Rice allelopathy and its properties of molecular ecology

Abstract

Crop allelopathy is a promising and environmentally friendly method in weed control; however, the inducible genetic trait for allelopathy in the suppression of weeds needs to be overcome for practical use. Further study needs to be directed to this end to elucidate the molecular genetics and its physiologic mechanism. In this paper, the authors review recent advances in the investigation of rice allelopathy and its molecular regulatory mechanism, especially in responses to stressful conditions including biotic and abiotic factors in China. Previous studies show that rice allelopathy could be enhanced when the rice accession was exposed to stressful conditions, and further analysis by the transcriptomics and proteomics approaches conducted in our laboratory indicated that the increase in allelopathic potential of rice, when exposed to the stresses, was attributed to increased expression level of genes involved in phenolic synthetic metabolism. The increasing phenolic compounds have been confirmed as the main allelochemicals and they jointly act to suppress the target, especially in responses to stressful condition, but it seems to be the primary effect in phenolic allelopathy. We still wonder how the exudates from rice root, which were released into rhizosphere soil, are transformed by soil microorganism to produce the higher secondary effect of phenolic allelopathy in the suppression of weeds. Therefore, the authors suggest that rhizosphere biologic properties of allelopathy in rice and its mechanism are being the key research areas in the world now, and systems biology and its approaches, such as metagenomics and metaproteomics, would be helpful to reveal the process and its molecular ecological mechanism regarding rhizospheric biology of rice allelopathy.

Crop Performance and Weed Suppression by Weed-Suppressive Rice Cultivars in Furrow- and Flood-Irrigated Systems under Reduced Herbicide Inputs

“…Nutrient stress conditions are common in lowinput agriculture, and ''low-N'' stress has been associated with enhanced allelopathic activity of PI 312777, which was accompanied by activation of genes involved in synthesis of allelochemicals (Fang et al 2010;Song et al 2008). Lin et al (2010) reported that under low-N stress, increased allelopathic potential was associated with increased expression of genes involved in phenolic biosynthesis. Thus, this trait could contribute to the potential suitability of PI 312777 and similar germplasm lines for low-input systems.…”

Mixed Phenolic Acids Mediated Proliferation of Pathogens Talaromyces helicus and Kosakonia sacchari in Continuously Monocultured Radix pseudostellariae Rhizosphere Soil

“…Phenolic acids are important in allelopathy and replanting disease incidence (Bais et al, 2004 ; Kulmatiski et al, 2008 ; Wu et al, 2015 ; Zhao et al, 2015 ). Phenolic compounds are autotoxins of the plants in monocropping system, such as Rehmannia glutinosa , cucumber, and tobacco (Fang et al, 2010 , 2013 ; Lin et al, 2010 ; Li et al, 2012 ; Zhou and Wu, 2012b ; Wu et al, 2015 ). Some studies indicate that phenolic acids change the soil microbial community with possible influences on plant performance (Zhou et al, 2012 , 2014 ).…”

Integrated pest management for sustainable rice cultivation: a holistic approach

“…The search for allelopathic rice varieties and molecular approaches to improving rice competition with weeds, although not as prominent as research into other native traits, was topical between 2000 and 2010. More recently, allelopathy as a function of rhizosphere bacteria has gained increasing attention (Lin et al, 2010).…”