|Miklas, Phillip - Phil|
Submitted to: Bean Improvement Cooperative Annual Report
Publication Type: Abstract Only
Publication Acceptance Date: 3/17/2008
Publication Date: 4/26/2008
Citation: Miklas, P.N., Seo, Y.S., Gilbertson, R. 2008. The bct-1 locus for resistance to beet curly top virus is associated with quantitative resistance to bean dwarf mosaic virus in common bean. Bean Improvement Cooperative Annual Report. 51:92-93.
Technical Abstract: Host resistance provides effective control of some diseases induced by geminiviruses in common bean. A recessive gene bgm-1 conditions resistance to Bean golden yellow mosaic virus (BGYMV) and is located on linkage group B3 near the bc-12 gene for resistance to Bean common mosaic virus. The dominant Bct-1 gene conditions resistance to Beet curly top virus (BCTV) and is located on linkage group B7 in the vicinity of a QTL for resistance to BGYMV. These genomic associations of host resistances to different geminiviruses, and between a geminivirus and a potyvirus as in the first example, suggest presence of individual resistance genes with broad effect against multiple virus species and/or presence of resistance gene clusters formed from gene duplication events with subsequent divergence for specific resistance against different viruses. We sought to examine the effect of the Bct gene that conditions resistance to BCTV (curtovirus) against another distinct geminivirus, Bean dwarf mosaic virus (BDMV), a begomovirus. Uniform disease reaction for the parents was observed. Moncayo with resistance to BCTV had complete resistance to BDMV, and Primo susceptible to BCTV was completely susceptible to BDMV. The F1 population was resistant to BDMV indicating dominant inheritance. The RILs expressed a quantitative disease reaction to BDMV. The RILs with Bct-1 had plants with a DSI mostly rated 1 or 2 for BDMV reaction with a mean DSI of 1.42. RILs without Bct-1 had plants mostly rated 3 and 4 for BDMV with a mean of 3.07. Generally, RILs scoring <2.0 for BDMV reaction also possessed BCTV resistance, and RILs scoring > 2.0 were susceptible to BCTV. Six RILs had a weak association between BDMV and BCTV reactions. Bct-1 explains 69.6% of the phenotypic variation for reaction to BDMV based on single factor ANOVA. In summary, Bct-1 or a closely linked gene confers quantitative resistance to BDMV. This quantitative resistance to BDMV is different from the qualitative resistance conferred by the Bdm gene. The genomic location of Bdm is unknown. Resistance to BCTV, BDMV, and BGYMV is associated on linkage group B7.