage were discovered primarily in this study,some microbes which associative with CIP were screened.These results provide basis on cultivation of the functional microbes and illuminating the microbial mechanism of variation on CIP accumulating between two cultivars of Chinese flowering cabbage.