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

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.

Key words:Panax notoginseng, Root rot disease, Cylindrocarpon destructans, Real-time PCR, AM fungi