A Phylogenetic Analysis of the African Plant Genus Palisota (family Commelinaceae) based on Chloroplast DNA Sequences

The plant genus Palisota (family Commelinaceae, or spiderwort family) consists of approximately 20 species and is distributed throughout the forests of tropical Africa. The genus exhibits several unusual morphological characteristics, and as a result has been difficult to classify based on morphology. Molecular phylogenetic studies have placed it near the base of Commelinaceae, but the exact placement of Palisota within the family is not clear. As the African continent has become more arid in recent geological times, the forests have receded, reducing the habitat for Palisota species and potentially impacting speciation and extinction rates within the genus. The goal of this study is to sequence the chloroplast-encoded gene rbcL in several additional species of Palisota and its relatives in order to: 1) determine the phylogenetic relationship of the genus with respect to other members of Commelinaceae; 2) evaluate phylogenentic relationships among species of Palisota; and 3) infer relative speciation/extinction rates within the genus. Additionally, we are exploring the use of other molecular regions for phylogenetic analysis with the genus

Genome-Wide Association Study of Anthracnose Resistance in Andean Beans (Phaseolus vulgaris).

Anthracnose is a seed-borne disease of common bean (Phaseolus vulgaris L.) caused by the fungus Colletotrichum lindemuthianum, and the pathogen is cosmopolitan in distribution. The objectives of this study were to identify new sources of anthracnose resistance in a diverse panel of 230 Andean beans comprised of multiple seed types and market classes from the Americas, Africa, and Europe, and explore the genetic basis of this resistance using genome-wide association mapping analysis (GWAS). Twenty-eight of the 230 lines tested were resistant to six out of the eight races screened, but only one cultivar Uyole98 was resistant to all eight races (7, 39, 55, 65, 73, 109, 2047, and 3481) included in the study. Outputs from the GWAS indicated major quantitative trait loci (QTL) for resistance on chromosomes, Pv01, Pv02, and Pv04 and two minor QTL on Pv10 and Pv11. Candidate genes associated with the significant SNPs were detected on all five chromosomes. An independent QTL study was conducted to confirm the physical location of the Co-1 locus identified on Pv01 in an F4:6 recombinant inbred line (RIL) population. Resistance was determined to be conditioned by the single dominant gene Co-1 that mapped between 50.16 and 50.30 Mb on Pv01, and an InDel marker (NDSU_IND_1_50.2219) tightly linked to the gene was developed. The information reported will provide breeders with new and diverse sources of resistance and genomic regions to target in the development of anthracnose resistance in Andean beans

Chromosome, position, p-value, proportion of phenotypic variation explained (R²) and minor allele frequency of the two most significant SNPs for seven races of anthracnose resistance measured on 226 Andean bean genotypes.

<p>Chromosome, position, p-value, proportion of phenotypic variation explained (R²) and minor allele frequency of the two most significant SNPs for seven races of anthracnose resistance measured on 226 Andean bean genotypes.</p

QQ and Manhattan Plots showing candidate SNPs and P-values from GWAS using MLM for anthracnose resistance.

<p>From top to bottom include results for anthracnose resistance to A) race 65, B) race 73, and C) race 3481 on Pv01. Red line on Manhattan Plots is the significance threshold of P = 1.03 x 10⁻⁵ after Bonferonni correction of α = 0.05.</p

Phenotypic and genotypic reaction to screening RIL parents, differentials, cultivars and advanced breeding lines to anthracnose race 73 and InDel Marker NDSU_IND_1_50.2219.

<p>Phenotypic and genotypic reaction to screening RIL parents, differentials, cultivars and advanced breeding lines to anthracnose race 73 and InDel Marker NDSU_IND_1_50.2219.</p