Obstacles in Continuous Chinese Medicinal Herbs Production and Plant Allelopathy.

Obstacles in Continuous Chinese Medicinal Herbs Production and Plant allelopathy

Wenxiong Lin^1,2*

1.        Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring (School of Life Sciences, Fujian Agriculture and Forestry University), Fuzhou 35002, People's Republic of China

2.     Key Laboratory of Crop Ecology and Molecular Physiology(Fujian Agriculture and Forestry University), Fujian Province University, Fuzhou 35002, People's Republic of China

Abstract: As the in-depth study of rhizosphere ecology, the researches on plant allelopathy and consecutive monoculture problem gradually focus on rhizospheric biological processes. The cross-talk between plants and microbes is the key factor for plant allelopathy and consecutive monoculture problem. Consecutive monoculture problem, also known as allelopathic autotoxicity, was shown as serious soil disease in plants, consequently resulting in decreased biomass and quality under consecutive monoculture. Recent researches have displayed that the ecological effects of soil microbial functional disorder mediated by root exudates were the main reasons for the consecutive monoculture problems of Chinese medicinal herbs. The results from metagenomics combined with qRT-PCR showed the increase in F. oxysporum and a reduction in abundance of Pseudomonas sp., especially the Pseudomonas sp. with the antagonistic activity against F. oxysporuman in consecutively monocultured soils as compared to control and newly planted soils. Furthermore, we found that the phenolic compounds mixture at their proportions detected in the soil significantly promoted the mycelial growth, spore and toxin production of pathogenic F. oxysporum, but showed a great inhibitory effect on the growth of beneficial Pseudomonas. These findings suggested that the restoration and improvement of disease-conducive soil environment was crucial to the remediation of unbalanced microbial community structure, and increase of ecosystem functions to overcome the problems. On the other hand, our researches showed that the phenolic compounds released by the roots of allelopathic rice could greatly promote the growth of host-specific myxobacteria. Together with the phenolics, these myxobacteria are able to inhibit the germination and growth of target barnyard grass. Amensalism has been widely applied in weed control, and great achievements have been made in the practice. In conclusion, plant-plant interactions are the results of the comprehensive effect of the rhizospheric talk between plants and microbes. The deep understanding of plant-soil-microbe interactions mediated by root exudates has important meaning for elucidating the functions of rhizosphere microecology and providing practice guidelines in agriculture production.

Keywords: Allelopathy, autotoxicity, medicinal plant, rice, rhizospheric biology, soil microbes

 E-mail:wenxiong181@163.com.

This work was supported by the National Natural Science Foundation of China (No. U1205021, 31271670), National Basic Research Program of China (973 Program, No. 2012CB126309) and 948 Project of Chinese Ministry of Agriculture (2014-Z36)