Analysis of gene expressions associated with increased allelopathy in rice (Oryza sativa L.) induced by exogenous salicylic acid

Abstract

The defense characteristics of allelopathic rice accession PI312777 and its counterpart Lemont induced by exogenous salicylic acid (SA) to suppress troublesome weed barnyardgrass (BYG) were investigated using the methods of suppression subtractive hybridization (SSH) and real-time fluorescence quantitative PCR (qRT-PCR). The results showed that exogenous SA could induce the allelopathic effect of rice on BYG and this inducible defense was SA doserespondent and treatment time-dependent. PI312777 exhibited higher inhibitory effect than Lemont on BYG after treated with different concentrations of SA. The activities of cell protective enzymes including SOD, POD and CAT in the BYG plants co-cultured with PI312777 treated by SA were highly depressed compared with the control (co-cultured with rice without SA-treatment). Similar but lower depression on these enzymes except for CAT was also observed in the BYG plants when co-cultured with Lemont treated by SA. It is therefore suggested that allelopathic rice should be more sensitive than non-allelopathic rice to exogenous SA. Seventeen genes induced by SA were obtained by SSH analysis from PI312777. These genes encode receptor-kinase proteins, ubiquitin carrier proteins, proteins related to phenylpropanoid metabolism, antioxidant related proteins and some growth-mediating proteins. The differential expressions of these genes were validated in part by qRT-PCR in the two rice accessions. Our work elucidated that allelopathic rice possesses an active chemical defense and auto-detoxifying enzyme system such as the up-regulated enzymes involved in de novo biosynthesis of phenolic allelochemicals and the glutathione-S-transferase (GST) associated with xenobiotic detoxification.

Genomic analysis of allelopathic response to low nitrogen and barnyardgrass competition in rice (Oryza sativa L.)

“…Allelopathy in crops, however, is considered as a complex phenomenon of chemical ecology, which can be regulated by temperature, illumination, soil condition, herbicides, exogenous hormones and especially nutrient levels in the growth environment (Einhellig 1999;Wu et al 1999;Belz 2007;Shen and Lin 2007;Song et al 2008;Bi et al 2007;Fang et al 2009b;Wang et al 2009). In a previous study, we found that rice cultivar PI 312777 exposed to limited nutrient conditions performed higher allelopathic effect on the accompanying barnyardgrass than that to normal nutrient conditions (Xiong et al 2005;Shen and Lin 2007;Song et al 2008;Wang et al 2009).…”

Effects of High Night Temperature on Crop Physiology and Productivity: Plant Growth Regulators Provide a Management Option

“…al., 1997;Diaz-Zorita et. al., 2001;Fang et al, 2009;Mohammed & Tarpley, 2009b). In rice, exogenous application of GB or SA increased total antioxidant capacity under high night temperature (Fig.…”

Positive allelopathic stimulation and underlying molecular mechanism of achyranthe under continuous monoculture

“…Suppression subtractive hybridization (Diatchenko et al 1996;Fang et al 2009) was employed to construct a subtractive library. Total RNA was extracted from the shoots of extract-treated achyranthes and its control using the Trizol method (Invitrogen).…”