COMAV, Instituto de Conservación y Mejora de la Agrodiversidad, Universitat Politècnica de València, Cno. de Vera, s/n, 46022 València, Spain.
IHSM La Mayora, CSIC-UMA, Avda. Dr. Wienberg s/n, 29750 Málaga, Spain.
Int J Mol Sci. 2022 Oct 19;23(20):12553. doi: 10.3390/ijms232012553.
Cucurbits powdery mildew (CPM) is one of the main limiting factors of melon cultivation worldwide. Resistance to races 1, 2, and 5 has been reported in the African accession TGR-1551, whose resistance is controlled by a dominant-recessive epistasis. The dominant and recessive quantitative trail loci (QTL) have previously been located in chromosomes 5 and 12, respectively. We used several densely genotyped BC families derived from the cross between TGR-1551 and the susceptible cultivar 'Bola de Oro' to finely map these resistance regions. The further phenotyping and genotyping of the selected BC, BCS, BCS, BCS, BCxPS, and (BCxPS) S offspring allowed for the narrowing of the candidate intervals to a 250 and 381 kb region in chromosomes 5 and 12, respectively. Moreover, the temperature effect over the resistance provided by the dominant gene has been confirmed. High resolution melting markers (HRM) were tightly linked to both resistance regions and will be useful in marker-assisted selection programs. Candidate R genes with variants between parents that caused a potential modifier impact on the protein function were identified within both intervals. These candidate genes provide targets for future functional analyses to better understand the resistance to powdery mildew in melons.
瓜类白粉病（CPM）是全球甜瓜种植的主要限制因素之一。在非洲登录号 TGR-1551 中已经报道了对 1、2 和 5 号菌系的抗性，其抗性由显性-隐性上位性控制。先前已经将显性和隐性数量性状位点（QTL）分别定位在第 5 和第 12 号染色体上。我们使用了几个来自 TGR-1551 和易感品种'Bola de Oro'之间杂交的密集基因型 BC 家系，以精细地定位这些抗性区域。对选定的 BC、BCS、BCS、BCS、BCxPS 和 (BCxPS) S 后代进行进一步表型和基因型分析，将候选区间分别缩小到第 5 和第 12 号染色体上的 250 和 381 kb 区域。此外，还证实了显性基因提供的抗性对温度的影响。与两个抗性区域紧密连锁的高分辨率熔解标记（HRM）将在标记辅助选择计划中非常有用。在这两个区间内都鉴定到了候选 R 基因，这些基因在父母之间存在变体，可能对蛋白质功能产生修饰影响。这些候选基因提供了未来功能分析的目标，以更好地了解甜瓜对白粉病的抗性。
