Flowering time is a complex trait important for crop adaptation to local environments and an essential breeding target to face the challenge of global climate change. A major quantitative trait locus (QTL) for flowering time and number of nodes (ND), qVgt3.05 (Vgt3), was previously identified on chromosome 3, bin 3.05, in a maize introgression library (IL) derived from the cross B73 x Gaspé Flint (recipient and donor genotypes, respectively. Salvi et al. 2011). In order to clone Vgt3, B73 was crossed with its early isogenic line 39-1-2-33 which carries a 17-cM Gaspé Flint introgression on bin 3.05. Using this cross, Vgt3 showed an addictive effect of 1.4 nodes, explained 56.6% of the phenotypic variance and was mapped within 0.3 cM. For positional cloning, a total of 7,500 F2 plants were phenotyped and genotyped with SNPs and SSR markers flanking the QTL interval. One-hundred recombinants lines were derived and the QTL was further narrowed the target genomic region to a 380-kb interval. A MADS-box gene with no coding sequence variation between the two alleles was found in the physical interval. However, the MADS-box gene RNA expression profile and transgenics testing confirmed its effect on flowering time. We are currently searching for the Vgt3 causative regulatory region by studying chromosome structural variation between the B73 and Gaspé Flint alleles.
Cloning of Vgt3, a major QTL for flowering time in maize
EMANUELLI, FRANCESCO;ZAMARIOLA, LINDA;GIULIANI, SILVIA;BOVINA, RICCARDO;ORMANBEKOVA, DANARA;TUBEROSA, ROBERTO;SALVI, SILVIO
2017
Abstract
Flowering time is a complex trait important for crop adaptation to local environments and an essential breeding target to face the challenge of global climate change. A major quantitative trait locus (QTL) for flowering time and number of nodes (ND), qVgt3.05 (Vgt3), was previously identified on chromosome 3, bin 3.05, in a maize introgression library (IL) derived from the cross B73 x Gaspé Flint (recipient and donor genotypes, respectively. Salvi et al. 2011). In order to clone Vgt3, B73 was crossed with its early isogenic line 39-1-2-33 which carries a 17-cM Gaspé Flint introgression on bin 3.05. Using this cross, Vgt3 showed an addictive effect of 1.4 nodes, explained 56.6% of the phenotypic variance and was mapped within 0.3 cM. For positional cloning, a total of 7,500 F2 plants were phenotyped and genotyped with SNPs and SSR markers flanking the QTL interval. One-hundred recombinants lines were derived and the QTL was further narrowed the target genomic region to a 380-kb interval. A MADS-box gene with no coding sequence variation between the two alleles was found in the physical interval. However, the MADS-box gene RNA expression profile and transgenics testing confirmed its effect on flowering time. We are currently searching for the Vgt3 causative regulatory region by studying chromosome structural variation between the B73 and Gaspé Flint alleles.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
