Growth promoting and antagonistic effects of endophytic fungus Aspergillus sydowii from Paris polyphylla var. chinensis

Abstract:

[Background] Paris polyphylla var. chinensis is a kind of precious chinese medicine materials. Over-exploitation leads to the lack of wild resources. The artificial cultivation is restricted by the poor growth and frequent occurrence of diseases. [Objective] Exploring of plant probiotics is an effective and environment friendly solution, according to the requirements of ecological planting. [Methods] Endophytic fungus was isolated by conventional methods and identified by comprehensive methods. The germination test of maize seeds was carried out for screening the isolated fungus which had been reported to promote growth and resist disease. The nitrogen fixation activity of microorganism was tested qualitatively by nitrogen-free ager. Antimicrobial activity was detected by plate antagonism test. High performance liquid chromatography-mass spectrometry (LC-MS) were used to detected the metabolic components of microorganism and the contents of salicylic acid, jasmonic acid, abscisic acid, gibberellins, cytokinins, auxins in leaves. The underground biomass indexes were also measured. [Results] One of fungi was identified as Aspergillus sydowii by rDNA ITS sequencing, morphological observation, physiological and biochemistry identification, named jdqmzz-1. The strain jdqmzz-1 which contains kinds of stimulative, antibacterial, and insecticidal substances can promote the growth of Paris polyphylla var. chinensis, fix nitrogen, and antagonize pathogenic microorganism. The antagonistic index was 42.50%. The Paris polyphylla var. chinensis seedlings endogenous gibberellins and auxins in leaves were increased by 54.1 and 2.3 times, chlorophyll contents were increased by 48.80%, malondialdehyde contents were decreased by 15.20%, respectively, while treating with the strain. Average root numbers, root lengths and hundred plant weights of seedlings were also significantly increased. [Conclusion] The isolated endophytic fungus Aspergillus sydowii strain jdqmzz-1 can effectively promote the growth of Paris polyphylla var. chinensis.