Molecular tagging and genetic mapping of the disease resistance gene RppQ to southern corn rust

Abstract

Southern corn rust (SCR), Puccinia polysora Underw, is a destructive disease in maize ( Zea mays L.). Inbred line Qi319 is highly resistant to SCR. Results from the inoculation test and genetic analysis of SCR in five F(2) populations and five BC(1)F(1 )populations derived from resistant parent Qi319 clearly indicate that the resistance to SCR in Qi319 is controlled by a single dominant resistant gene, which was named RppQ. Simple sequence repeat (SSR) analysis was carried out in an F(2) population derived from the cross "Qi319x340". Twenty SSR primer pairs evenly distributed on chromosome10 were screened at first. Out of them, two primer pairs, phi118 and phi 041, showed linkage with SCR resistance. Based on this result, eight new SSR primer pairs surrounding the region of primers phi118 and phi 041 were selected and further tested regarding their linkage relation with RppQ. Results indicated that SSR markers umc1,318 and umc 2,018 were linked to RppQ with a genetic distance of 4.76 and 14.59 cM, respectively. On the other side of RppQ, beyond SSR markers phi 041 and phi118, another SSR marker umc1,293 was linked to RppQ with a genetic distance of 3.78 cM. Because the five linkage SSR markers (phi118, phi 041, umc1,318, umc 2,018 and umc1,293) are all located on chromosome 10, the RppQ gene should also be located on chromosome 10. In order to fine map the RppQ gene, AFLP (amplified fragment length polymorphism) analysis was carried out. A total 54 AFLP primer combinations were analyzed; one AFLP marker, AF1, from the amplification products of primer combination E-AGC/M-CAA, showed linkage with the RppQ gene in a genetic distance of 3.34 cM. Finally the RppQ gene was mapped on the short arm of chromosome 10 between SSR markers phi 041 and AFLP marker AF1 with a genetic distance of 2.45 and 3.34 cM respectively.

Identification of a Maize Locus That Modulates the Hypersensitive Defense Response, Using Mutant-Assisted Gene Identification and Characterization

“…We are also currently working to construct B73 near isogenic lines differing for Hrml1 We will further cross them to lines carrying other Rp1 alleles to confirm that this locus also modifies the wild-type Rp1-mediated response. It also remains to be determined whether Hrml1 modulates cell-death phenotypes conferred by other major, HRconferring, maize disease-resistance genes such as Rxo , other Rp genes (e.g., Webb et al 2002), and Rpp genes (Storey and Howland 1957;Futrell et al 1975;Chen et al 2004) and possibly also by non-HR causes of programmed cell death (Buckner et al 2000).…”

Construction and characterization of a bacterial artificial chromosome library of the maize inbred line Qi319

“…According to the results of previous studies (Chen et al 2004, Zhou et al 2007, primers linked to the genes for resistance to maize southern rust and rough dwarf disease were synthesized by Shanghai Shenggong Company (Shanghai, China). Primer phi041 belongs to the SSR marker, and MA7 is a SCAR marker converted from a RAPD fragment.…”

“…However, the genes that confer resistance to these maize diseases have not been cloned. The original studies on these genes mainly focused on inheritance regulation and mapping (Chen et al 2004, Jines et al 2007. Given the advantages of high cloning efficiency, good stability, easy preparation, and ease of manipulation, the bacterial artificial chromosome (BAC) cloning system is an invaluable tool for gene cloning and structural and functional analyses (He et al 2010).…”

Characterization and molecular mapping of RsrR, a resistant gene to maize head smut

“…Genomic DNA was extracted from young leaves of individual plant and dissolved in TE solution as our previous report (Chen et al 2004). DNA concentrations were estimated and adjusted to 200 ng/ll.…”

“…SSR analysis was performed as our previous report (Chen et al 2004). SSR products were separated on 3.0 % agarose gel stained with ethidium bromide (EB) or on 6 % poly-acrylamide gel electrophoresis (PAGE) sequencing gel stained by the rapid silver staining method (Xu et al 2002).…”