Submitted to: Rice Technical Working Group Meeting Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 2/29/2004
Publication Date: 2/1/2005
Citation: Singh, P., Jia, Y., Eizenga, G.C., Lee, F. 2005. Cloning and characterization of induced genes by the sheath blight pathogen rhizoctonia solani. Rice Technical Working Group Meeting Proceedings. Abstract p. 114.
Technical Abstract: Sheath blight caused by Rhizoctonia solani Kühn is a serious disease in rice growing areas worldwide. No complete genetic source of resistance is known among rice cultivars. A rice cultivar, Jasmine 85 has shown considerable resistance to sheath blight that appears to be controlled by several minor resistance genes. The objective of the present study is to clone these minor resistance genes for stacking them into improved rice cultivars. To clone these candidate resistance gene(s), a subtractive cDNA library was constructed using Jasmine 85 inoculated with a virulent field isolate of R. solani. For this purpose, inoculation experiments were conducted using detached leaf inoculation method and 16 hours after inoculation was selected for isolating differentially expressed genes. Total RNAs from inoculated and control leaf samples were isolated by RNeasy Plant Mini protocol. A PCR-based method was used for producing high-quality cDNA from the total RNA by Super SMARTTM PCR cDNA synthesis kit. These cDNAs obtained from inoculated and control samples were used for PCR-Select cDNA subtraction protocol according to the manufacturer's recommendations. The PCR mixture enriched for differentially expressed cDNAs was cloned in TOPO TA cloning vector and sequenced using ABI-PRISM BigDyeTM Terminator Cycle Sequencing. So far, 133 expressed sequence tags have been identified. Most of the genes are unrelated with the disease resistance but few of them are potential candidates for sheath blight control. These promising candidate genes are a putative protein kinase, a putative wall-associated kinase, a putative K+/H+ antiporter, PDR-and MDR-like ABC transporters. Research to confirm the expression of these genes is in progress. These genes will eventually be used to develop user-friendly DNA markers for developing a complete resistance to sheath blight.