| Tomato bacterial wilt is a serious soil-borne pathogen and it is a threat on the production and quality of crops.It is a vascular disease that caused by the Ralstonia solanacearum and that widely distributed in tropical,subtropical and temperate regions.That mass using chemical pesticides leads to many problems of environment and health.Therefore,people urgently need to search biological controlling methods for replacing the methods of chemical control to comply with the green,environmental,pollution-free agricultural development direction.Plant essential oils are secondary metabolites.According to the reports,they have good inhibition effect for pathogenic fung and bacteria.In our study,we tested antibacterial activity on R.solanacearum by Chinese Prickly Ash essential oils and its minimum inhibitory concentration(MIC)against R.solanacearum and analysed main components of essential oils by GC-MS and tested growth promoting effect of the oils on tomato and the evaluation of their biocontrol effect towards R.solarnacearum.At last,we checked the changes of volatile components in tomato and the expression of defence genes and then studied the disease resistance mechanism of Chinese Prickly Ash essential oils preliminarily.1.Test antibacterial activity on Ralstonia solanacearum by Chinese Prickly Ash essential oils and analysing main components of essential oils by GC-MSJS10726 as a pathogen indicator bacteria,tested antimicrobial activity of Zanthorylum bungeanum and Zanthoxylum schinifolium oils and minimum inhibitory concentration(MIC)against Ralstonia solanacearum and analysis of main components of essential oils by GC-MS.The results showed that the two kinds of oils had antimicrobial activity to JS 10726.The following 50%concentration of Zanthorylum bungeanum oil and following 10%Zanthoxylum schinifolium oil had no obvious antagonistic activity against JS 10726.There was no significant difference between 50%and 25%concentration of Zanthoxylum schinifolium oil on antimicrobial activity to JS 10726.The minimum inhibitory concentration(MIC)against R.solanacearum of Zanthoxylum schinifolium oils was 4%-6%,The minimum inhibitory concentration(MIC)of Zanthorylum bungeanum oils was over 10%.Zanthoxylum schifoliunm oil contained 25 kinds of components and main components included D-Limonene,ocimene,myrcene and linalool and that accounted for 70.56%its total components.Zanthorylum bungeanum oil contained 37 kinds of components and main components included linalool,D-Limonene and sabinene and that accounted for 86.23%its total components.2.Test the evaluation of their biocontrol effect towards bacterial wilt and growth promoting effect of Chinese Prickly Ash essential oils on tomatoIn this study,sprayed different concentrations of Chinese Prickly Ash essential oils on tomato leaves,then studied biocontrol effect towards Ralstonia solanacearum and tested the growth promoting effect of two kinds of oils on tomato.It showed that,after treating with essential oils,it could effectively delay the onset time of bacterial wilt on tomato.The onset time of bacterial wilt was delayed 5 days and 3 days after treated with 4%concentration of Zanthoxylum schinifolium oil and Zanthorylurm bungeanurm oil;20 days later,biocontrol effect reached 61.4%and 36.85%after treating with 4%concentration of Zanthoxylum schinifolium oil and Zanthorylulm bungeanum oil.After 15 days treating with Zanthorylum bungeanum oil,vane number of tomato was significantly more than the control;Root length had no significantly increase than the control,but shoot length was significantly thicker than the control after treating with two kinds of oils;After treating with 4%concentration of two kinds of oils,upside dry and fresh weight were significantly heavier than the control;After treating with 2%and 4%concentration of two kinds of oils,root dry and fresh weight were significantly heavier than the control.3.The mechanism of biocontrol effect towards tomato bacterial wilt by Chinese Prickly Ash essential oilsWe checked the changes of volatile components in the leaves and stems of tomato after spraying with Chinese Prickly Ash essential oils.At the same time,we tested defence genes that including PR1?PIN2?ERF1 related to salicylic acid,jasmonic acid,ethylene and Pti4 that was a tomato transcription factor.We investigated the the mechanism of biocontrol effect towards Ralstonia solanacearum by Chinese Prickly Ash essential oils preliminarily.The results showed that the monoterpenes were main components in the leaves and stems of tomato that including gamma.-Terpinene,Cyclohexene,beta.-Myrcene,beta.-Ocimene,alpha.-Phellandrene,Pinene,3-Carene,(E)-2-Hexenal and 2-Hexenal.The kinds of components in tomato leaves and stems were significantly more than that in control before and after inoculation and the contents of terpenoid were significantly increased than control.The contents of 3-Carene,(E)-2-Hexenal and gamma.-Terpinene in tomato of treatment groups were significantly higher than that of the control before inoculation.After inoculating with R.solanacearum,the kinds of components in tomato of treatment groups and control were all increased.The results of the expression of defense related gene showed that Chinese Prickly Ash essential oils main induced the expression of defense genes PR1 and PIN2 in tomato,while no significant changes in the expression of the key genes Pti4 and ERF1 related to ethylene signal pathway.4.InclusionThe research mainly focused on the study of improving the resistance to bacterial wilt disease on tomato and promoting tomato growth by Zanthorylum bungeanum oil and Zanthoxylum schinifolium oil.The results showed that the two kinds of essential oils had a good control effect on bacterial wilt of tomato and had certain promoting effect that would be a theoretical basis in agricultural with essential oils. |
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