植物生长调节剂与杀菌剂互作防治棉花枯萎病及增效作用探究

Interaction Between Plant Growth Regulator and Fungicide to Control Cotton Fusarium wilt and the Synergy Mechanism

本实验旨在筛选出能有效防治棉花枯萎病的植物生长调节剂与杀菌剂组合,并探究其增效机理,为植物生长调节剂与杀菌剂互作防治棉花枯萎病提供技术指导和理论依据。通过室内毒力测定挑选EC_(50)最小的2种杀菌剂;通过种子活力和分生孢子萌发实验确定植物生长调节剂的最适浓度;两者混用进行室内盆栽试验,测定两者互作的防治效果及增效作用;通过q RT-PCR测定茉莉酸(jasmonic acid,JA)和水杨酸(salicylic acid,SA)途径相关基因在棉花中的表达量。试验结果发现,5种杀菌剂中多菌灵和萎锈灵的EC_(50)最小,对枯萎病菌的毒力最强,EC_(50)分别为13.894 mg/L和29.566 mg/L;综合苄氨基嘌呤和萘乙酸2种植物生长调节剂对种子活力的影响和对枯萎病菌分生孢子萌发的影响,得到其最适防治浓度分别为5 mg/L和50 mg/L。杀菌剂与植物生长调节剂互作防治棉花枯萎病效果最好的为苄氨基嘌呤与多菌灵组合,防效可达80.95%,且具有显著增效作用;qRT-PCR结果显示,JA和SA途径相关基因在药剂处理的棉花中的相对表达显著增加。综上所述,植物生长调节剂与杀菌剂互作中苄氨基嘌呤与多菌灵组合可对棉花枯萎病进行有效防治,其可通过诱导棉花启动自身的JA和SA防御途径增强对棉花枯萎病的防治效果。

We designed this study to explore the combination of plant growth regulator and fungicide,which could benefit the cotton resistance to Fusarium wilt.Moreover,the synergy mechanism of the combination was investigated,to provide insights into enhancing cotton resistance to Fusarium wilt.Through indoor toxicity test,two fungicides with the minimum EC_(50)were selected.The most suitable plant growth regulators were also identified by seed vigor testing and conidial germination statistic of Fusarium wilt.The combination of fungicide and plant growth regulator was applied during the plant growth in greenhouse to evaluate the synergy effect.To explore the mechanism underlying the combination of fungicide and plant growth regulator,we detected the expression levels of genes involving in jasmonic acid-related and salicylic acid-related pathways by qRT-PCR.The results of fungicide selection showed that carbendazim and carboxin had the minimum EC_(50)and the strongest virulence to Fusarium wilt,the EC_(50)was 13.894 mg/L and 29.566 mg/L,respectively.Plant growth regulator selection indicated that the optimal concentration 6-Benzylaminopurine and naphthylacetic acid was 5 mg/L and 50 mg/L,respectively.Finally,the most suitable combination was 6-Benzylaminopurinecarbendazim,which had the control effect of 80.95%and significant synergy effect.The results of qRT-PCR also showed that genes in jasmonic acid-related and salicylic acid-related pathways had significantly higher expression levels in the treated group than those in blank control group.In conclusion,the 6-Benzylaminopurine-carbendazim combination could enhance the cotton resistance to Fusarium wilt by activating transcription of genes in jasmonic acid-related and salicylic acid-related pathways.