title: Comparative Transcriptome Analysis of Cultivated and Wild Watermelon during Fruit Development.
abstract: Watermelon [Citrullus lanatus (Thunb.) Matsum. & Nakai] is an important vegetable crop world-wide. Watermelon fruit quality is a complex trait determined by various factors such as sugar content, flesh color and flesh texture. Fruit quality and developmental process of cultivated and wild watermelon are highly different. To systematically understand the molecular basis of these differences, we compared transcriptome profiles of fruit tissues of cultivated watermelon 97103 and wild watermelon PI296341-FR. We identified 2,452, 826 and 322 differentially expressed genes in cultivated flesh, cultivated mesocarp and wild flesh, respectively, during fruit development. Gene ontology enrichment analysis of these genes indicated that biological processes and metabolic pathways related to fruit quality such as sweetness and flavor were significantly changed only in the flesh of 97103 during fruit development, while those related to abiotic stress response were changed mainly in the flesh of PI296341-FR. Our comparative transcriptome profiling analysis identified critical genes potentially involved in controlling fruit quality traits including α-galactosidase, invertase, UDP-galactose/glucose pyrophosphorylase and sugar transporter genes involved in the determination of fruit sugar content, phytoene synthase, β-carotene hydroxylase, 9-cis-epoxycarotenoid dioxygenase and carotenoid cleavage dioxygenase genes involved in carotenoid metabolism, and 4-coumarate:coenzyme A ligase, cellulose synthase, pectinesterase, pectinesterase inhibitor, polygalacturonase inhibitor and α-mannosidase genes involved in the regulation of flesh texture. In addition, we found that genes in the ethylene biosynthesis and signaling pathway including ACC oxidase, ethylene receptor and ethylene responsive factor showed highly ripening-associated expression patterns, indicating a possible role of ethylene in fruit development and ripening of watermelon, a non-climacteric fruit. Our analysis provides novel insights into watermelon fruit quality and ripening biology. Furthermore, the comparative expression profile data we developed provides a valuable resource to accelerate functional studies in watermelon and facilitate watermelon crop improvement.
authors.affiliation: Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, Department of Vegetable Science, College of Agronomy and Biotechnology, China Agricultural University, Beijing, China; Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (North China), National Engineering Research Center for Vegetables, Beijing, China.
authors.forename: Shaogui
authors.initials: S
authors.lastname: Guo
authors.affiliation: Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (North China), National Engineering Research Center for Vegetables, Beijing, China; Boyce Thompson Institute for Plant Research, Cornell University, Ithaca, NY, United States of America.
authors.forename: Honghe
authors.initials: H
authors.lastname: Sun
authors.affiliation: Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (North China), National Engineering Research Center for Vegetables, Beijing, China.
authors.forename: Haiying
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (North China), National Engineering Research Center for Vegetables, Beijing, China.
authors.forename: Jingan
authors.initials: J
authors.lastname: Liu
authors.affiliation: Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (North China), National Engineering Research Center for Vegetables, Beijing, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Ren
authors.affiliation: Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (North China), National Engineering Research Center for Vegetables, Beijing, China.
authors.forename: Guoyi
authors.initials: G
authors.lastname: Gong
authors.affiliation: Boyce Thompson Institute for Plant Research, Cornell University, Ithaca, NY, United States of America.
authors.forename: Chen
authors.initials: C
authors.lastname: Jiao
authors.affiliation: Boyce Thompson Institute for Plant Research, Cornell University, Ithaca, NY, United States of America.
authors.forename: Yi
authors.initials: Y
authors.lastname: Zheng
authors.affiliation: Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, Department of Vegetable Science, College of Agronomy and Biotechnology, China Agricultural University, Beijing, China.
authors.forename: Wencai
authors.initials: W
authors.lastname: Yang
authors.affiliation: Boyce Thompson Institute for Plant Research, Cornell University, Ithaca, NY, United States of America; USDA Robert W. Holley Center for Agriculture and Health, Ithaca, NY, United States of America.
authors.forename: Zhangjun
authors.initials: Z
authors.lastname: Fei
authors.affiliation: Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (North China), National Engineering Research Center for Vegetables, Beijing, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Xu
mesh_terms: D050260:Carbohydrate Metabolism / Q000235:genetics; D002338:Carotenoids / Q000096:biosynthesis / Q000378:metabolism; D029773:Citrullus / Q000166:cytology / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development*; D005030:Ethylenes / Q000096:biosynthesis / Q000378:metabolism; D005638:Fruit / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development*; D020869:Gene Expression Profiling; D015398:Signal Transduction / Q000235:genetics
chemical_list: D005030:Ethylenes; D002338:Carotenoids; C036216:ethylene