三七根腐病原菌毁坏柱孢霉分子定量检测方法及其应用

Molecular quantification of Cylindrocarpon destructans in the rhizosphere of Panax notoginseng for predicting plant growth response

摘要:

【目的】建立一种快速准确的三七根腐病病原真菌毁坏柱孢霉(Cylindrocarpon destructans)的分子定量检测方法，探讨毁坏柱孢霉与植株生长和AM真菌侵染之间的数量效应关系。【方法】根据GenBank登录的毁坏柱孢霉rDNA基因IGS序列片段，设计特异性引物对CDU2和CDL2b，利用含有SYBR Green I的实时荧光定量PCR建立毁坏柱孢霉定量检测方法，检测三七根际土壤毁坏柱孢霉rDNA基因IGS片段拷贝数，并分析其与植株生物量和AM真菌侵染之间的关系。【结果】发病植株根际土壤毁坏柱孢霉rDNA基因IGS片段拷贝数显著高于健康植株。三七根际土壤中毁坏柱孢霉数量与植株地上部生物量以及菌根侵染强度呈显著负相关(P＜0.05)，与根系生物量以及根内丛枝丰度相关性不显著。【结论】基于实时定量PCR技术建立的毁坏柱孢霉的分子定量方法能够有效反映三七根际土壤中毁坏柱孢霉的数量及其与植株生长和AM真菌侵染的关系。

Abstract:

[Objective] To establish a fast and accurate quantification method for Cylindrocarpon destructans causing root rot disease in the rhizosphere of Panax notoginseng, and to reveal the correlation of C. destructans abundance with plant growth and AM fungal colonization. [Methods] Based on the rDNA IGS sequence of C. destructans obtained from GenBank, specific primer pair CDU2 and CDL2b was designed. Molecular quantification of C. destructans by real-time PCR with SYBR Green I was established. IGS fragment copies of C. destructans in the rhizosphere of Panax notoginseng in field was detected with the newly established method and its relationships with plant biomass and AM fungal colonization were statistically analyzed. [Results] C. destructans was more abundant in rhizosphere of infected P. notoginseng than that of healthy plants (P<0.05). IGS fragment copies of C. destructans was negatively correlated with shoot biomass and mycorrhizal colonization rate, but the correlation between IGS fragment copies of C. destructans and root biomass and arbuscule abundance were insignificant. [Conclusion] The quantification method for C. destructans based on real-time PCR could well reflect the population dynamics of C. destructans in the rhizosphere of P. notoginseng in relation to plant growth and AM fungal colonization.