title: Functional Characterization of Novel Chitinase Genes Present in the Sheath Blight Resistance QTL: qSBR11-1 in Rice Line Tetep.
abstract: Rice sheath blight disease caused by Rhizoctonia solani is one of the most devastating diseases in rice leading to heavy yield losses. Due to the polygenic nature of resistance, no major resistance gene with complete host resistance against R. solani has been reported. In this study, we have performed molecular and functional analysis of the genes associated with the major R. solani-resistance QTL qSBR11-1 in the indica rice line Tetep. Sequence analysis revealed the presence of a set of 11 tandem repeats containing genes with a high degree of homology to class III chitinase defense response genes. Real-time quantitative PCR analysis showed that all the genes are strongly induced 36 h after R. solani infection. Comparison between the resistant Tetep and the susceptible HP2216 lines shows that the induction of the chitinase genes is much higher in the Tetep line. Recombinant protein produced in vitro for six of the eleven genes showed chitinolytic activity in gel assays but we did not detect any xylanase inhibitory activity. All the six in vitro expressed proteins show antifungal activity with a clear inhibitory effect on the growth of the R. solani mycelium. The characterized chitinase genes can provide an important resource for the genetic improvement of R. solani susceptible rice lines for sheath blight resistance breeding.
authors.affiliation: ICAR-National Research Centre on Plant BiotechnologyNew Delhi, India; Department of Bioscience and BiotechnologyBanasthali Vidyapith, Vanasthali, India.
authors.forename: Kamboj
authors.initials: K
authors.lastname: Richa
authors.affiliation: ICAR-National Research Centre on Plant Biotechnology New Delhi, India.
authors.forename: Ila M
authors.initials: IM
authors.lastname: Tiwari
authors.affiliation: ICAR-National Research Centre on Plant Biotechnology New Delhi, India.
authors.forename: Mandeep
authors.initials: M
authors.lastname: Kumari
authors.affiliation: ICAR-National Research Centre on Plant Biotechnology New Delhi, India.
authors.forename: B N
authors.initials: BN
authors.lastname: Devanna
authors.affiliation: ICAR-National Research Centre on Plant Biotechnology New Delhi, India.
authors.forename: Humira
authors.initials: H
authors.lastname: Sonah
authors.affiliation: ICAR-National Research Centre on Plant Biotechnology New Delhi, India.
authors.forename: Archana
authors.initials: A
authors.lastname: Kumari
authors.affiliation: ICAR-National Research Centre on Plant Biotechnology New Delhi, India.
authors.forename: Ramawatar
authors.initials: R
authors.lastname: Nagar
authors.affiliation: Department of Bioscience and Biotechnology Banasthali Vidyapith, Vanasthali, India.
authors.forename: Vinay
authors.initials: V
authors.lastname: Sharma
authors.affiliation: School of Agriculture and Food Sciences, The University of Queensland Brisbane, QLD, Australia.
authors.forename: Jose R
authors.initials: JR
authors.lastname: Botella
authors.affiliation: ICAR-National Research Centre on Plant Biotechnology New Delhi, India.
authors.forename: Tilak R
authors.initials: TR
authors.lastname: Sharma
keywords: Rhizoctonia solani; Tetep; chitinase; sheath blight; xylanase