外源CPPU调控薇甘菊开花及保护酶基因表达的研究

Regulation of flowering and protective enzyme gene expression in Mikania micrantha by exogenous hormone CPPU

【目的】薇甘菊是Ⅰ级外来入侵有害植物,依靠种子进行快速蔓延传播,造成了重大生态和经济损失。通过探明N-(2-氯-4-吡啶基)-N-苯基脲(CPPU)对薇甘菊繁殖调控的机理,为遏制薇甘菊快速扩散的趋势提供一种新的策略。【方法】本研究计数CPPU处理后薇甘菊花序和小花的数量,利用RNA-seq分析CPPU抑制薇甘菊成花的机理,并测定薇甘菊开花期保护酶的酶活性。【结果】(1)CPPU能够抑制薇甘菊成花,随着处理浓度的升高,薇甘菊花序和小花的数量均呈下降趋势,其中,5 mg/L CPPU处理后的薇甘菊花序数减少了34.50%,小花数减少了36.70%;75 mg/L CPPU处理后无花。(2)转录组分析揭示了保护酶基因的差异表达,75 mg/L的CPPU处理后,大量与POD和PAL相关的差异基因(DEGs)上调表达。(3)保护酶酶活性测试结果表明:CPPU处理降低了苯丙氨酸解氨酶(PAL)、过氧化物酶(POD)和过氧化氢酶(CAT)的酶活性,但提高了多酚氧化酶(PPO)的酶活性。【结论】75 mg/L的CPPU能通过调控薇甘菊保护酶基因的表达,造成膜脂过氧化伤害,抑制薇甘菊成花,从而有效控制薇甘菊的繁殖与传播。

[Objective]Mikania micrantha is a class I alien invasive harmful plant,which relies on seeds to spread rapidly,causing significant ecological and economic losses.By exploring the mechanism of N-(2-chloro-4-pyridyl)-N-phenylurea(CPPU)on the reproductive regulation of M.micrantha,a new strategy was provided to curb the trend of M.micrantha’s rapid spread.[Method]The number of inflorescences and florets of M.micrantha treated with CPPU was counted anatomically.The mechanism of inhibition of flowering by CPPU was analyzed by RNA-seq,and determined the enzyme activities of protective enzymes in flowering stage of M.micrantha.[Result](1)CPPU could effectively inhibit the flower formation of M.micrantha,with the increase of CPPU concentration,the number of inflorescences and florets decreased.After being treated with 5 mg/L CPPU,the number of inflorescences and florets decreased by 34.50%and 36.70%,respectively.There was no flower after 75 mg/L of CPPU treatment.(2)Transcriptome analysis revealed differential regulation of protective enzyme genes,it was found that,after being treated with 75 mg/l CPPU,a large number of DEGs related to pod and PAL were up-regulated;(3)the results of the protective enzyme activity indicated that CPPU treatment decreased the enzyme activity of PAL(phenylalanine ammonia-lyase),POD(peroxidase)and CAT(catalase),but increased the protective enzyme activity of PPO(polyphen oloxidase tyrosinase phenlase).[Conclusion]75 mg/L of CPPU can control the expression of protective enzyme gene of M.micrantha,which cause membrane lipid peroxidation damage and inhibit the flowering process,thus it can effectively control the reproduction and spread of M.micrantha.