Identification And Prevention Of Pathogenic Fungus Of Rhizome Rot Disease In Ginger

Ginger rhizome rot was a typical soil-borne and seed-propagation disease,the cure methods of it were mainly based on chemical pesticides and fertilizers.It is imperative to develop alternative type of environmental-friendly medical.Ginger cultivation in Shandong had a long history,with the expansion of ginger planting area in recent years,ginger disease also showed a trend of rise,especially ginger rhizome rot bring farmers huge economic losses.Ginger rhizome rot had become one of the main problems of ginger production.Morphological observation、 pathogenic determination and sequence analysis were taken in this study to determine the pathogen in ginger.Fungicide selection indoor and field experiment were also taken in this study to offer theoretical basis to the control of ginger rhizome rot.The main results were as follows:1.More than 60 gingers with rhizome rot were selected from different areas in Anqiu,Shandong Province.After purification and pathogenic determination,the pathogen Pythium spp.Conformed to Koch’s postulation.Three different kinds of pathogens were obtained after morphology observation and rDNA-ITS analysis,including Pythium spinosum,P.myriotylum and P.sylvaticum.2.To clarify the antibacterial effect of chitosan against those pathogen,the test in vitro and in vivo was used.The results showed that the pathogen of ginger rot disease in Shandong was identified as P.myriotylum、P.spinosum and P.sylvaticum,the mycelial growths of those pathogen were restrained by chitosan and the EC50 values were 422.7112 mg/L,401.6995 mg/L and 446.9107 mg/L.3.Microscopic observation photographic techniques are used to observe chitosan treated pythium mycelial morphology changes in this study.Micrography observation showed,while inoculated in the substrate with chitosan,the mycelia would abnormally grow,such as bulging,contorting,more branches,vacuolation in mycelia.4.Using the transcriptome sequencing technology compared chitosan treatment group with control group of pythium expression differences of pathogenic bacteria and the control group of differentially expressed genes has carried on the statistical analysis,the results received a total of 770 differentially expressed genes,including 237 up-regulated genes,533 down-regulatedgenes.Differentially expressed genes with the GO database and KEGG database compare notes,after enrichment of function,found that some involves transmembrane transport related genes and some related with the transmembrane transport of enzyme activity change.5.The conventional soil sample separation method was used to determine the content of ginger pythium in Anqiu and Changyi.The determination results is that pythium content in per gram sane soil is 1-100,the serious illness soil bacteria content is 800-2500 per gram.Results showed that the higher pythium bacteria content,the heavier ginger rhizome rot disease.6.A growth rate method was used to verify the antifungal activity of ten essential oils against three species of pathogenic pythium.Four broad-spectrum antimicrobial activity of plant essential oil were selected,including Bay essential oil,Cinnamon essential oil,Geranium essential oil and Eugenol oil.Eugenol oil had high inhibitory activity against the tested fungal at 50 mg/L,with the inhibition rate over 50%.At 150 mg/L,four biological agent had the inhibiton rate aginist three pythium over 50%~100%.7.Field control technology was used to study the effect of chitosan on ginger rhizome rot disease.Results showed that: compared with control group,the control effect of chitosan to ginger rhizome rot disease could reach 98.02% and the production increased 51.14%.Compared with other agentia,chitosan could prevent the happening of ginger rhizome rot disease obviously,thus improve the production.Chitosan had superiority of employ.