外源茉莉酸对三七根系代谢物的影响及关键代谢物诱导三七抗病性分析

Effects of exogenous jasmonic acid on the metabolites of Panax notoginseng(Burk.)F. H. Chen root system and the induction of disease resistance in Panax notoginseng(Burk.)F. H. Chen by key metabolites

  • 摘要: 【目的】揭示叶部喷施茉莉酸(Jasmonic acid,JA)诱导三七根系的代谢变化,明确显著变化的代谢物,为三七病害的生物防治提供理论基础。【方法】以三七为试验材料,在叶部接种黑斑病菌(Alternaria panax)菌株SL17,于接种4和8 d时测定三七植株内源JA含量;于三七叶片外源喷施不同浓度的JA后,利用气相色谱—质谱联用仪(GC-MS)分析三七根系代谢物变化,并检测显著变化代谢物对主要根腐病菌的抑制活性及其灌根后诱导三七叶部抗黑斑病的效果。【结果】叶部接种黑斑病菌4 d时,三七叶部JA和茉莉酸亮氨酸螯合物(JA-ile)的含量增加而在根系减少;接种8 d时,叶部JA含量显著增加(P<0.05,下同),而根系中2种物质的含量均极显著增加(P<0.01)。外源喷施不同浓度JA后三七根系代谢变化测定结果显示,三七根系中共检测出125种代谢物,主要分为有机酸类、氨基酸类、酯类、糖类、胺类、核苷酸及其衍生物和酮类等,其中有机酸类、氨基酸类和糖类是根系代谢物中的主要成分。与对照相比,叶部施用JA后三七根系中的草酸和氢化乳清酸含量显著增加。进一步测定显著变化的差异代谢物功能发现,草酸和氢化乳清酸对三七主要根腐病菌具有一定的抑制活性,其中氢化乳清酸在浓度为0.001 μg/mL时对茄腐镰刀菌(Fusarium solani)菌株F3和锈腐病菌(Ilyonectria destructans)菌株RS6的抑制效果最佳,浓度为0.010 μg/mL时对锈腐病菌菌株RS8的抑制效果最佳,浓度为0.100 μg/mL时对恶疫霉(Phytophthora cactorum)菌株D-6的抑制效果最佳;草酸浓度为0.001 μg/mL时对菌株F3的抑制效果最佳,浓度为10.000 μg/mL时对菌株D-6的抑制效果最佳;草酸和氢化乳清酸灌根后还能明显减小三七叶部黑斑病的病斑面积,且均在浓度10.000 μg/mL时诱导抗病效果最佳。【结论】外源喷施JA可改变三七根系代谢,促进氢化乳清酸和草酸的积累,进而增强三七对黑斑病的抗性,并对三七主要根腐病菌具有一定的抑制活性。

     

    Abstract: 【Objective】This study aimed to inresligate the metabolic changes of Panax notoginseng(Burk.)F. H. Chen root system induced by jasmonic acid(JA)spraying on leaves,and clarify the significantly changed metabolites, so as to provide a basis for biological control of P. notoginseng diseases.【Method】P. notoginseng was used as experiment materials. This study determined the content of endogenous hormone JA in P. notoginseng after inoculation on leaves with Alternaria panax strain SL17 for 4 and 8 d. Metabolic changes in P. notoginseng root system were analyzed by using gas chromatography-mass spectrometry(GC-MS)after exogenously spraying on leaves with different concentrations of JA. This study measured the effects of significantly changed metabolites on resistance against major root rot pathogens and the induction of black spot disease resistance in P. notoginseng after root irrigation.【Result】The content of JA and Jasmonic acid leucine chelate(JA-ile)in the leaves increased while the content of the both substances in the root system decreased after inoculation on leaves for 4 d. The content of JA in the leaves was significantly increased(P<0.05,the same below),and the contents of two substances in root system were extremely significantly increased(P<0.01)after inoculation for 8 d.After exogenously spraying different concentrations of JA, the metabolism change analysis of P. notoginseng root system showed that 125 metabolites were detected in the root system of P. notoginseng,mainly categorized as organic acids, amino acids, esters, sugars, amines, nucleotides and their derivatives and ketones, of which sugars, organic acids and amino acids were the main components. Compared with the blank control,the content of oxalic acid and dihydroorotic acid in the root system of P. notoginseng increased significantly after exogenously spraying JA on the leaves. Further study on significantly changed differential matebolities revealed that oxalic acid and dihydroorotic acid had certain inhibitory effect against the major root rot pathogens of P. notoginseng. Among them,dihydroorotic acid with the concentration of 0.001 μg/mL had the best inhibitory effect against Fusarium solani strain F3 and Ilyonectria destructans strain RS6. Dihydroorotic acid with the concentration of 0.010 μg/mL had the best inhibitory effect against I. destructans strain RS8. Dihydroorotic acid with the concentration of 0.100 μg/mL had the best inhibitory effect against Phytophthora cactorum strain D-6. Oxalic acid with the concentration of 0.001 μg/mL had the best inhibitory effect against F. solani strain F3. Oxalic acid with the concentration of 10.000 μg/mL had the best inhibitory effect against P. cactorum strain D-6. Oxalic acid and dihydroo-rotic acid significantly reduced the lesion area of black spot disease on leaves of P. notoginseng after root irrigation and represented the most induction of disease resistance in the concentration of 10.000 μg/mL.【Conclusion】Exogenously spraying JA can alter P. notoginseng root system metabolism and promote the accumulation of dihydroorotic acid and oxalic acid,which enhance plant resistance against black spot disease and show inhibitory effect against main root rot pathogens.

     

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