Citrullus lanatus (watermelon) is an excellent daily source of dietary lycopene and β-carotene. To investigate the transcriptional regulation of carotenoid biosynthesis genes relative to lycopene and β-carotene accumulation in watermelon fruit, six watermelon accessions with different flesh colors were examined in this study: white-fleshed PI 459074, pale-yellow-fleshed ‘Cream of Saskatchewan’, light-pink-fleshed PI 482255, orange-yellow-fleshed ‘WM-Clr-1’, and red-fleshed ‘LSW177’ and ‘MSW28’. The expression patterns of eight genes (PSY1, PSY2, PDS, ZDS, CRTISO, LCYB, NCED1, and NCED7) involved in lycopene and β-carotene biosynthesis and biodegradation were analyzed. The results confirmed the accumulation of large quantities of lycopene in red-fleshed ‘LSW177’ and ‘MSW28’, reflecting the elevated expression of PSY1 and the low transcriptional expression of NCED1. The relative expression levels of NCED1 likely play an important role in the color development of the light-pink-fleshed PI 482255, whereas the reduced transcriptional expression of PSY1 and the increased expression of NCED1 appear to be the main factors contributing to the formation of white flesh in the fruit of PI 459074. Low transcriptional expression of PSY1 results in the pale-yellow flesh of the ‘Cream of Saskatchewan’ fruit.
Nan Wang, Shi Liu, Peng Gao, Feishi Luan and Angela R. Davis
Taifeng Zhang, Jiajun Liu, Shi Liu, Zhuo Ding, Feishi Luan and Peng Gao
Short internode length (SIL) is one of the most commercially and important traits in melon varieties (Cucumis melo L.). SIL can result in a compact vining type that promotes concentrated fruit in high-density crops, leading to greater use of light resources for photosynthesis and greater yield per unit area. In our study, two parental melon lines ‘M1-32’ (P1, standard vine) and ‘X090’ (P2, short internodes), and their F1, F2, BC1P1, and BC1P2 progenies were evaluated after being grown in plastic greenhouse conditions in 2017 and 2018. Main stem length (MSL) and internode length (IL) of six melon generations indicated that a single recessive gene (MD7) controlled dwarfism in the ‘X090’ melon line. Whole-genome analysis revealed a genomic region harboring the candidate dwarfism gene on chromosome 7. Six polymorphic cleaved amplified polymorphic sequence (CAPS) markers from chromosome 7 were used to construct a genetic linkage that spanned 30.28 cM. The melon dwarfing locus MD7 responsible for SIL was positioned between markers M7-4 and M7-5, with 3.16 cM of flanking distance. The CAPS markers M7-4 and M7-5 developed have the potential to accelerate the development of dwarf melon varieties, especially in situations when dwarf genotypes are an important breeding goal using marker-assisted selection.
Bin Cai, Cheng-Hui Li, Ai-Sheng Xiong, Ri-He Peng, Jun Zhou, Feng Gao, Zhen Zhang and Quan-Hong Yao
The database of grape transcription factors (DGTF) is a plant transcription factor (TF) database comprehensively collecting and annotating grape (Vitis L.) TF. The DGTF contains 1423 putative grape TF in 57 families. These TF were identified from the predicted wine grape (Vitis vinifera L.) proteins from the grape genome sequencing project by means of a domain search. The DGTF provides detailed annotations for individual members of each TF family, including sequence feature, domain architecture, expression information, and orthologs in other plants. Cross-links to other public databases make its annotations more extensive. In addition, some other transcriptional regulators were also included in the DGTF. It contains 202 transcriptional regulators in 10 families.