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

Abstract

To explore the molecular mechanism of allelopathic rice in response to low nitrogen (N) supply or accompanying weed stress, allelopathic rice PI 312777 and its counterpart Lemont were grown under low N supply or co-cultured with barnyardgrass [Echinochloa crus-galli (L.) Beauv.] in hydroponics. The suppression subtractive hybridization (SSH) technique was employed to isolate the up-regulated genes in the treated rice accession. The results indicated that the expression of the genes associated with N utilization was significantly up-regulated in allelopathic rice PI 312777, and the higher efficiency of N uptake and its utilization were also detected in PI 312777 than that in Lemont when the two rice accessions were exposed to low N supply. This result suggested that the allelopathic rice had higher ability to adapt to low N stress than its nonallelopathic counterpart. However, a different response was observed when the allelopathic rice was exposed to accompanying weed (barnyardgrass) co-cultured in full Hoagland solution (normal N supply). It showed that the expression of the genes associated with allelochemical synthesis and its detoxification were all up-regulated in the allelopathic rice when co-cultured with the target weed under normal N supply. The results suggested that the allelopathic rice should be a better competitor in the riceweed co-culture system, which could be attributed to increasing de novo biosynthesis and detoxification of allelochemicals in rice, consequently resulting in enhanced allelopathic effect on the target and preventing the autotoxicity in this process. These findings suggested that the accompanying weed, barnyardgrass is not only the stressful factor, but also one of the triggers in activating allelopathy in rice. This implies that the allelopathic rice is sensible of the existing target in chemical communication.

Effects of low nitrogen and drought stresses on proline synthesis of Jatropha curcas seedling

“…Low nitrogen supply suppressed the biosynthesis of protein, nucleic acid, and other metabolites, eventually resulting in low biomass and leaf area. Several studies have demonstrated that the nitrogen starvation-stress and low-nitrogen stress could induce genes expression in plants (Chen et al 2003;Fang et al 2010). The level of P5CS could also be regulated by the nitrogen supply Kishor et al 1995).…”

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 ).…”

Transcriptome analysis reveals that barnyard grass exudates increase the allelopathic potential of allelopathic and non-allelopathic rice (Oryza sativa) accessions

“…These results indicated that the allelopathic rice accession PI responds more actively than the non-allelopathic rice accession LE to root exudates treatment. Previously reported morphological, physiological, and biochemical results indicated that PI is more sensitive than LE under various biotic and abiotic stresses (Shin et al 2000; He et al 2008; Fang et al 2010; Wang et al 2010; Kato-Noguchi 2011; He et al 2012). We suggest that this result derives from the genetic traits of the allelopathic rice accessions.…”

“…However, three decades after Dilday’s study, rice allelopathy has yet to be widely applied in practice. The main reason is that rice allelopathy is a quantitative trait that is heavily influenced by environmental conditions (Dilday et al 2000; Shin et al 2000; Fang et al 2010; Kato-Noguchi 2011; Wang et al 2010; He et al 2012). Rice allelopathic activity is polygenically controlled (Ebana et al 2001; Jensen et al 2001, 2008; He et al 2004; Junaedi et al 2007).…”

“…However, the high allelopathic activity of wild types may be reduced or lost in crops during hybridization and selection for other characteristics (Putnam and Duke 1974; Dilday et al 2000). Studies have shown that abiotic stress, such as nitrogen (N), phosphorous (P), and potassium (K) deficiency (He et al 2008; Wang et al 2010; Fang et al 2010) and UV-B irradiation (Shin et al 2000), and biotic stress, such as the co-cultivation of rice and barnyard grass (Kato-Noguchi 2011; He et al 2012), could enhance the allelopathic potential of allelopathic rice accessions. Recent studies show that allelopathy can be induced by exogenous application of chemicals, such as exogenous phenolic acids, methyl jasmonate, and methyl salicylate (Kong et al 2004a; Bi et al 2007; Fang et al 2009; Xu et al 2010; Kato-Noguchi 2011).…”