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Leaves serve as the major photosynthetic organs of plants and show considerable diversity in their shapes. Although significant efforts have been focused on exploring the molecular mechanism of leaf development, factors that are responsible for the lobed leaf formation remain unclear. A natural mutant named BM7 in melon ( Cucumis melo L.) that consists of palmately lobed leaf offers a unique opportunity to study the underlying mechanism of the lobed leaf shape formation. BM7 spontaneously arose from the melon line Mhy, which has normal round leaf, and was found in a field in China. Genetic analysis showed that the palmately lobed leaf trait was controlled by a single recessive gene, designated pll. Two BC populations derived from the cross of (Y8×BM7)×BM7 and (Jiashi×BM7)×BM7 were used to map pll by bulk segregant analysis using simple sequence repeat (SSR) markers. The pll gene was located on linkage group III of melon between SSR markers G69 and 784RS, and the physical distance is 14,631 bp according to the melon genome database. Only one gene, MELO3C010784, was predicted in this region. Gene MELO3C010784 is similar to the AP2-like ethylene-responsive transcription factor ANT, which plays a general role in maintaining meristematic competence in plants. This study is first report of its kind in mapping a gene that confers melon leaf trait and lays the foundation for investigations into the molecular mechanism of palmately lobed leaf formation in melon. [ABSTRACT FROM AUTHOR]

Powdery mildew is one of the most important melon pathogens all over the world. So far, many genes conferring resistance to powdery mildew of melon have been described, but few of these have been finely mapped or cloned. Two F populations derived from Ano2 × Hami413 and Ano2 × Queen were used to map the powdery mildew resistance gene by methods of Bulked Segregation Analysis (BSA), comparative genomics and Resistance Gene Analogues (RGA) mapping. It was found that the resistance to powdery mildew in Ano2 was conferred by a dominant gene, and the gene was named Pm- AN. The genetic analysis revealed that Pm- AN located between two codominant markers RPW and MRGH63B in linkage groupV. The genetic distances between Pm- AN and these two markers were 1.4-1.8 and 1.6-2 cM. No recombination was found between Pm- AN and markers ME/E1, SRAP23. Pm- AN was located in a RGA-rich region and cosegregated with the RGA marker MRGH5 and the resistance gene Vat. Synteny analysis showed that markers in this region were collinear between melon and cucumber. Segregation distortion was found in this region using both Ano2 × Hami413 and Ano2 × Queen F populations, and the distortion was more distinct in Ano2 × Hami413 F population. The center of segregation distortion was located in the RGA rich region harboring Pm- AN. [ABSTRACT FROM AUTHOR]