Does Lr34 Enhance Leaf Rust Resistance In Wheat Seedlings?.

Recently, the wheat disease resistance gene Lr34 was cloned.  Lr34 is a putative ABC transporter and provides non-specific, adult plant resistance to Puccinia triticina Eriks.  (Krattinger et al, 2009. Science 323:1360).   There is strong evidence that Lr34 enhances single resistance gene effects in wheat seedlings, and now that Lr34 has been cloned, this can be verified genetically.  A cross between the isogenic wheat lines Thatcher Lr16 X Thatcher Lr16,34 was made, and 98 F2:6 near isogenic lines were evaluated for their response to Race 1 (BBBDB) of P. triticina in both seedlings and adult plants.  Lines were scored for the presence or absence of Lr34 enhancement in seedlings and evaluated for adult plant resistance and leaf tip necrosis.  Lr16 only lines had infection types of 2C while Lr16,34 lines had infection types of  ;, 1.  There are three known alleles of Lr34 and polymerase chain reaction primers are available for each.  PCR reactions on the 98 NILs are in process, and the results will be presented.