Phylogeography of maize landraces from Northern Argentina: insights from chloroplast genomes

LÓPEZ MG; PUEBLA A.; FASS M.; VERA P.; PANIEGO N.; HOPP HE; LIA VV

Foz de Iguazu

Congreso; 11th International Plant Molecular Biology Congress; 2015

Native maize landraces are valuable reservoirs of original alleles for crop improvement. In Argentina these resources are maintained by traditional farmers, who descended from indigenous populations. Nowadays, local landraces are threatened by the mixing with commercial material and the replacement of native varieties by more productive crops. Knowledge of the levels and distribution patterns of genetic variation in traditional landraces is essential in order to make proper decisions for conservation and to develop successful protection programs. Previous studies have detected significant genetic structuring between maize landraces from North West (NWA) and East (NEA) Argentina using microsatellite markers. However, additional information is still needed to clarify the origin of the Argentinean native germplasm and establish the focus of future conservation efforts. In the present study, we used whole chloroplast genome sequences to analyze the observed patterns of variation within a phylogeographic framework. Chloroplast genomes from a set of maize landraces from NWA and NEA were amplified with long-PCR protocols, subsequently sequenced with Illumina MiSeq technologies and assembled using the B73 inbred line sequence as reference. Twenty nine di-allelic SNP loci were identified. Little to no variation was observed among NEA landraces, whose chloroplast genome sequences were identical to that of the B73 inbred line in most individuals. Haplotypes from Andean landraces (NWA) were different from those of NEA at all the detected SNPs and differed at 15 SNP when compared to the A188 cultivar. These results support previous hypotheses that propose two separate routes of maize diffusion into South America.