title: Induction of systemic resistance in rice by leaf extracts of Zizyphus jujuba and Ipomoea carnea against Rhizoctonia solani.
abstract: Plants accumulate a great diversity of natural products, many of which confer protective effects against phytopathogenic attack. Earlier we had demonstrated that the leaf extracts of Zizyphus jujuba and Ipomoea carnea inhibit the in vitro mycelial growth of Rhizoctonia solani, and effectively reduce the incidence of sheath blight disease in rice. Here we demonstrate that foliar application of the aqueous leaf extracts of Z. jujuba and I. carnea followed by challenge inoculation with R. solani induces systemic resistance in rice as evident from significantly increased accumulation of pathogenesis-related proteins such as chitinase, β-1,3-glucanase and peroxidase, as well as defense-related compounds such as phenylalanine ammonia-lyase and phenolic substances. Thin layer chromatographic separation of secondary metabolites revealed presence of alkaloid and terpenoid compounds in the leaf extracts of Z. jujuba that exhibited toxicity against R. solani under in vitro condition. Thus, the enhanced sheath blight resistance in rice seedlings treated with leaf extracts of Z. jujuba or I. carnea can be attributed to the direct inhibitory effects of these leaf extracts as well as their ability to elicit systemic resistance against R. solani.
authors: Centre for Plant Protection Studies, Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu, India. kagale.sateesh@gmail.com
authors: Sateesh
authors: S
authors: Kagale
authors: Thambiayya
authors: T
authors: Marimuthu
authors: Jayashree
authors: J
authors: Kagale
authors: Balsamy
authors: B
authors: Thayumanavan
authors: Ramasamy
authors: R
authors: Samiyappan
references: Plant Dis. 2000 Mar;84(3):341-356
references: 30841253
references: Phytopathology. 1998 Apr;88(4):359-65
references: 18944960
references: Mol Plant Microbe Interact. 1997 Sep;10(7):861-71
references: 9304860
references: Proc Natl Acad Sci U S A. 1988 Feb;85(3):782-6
references: 16578829
references: Plant Physiol Biochem. 2009 Sep;47(9):827-37
references: 19447634
references: Nature. 2001 Jun 14;411(6839):843-7
references: 11459067
references: Plant Dis. 2010 Aug;94(8):986-992
references: 30743492
references: Plant Cell. 1994 Sep;6(9):1191-1192
references: 12244269
references: Plant Cell. 1992 Jun;4(6):645-56
references: 1392589
references: Planta. 1983 Feb;157(1):22-31
references: 24263941
references: J Agric Food Chem. 2008 Oct 8;56(19):9236-45
references: 18788710
references: N Biotechnol. 2009 Dec 31;26(6):307-13
references: 19703599
references: Fitoterapia. 2001 Jun;72(5):507-10
references: 11429244
references: Ann Bot. 2002 May;89(5):503-12
references: 12099523
references: Indian J Exp Biol. 2001 Jun;39(6):600-3
references: 12562026
references: Planta Med. 2003 Nov;69(11):1051-4
references: 14735446
references: Food Chem Toxicol. 2009 Sep;47(9):2374-80
references: 19563858
references: J Agric Food Chem. 2003 Aug 13;51(17):4995-5000
references: 12903959
references: Plant Physiol. 1997 Mar;113(3):719-727
references: 12223638