Comparative analysis on metabolites and gene expression difference of various allelopathic potential rice under weed stress

Abstract

AbstractIn this study, allelopathic rice ‘PI312777’ (PI) and non‐allelopathic rice ‘Lemont’ (LE) were used to study gene expression related to secondary metabolism and relative metabolites in soil under field conditions with and without weeding. The results showed that the inhibition rates of PI and LE soils to barnyard grass were significantly increased under weed stress. The inhibition rate of phenolic acid extracts in PI rhizosphere soils was significantly higher (p < 0.05) without the weeding treatment than with the weeding treatment; however, it was not significantly different in LE rhizosphere soils. There were no significant differences in the inhibition rates of other soil extracts (terpenoids, alkaloids and fatty acids) of PI and LE in treatments with and without weeding. Under weed stress, six genes (PAL, C4H, F5H, COMT, CCR and CAD) related to phenolic acid metabolism were upregulated in the leaves and roots of PI, while only four of the six genes were upregulated and two genes were downregulated in LE. The genes related to terpenoid metabolism (seven genes), alkaloid metabolism (three genes) and fatty acid metabolism (two genes) were upregulated in the roots and leaves of PI and LE under weed stress, but the differences were not significant. These results suggest that the increase in phenolic acids in the presence of weeds under field conditions contributed the majority of the inhibition effect in rice allelopathy.