乙氧氟草醚对桂味荔枝冬梢控杀效果及内源激素影响的研究

Study on Oxyfluorfen Control Effect of Oxyfluorfen on Guiwei Litchi Winter Shoots(Litchi chinensis Sonn.)and Its Influence on Endogenous Hormones

为了探究二苯醚类除草剂乙氧氟草醚在抑制荔枝(Litchi chinensis Sonn.)冬梢生长中的应用效果及其杀梢机理,以水处理为对照,设计并比较分析了不同浓度乙氧氟草醚对桂味荔枝冬梢的抑制效果。并利用植物组织切片、台盼蓝染色、转录组学、串联质谱和实时荧光定量PCR(qRT-PCR)等方法对试验材料进行检测分析。结果表明,综合比较处理时间和控杀效果,80μmol·L^(-1)乙氧氟草醚是桂味荔枝控冬梢的最佳浓度。乙氧氟草醚对荔枝冬梢具有抑制作用,但对于无伤口的成熟叶片没有明显的伤害性。冬梢(20 h水处理对照和80μmol·L^(-1)乙氧氟草醚处理)的比较转录组学结果显示,显著差异基因主要富集在植物信号转导、植物与病原菌互作和丝裂原活化蛋白激酶(MAPK)信号途径等代谢通路。与对照相比,乙氧氟草醚诱导冬梢中茉莉酸类、水杨酸类和乙烯前体1-氨基环丙烷羧酸(ACC)含量升高;乙烯信号途径6个关键基因、茉莉酸途径6个关键基因和水杨酸途径3个关键基因共15个基因在冬梢(水处理对照和乙氧氟草醚处理)中的相对表达量在处理10 h时变化不显著,在处理20 h时较10 h激增。本研究为二苯醚类除草剂控制荔枝冬梢的有效性和安全性,以及通过调节胁迫相关内源激素含量及代谢通路继而诱导荔枝冬梢细胞凋亡的机制研究提供了参考依据。

In order to investigate effect of different application rates and the shoot killing mechanism of diphenyl ether herbicidal oxyfluorfen,the inhibitory effects of different concentrations of the herbicide on winter shoots of Guiwei lychee were studied using plant tissue sections,trypan blue staining,liquid chromatograph mass spectrometer/mass spectrometer,transcriptome,and quantitative real-time polymerase chain reaction techniques.The results revealed that the optimal concentration of oxyfluorfen for suppressing lychee winter shoots was 80 mol·L^(-1).Oxyfluorfen inhibited lychee winter shoots but had no impact on mature leaves with no wounds.The comparative transcriptome results of water control and 80 mol·L^(-1)oxyfluorfen applied to winter shoot samples at 20 h revealed that the significantly different genes were mainly enriched in metabolic pathways such as plant signal transduction,plant pathogen interaction,and the mitogen-activated protein kinase signal pathway.The levels of six endogenous hormones and precursors in the control and treated samples revealed that the contents of jasmonic acid,salicylic acid,and the ethylene precursor 1-aminocyclopropane-1-carboxylate increased following ethoxyflurane compared with water treatment.In winter shoots treated with 80 mol·L^(-1)of oxyfluorfen,the relative expression levels of six important genes in the ethylene signaling system,six key genes in the jasmonic acid pathway,and three essential genes in the salicylic acid pathway were increased.This study established a reference basis for further investigation on the effectiveness and safety of diphenyl ether herbicides in reducing lychee winter shoots,as well as the molecular mechanisms of producing lychee winter shoot cell death and changes in endogenous hormone levels.