Rice allelopathy and its properties of molecular ecology

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.