Rhizobium-mediated induction of phenolics and plant growth promotion in rice (Oryza sativa L.).
Qualitative and quantitative estimation of phenolic compounds was done through reverse phase-high performance liquid chromatography (RP-HPLC) from different parts (leaf, stem, and root) of rice plants after inoculation with two rhizobial strains, RRE6 (Rhizobium leguminosarum bv. phaseoli) and ANU 843 (R. leguminosarum bv. trifolii) and infection by Rhizoctonia solani. On the basis of their retention time, the major phenolic acids detected in HPLC analysis were gallic, tannic, ferulic, and cinnamic acids. Furthermore, in all Rhizobium-inoculated rice plants, synthesis of phenolic compounds was more consistently enhanced than in control (uninoculated plants), where the maximum accumulation of phenolic compounds was observed in plants inoculated with RRE6 and infection with R. solani. Under pathogenic stress, RRE6 performed better because a relatively higher amount of phenolics was induced as compared with plants treated with ANU 843. Phenolic acids mediate induced systemic resistance and provide bioprotection to plants during pathogenic stresses. In addition, both rhizobial strains promote growth and productivity of rice plants in greenhouse conditions. This report on Rhizobium-mediated defense responses and growth promotion of nonlegume (such as rice) provides a novel paradigm of symbiotic plant-microbe interaction.
Mishra
Ravi P N
RP
Microbial Genetics Laboratory, Department of Genetics and Plant Breeding, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi, 221 005, India. ravi_bhu05@yahoo.com
Singh
Ramesh K
RK
Jaiswal
Hemant K
HK
Kumar
Vinod
V
Maurya
Sudarshan
S
D062385:Hydroxybenzoates / Q000378:metabolism*; D012275:Oryza / Q000254:growth & development* / Q000378:metabolism / Q000382:microbiology*; D018515:Plant Leaves / Q000378:metabolism / Q000382:microbiology; D018517:Plant Roots / Q000378:metabolism / Q000382:microbiology; D018547:Plant Stems / Q000378:metabolism / Q000382:microbiology; D016961:Rhizobium leguminosarum / Q000254:growth & development*; D042161:Rhizobium phaseoli / Q000254:growth & development*; D013559:Symbiosis
D062385:Hydroxybenzoates; C017616:phenolic acid