AUTHOR=Richa Kamboj , Tiwari Ila M. , Kumari Mandeep , Devanna B. N. , Sonah Humira , Kumari Archana , Nagar Ramawatar , Sharma Vinay , Botella Jose R. , Sharma Tilak R. 

TITLE=Functional Characterization of Novel Chitinase Genes Present in the Sheath Blight Resistance QTL: qSBR11-1 in Rice Line Tetep

JOURNAL=Frontiers in Plant Science

VOLUME=7

YEAR=2016

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2016.00244

DOI=10.3389/fpls.2016.00244

ISSN=1664-462X

ABSTRACT=<p>Rice sheath blight disease caused by <italic>Rhizoctonia solani</italic> 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 <italic>R. solani</italic> has been reported. In this study, we have performed molecular and functional analysis of the genes associated with the major <italic>R. solani</italic>-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 <italic>R. solani</italic> 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 <italic>in vitro</italic> for six of the eleven genes showed chitinolytic activity in gel assays but we did not detect any xylanase inhibitory activity. All the six <italic>in vitro</italic> expressed proteins show antifungal activity with a clear inhibitory effect on the growth of the <italic>R. solani</italic> mycelium. The characterized chitinase genes can provide an important resource for the genetic improvement of <italic>R. solani</italic> susceptible rice lines for sheath blight resistance breeding.</p>