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Association of a quantitative trait locus with growth of F. circinatum

Benedicta Swalarsk-Parry: Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria

<div><em>Fusarium circinatum</em> is an important pathogen of pine globally. Taxonomically,<em> F. circinatum</em> resides in the <em>Fusarium fujikuroi </em>species complex (FFSC), where it has been reported to hybridize with its close relative <em>Fusarium temperatum</em>. The F<sub>1</sub> progeny from the hybridization allowed for the construction of a genetic linkage map. The genomes of the two parental species have also been determined. In this study we used these available resources to detect and characterize a quantitative trait locus (QTL) associated with growth on malt extract agar medium supplemented with pine extract. The growth rate of the two parental isolates was significantly different (<em>P</em> < 0.05), with the majority of the F<sub>1</sub> progeny having significantly higher growth rate than the average growth of the two parents. The detected QTL was localised to a region on the <em>F. temperatum</em> genome, which contained two genes encoding a SUR7/RIM9-like membrane protein and a FAD-binding domain protein. This entire region was absent in the genome of the <em>F. circinatum</em> parent. Low G+C content, repetitive sequences and putative transposable elements were characteristic of this region in <em>F. circinatum</em> (FSP34). To further understand the role of the presence or absence of these genes in the FFSC, future work will focus on gene knockouts and complementation studies.</div>