| 【Objective】The differences of six kinds of endogenous hormone contents between the diseased and asymptomatic branches and leaves of Trema levigata Hand.-Mazz. witches' broom disease induced by phytoplasma were determined, which laid a foundation for the research of pathogenesis of T. levigata Hand.-Mazz. witches' broom disease and provided theoretical basis for the prevention and treatment of this disease.【Methods】The infected samples with typical symptoms of witches' broom and healthy samples with normal morphology were collected from the same plant in the
field of Xinping County, Yunnan Province. Liquid chromatography-tandem mass spectrometry（LC-MS/MS）was used to qualitatively and quantitatively detect the contents of 25 types of plant hormones in six categories（auxin, cytokinin, abscisic acid, jasmonic acid, salicylic acid and gibberellin）.【Results】A total of 24 hormones were detected, H2JA was not detected in both infected and healthy samples, cZ was not detected in infected samples, GA19 was only detected in infected samples, and GA20, GA24 and GA53 were only detected in healthy samples. The content of MESA was the highest, there were highly significant differences in contents of IAA, IBA, ICA, MEJA, JA, JA-ILE, MESA, SA and ABA, and significant
differences in those of IP and tZ between infected samples and healthy samples. The contents of GA3, GA19, GA20, GA7, GA9 and GA15 in gibberellin changed greatly. The content of six kinds of plant hormones in infected samples decreased significantly and the C/A ratio increased.【Conclusion】The study showed that the contents of plant endogenous hormones in phytoplasma-infected tissues of T. levigata Hand.-Mazz witches' broom changed significantly. The main symptom of this phytoplasma disease was the witches' broom, which was often caused by the comprehensive influence of various pathogenic factors. Further studies were needed to determine which hormone imbalance was the main causative factor. |
