Changxun Fang. Pioneers of Allelopathy: Wenxiong Lin

Wenxiong Lin did research for > 30 years in plant molecular ecology and agro-ecology, rice allelopathy and continuous monoculture problems/soil sickness of Chinese medicinal plants. His 20 Patents and most publications (about 100) have focussed on (i). Gene regulation of allelochemicals biosynthesis in allelopathic rice, (ii). allelopathic inhibitory effects on weeds, (iii). continuous monoculture problems/soil sickness in medicinal plants and (iv). the influence of allelochemicals and monoculture practice on the rhizospheric micro-environment. He helped in development of microbial fertilizer to alleviate the autotoxicity problem in continuous cropping of Radix pseudostellariae and Rehmannia glutinosa, etc. He had been the President of Asian Allelopathy Society, and got the outstanding achievement from the platform of International Allelopathy Foundation. His student, Dr. Changxun Fang got Rice Award and Grodzinsky Award respectively in the 6th and 8th World Congress of International Allelopathy Society. His elucidation of the molecular ecological mechanism of rice allelopathy was awarded the II Class Prize of Fujian Provincial Scientific and Technological Progress Award in 2007. His researches to find the mechanism of development of continuous cropping obstacle/soil sickness in R. pseudostellariae and its remedy was awarded the I Class Prize of Fujian Provincial Scientific and Technological Progress Award in 2020.

Effect Study of Continuous Monoculture on the Quality of Salvia miltiorrhiza Bge Roots

High-efficiency monoculture severely inhibits the growth of Salvia miltiorrhiza Bge and decreases the yield and quality of crude drug, thus resulting in serious economic losses in China. Here, we selected four replanted field soils with 1, 2, 3, and 4 years of monoculture history to investigate the influence of continuous monocropping soil on the property of medicinal materials by pot experiments. Results showed that the commodity appearance and active ingredient contents of Salvia miltiorrhiza were significantly affected by soil with different continuous monocropping years. Along the time series of plantation soil, the diameter of main roots, weight of fresh roots, and total contents of hydrophilic and lipophilic components demonstrated a decline tendency. With the method of PCA, the property of medicinal materials affected by continuous monocropping soil was evaluated by the following formula: F=0.3762×F1+0.2320×F2+0.1913×F3+0.0994×F4/0.8989. Eventually, crude drug properties ranked according to comprehensive scores were as follows: CK 0.380>1 year 0.360>2 years 0.348>3 years 0.337>4 years 0.245. For the medicinal plant of Salvia miltiorrhiza Bge, continuous monocropping soil had significant effects on the property of Salvia miltiorrhiza and should be ameliorated by some measures. The results provide support for the optimal continuous cropping year selection and continuous cropping obstacle abatement of Salvia miltiorrhiza Bge.

Soil domestication by rice cultivation results in plant-soil feedback through shifts in soil microbiota

Background Soils are a key component of agricultural productivity, and soil microbiota determine the availability of many essential plant nutrients. Agricultural domestication of soils, that is, the conversion of previously uncultivated soils to a cultivated state, is frequently accompanied by intensive monoculture, especially in the developing world. However, there is limited understanding of how continuous cultivation alters the structure of prokaryotic soil microbiota after soil domestication, including to what extent crop plants impact soil microbiota composition, and how changes in microbiota composition arising from cultivation affect crop performance. Results We show here that continuous monoculture (> 8 growing seasons) of the major food crop rice under flooded conditions is associated with a pronounced shift in soil bacterial and archaeal microbiota structure towards a more consistent composition, thereby domesticating microbiota of previously uncultivated sites. Aside from the potential effects of agricultural cultivation practices, we provide evidence that rice plants themselves are important drivers of the domestication process, acting through selective enrichment of specific taxa, including methanogenic archaea, in their rhizosphere that differ from those of native plants growing in the same environment. Furthermore, we find that microbiota from soils domesticated by rice cultivation contribute to plant-soil feedback, by imparting a negative effect on rice seedling vigor. Conclusions Soil domestication through continuous monoculture cultivation of rice results in compositional changes in the soil microbiota, which are in part driven by the rice plants. The consequences include a negative impact on plant performance and increases in greenhouse gas emitting microbes.

Continuous Monoculture Shapes Root and Rhizosphere Fungal Communities of Corn and Soybean in Soybean Cyst Nematode-Infested Soil

The rhizosphere effect shapes microbial communities around and within plant roots and may lead to the enrichment of fungi involved in both positive and negative plant-soil feedbacks. We used internal transcribed spacer 1 amplicon sequencing to investigate how continuous monoculture affects the fungal communities in the corn and soybean rhizosphere, rhizoplane, and root endosphere in a long-term crop rotation experiment where soils were infested with a major soybean pathogen, the soybean cyst nematode (SCN, Heterodera glycines). Community-level statistical analyses showed evidence of selective filtering and enrichment of fungi in and around corn and soybean roots and in SCN cysts. Patterns of relatedness between fungal communities in various agroecosystem compartments suggested that SCN cysts are colonized by soybean root endophytic fungi and that colonization of roots and cysts may aid proliferation of these fungi in the bulk soil agroecosystem compartment over time. Natural antagonists of the SCN such as nematode-trapping fungi and nematode endoparasites increased in relative abundance in the rhizosphere and root endosphere, respectively, over continuous soybean monoculture. In contrast, arbuscular mycorrhizal and plant-pathogenic fungi, several of which were negatively correlated with corn yield, increased in relative abundance over continuous corn monoculture. These results suggest the possibility of positive plant-soil feedbacks involving nematophagous fungi over continuous soybean monoculture and negative plant-soil feedbacks involving plant pathogens and some nonbeneficial arbuscular mycorrhizal fungi over continuous corn monoculture.