title: The Cytochrome P450 GeneCsCYP85A1Is a Putative Candidate forSuper Compact-1(Scp-1) Plant Architecture Mutation in Cucumber (Cucumis sativusL.).
abstract: The dwarf or compact plant architecture is an important trait in plant breeding. A number of genes controlling plant height have been cloned and functionally characterized which often involve in biosynthesis or signaling of plant hormones such as brassinosteroids (BRs). No genes for plant height or vine length have been cloned in cucurbit crops (familyCucurbitaceae). From an EMS-induced mutagenesis population, we identified asuper compact(SCP) mutant C257 which was extremely dwarf due to practically no internode elongation. Under dark growing condition, C257 did not undergo skotomorphogenesis and its mutant phenotype could be rescued with exogenous application of brassinolide (BL), suggesting SCP might be a BR-deficient mutant. Segregation analysis revealed a single recessive genescp-1that was responsible for the SCP mutation. Map-based cloning combined with a modified MutMap identifiedCsCYP85A1, a member of the plant cytochrome P450 monooxygenase gene family, as the most possible candidate gene forscp-1, which encodes a BR-C6-oxidase in the BR biosynthesis pathway. We show that a SNP within the second exon ofscp-1candidate gene caused the SCP phenotype. Three copies of theCsCYP85Agene are present in the cucumber genome, but only thescp-1/CsCYP85A1gene seemed active. The expression ofCsCYP85A1was higher in flowers than in the leaves and stem; its expression in the wild type (WT) was feedback regulated by BL application. Its expression was reduced in C257 as compared with the WT. This was the first report of map-based cloning of a plant height gene in cucurbit crops. The research highlighted the combined use of linkage mapping, an improved MutMap method and allelic diversity analysis in natural populations in quick cloning of simply inherited genes in cucumber. The roles ofCsCYP85A1in regulation of internode elongation in cucumber was discussed.
authors.affiliation: Horticulture College, Northwest A&F University Yangling, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Wang
authors.affiliation: Horticulture College, Northwest A&F University Yangling, China.
authors.forename: Wanqing
authors.initials: W
authors.lastname: Li
authors.affiliation: Horticulture College, Northwest A&F University Yangling, China.
authors.forename: Yaguang
authors.initials: Y
authors.lastname: Qin
authors.affiliation: Horticulture College, Northwest A&F UniversityYangling, China; Horticulture Department, University of Wisconsin, MadisonWI, USA.
authors.forename: Yupeng
authors.initials: Y
authors.lastname: Pan
authors.affiliation: Horticulture College, Northwest A&F University Yangling, China.
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Wang
authors.affiliation: Horticulture Department, University of Wisconsin, MadisonWI, USA; Vegetable Crops Research Unit, United States Department of Agriculture-Agricultural Research Service, MadisonWI, USA.
authors.forename: Yiqun
authors.initials: Y
authors.lastname: Weng
authors.affiliation: College of Life Science, Northwest A&F University, Yangling China.
authors.forename: Peng
authors.initials: P
authors.lastname: Chen
authors.affiliation: Horticulture College, Northwest A&F University Yangling, China.
authors.forename: Yuhong
authors.initials: Y
authors.lastname: Li
keywords: BR biosynthesis; CYP85A1; cucumber; cytochrome P450; dwarf; plant architecture