Fine mapping of the BnUC2 locus related to leaf up-curling and plant semi-dwarfing in Brassica napus

• Published in: BMC genomics Vol. 21; no. 1; p. 530
• Main Authors: Huang, Chengwei, Yang, Mao, Shao, Danlei, Wang, Yangming, Wan, Shubei, He, Jianbo, Meng, Zuqing, Guan, Rongzhan
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 31.07.2020; BioMed Central; BMC
• Subjects: Agronomy; Biosynthesis; Brassica; Brassica napus; Brassica napus - genetics; Chromosome Mapping; Chromosomes; Developmental biology; Efficiency; Gene expression; Gene mapping; Genes; Genetic aspects; Genomics; Germplasm; Harvesting; Identification and classification; Leaves; Lodging; Mapping; Markers; Morphology; Mutation; Nucleotides; Optimization; Phenotype; Phenotypic variations; Photosynthesis; Physiological aspects; Plant Breeding; Plant development; Plant growth; Plant Leaves - genetics; Planting density; Plants; Point mutation; Polymorphism; Populations; Progeny; Proteins; Quantitative trait loci; Rape (Plant); Semi-dwarf; Signal transduction; Simple sequence repeat; Single nucleotide polymorphism; Up-curled leaves; China; Brassica napus; Up-curled leaves; Semi-dwarf; Single nucleotide polymorphism; Gene mapping; Simple sequence repeat
• ISSN: 1471-2164; 1471-2164
• DOI: 10.1186/s12864-020-06947-7

Studies of leaf shape development and plant stature have made important contributions to the fields of plant breeding and developmental biology. The optimization of leaf morphology and plant height to improve lodging resistance and photosynthetic efficiency, increase planting density and yield, and facilitate mechanized harvesting is a desirable goal in Brassica napus. Here, we investigated a B. napus germplasm resource exhibiting up-curled leaves and a semi-dwarf stature. In progeny populations derived from NJAU5737 and Zhongshuang 11 (ZS11), we found that the up-curled leaf trait was controlled by a dominant locus, BnUC2. We then fine mapped the BnUC2 locus onto an 83.19-kb interval on chromosome A05 using single nucleotide polymorphism (SNP) and simple sequence repeat (SSR) markers. We further determined that BnUC2 was a major plant height QTL that explained approximately 70% of the phenotypic variation in two BC F family populations derived from NJAU5737 and ZS11. This result implies that BnUC2 was also responsible for the observed semi-dwarf stature. The fine mapping interval of BnUC2 contained five genes, two of which, BnaA05g16700D (BnaA05.IAA2) and BnaA05g16720D, were revealed by comparative sequencing to be mutated in NJAU5737. This result suggests that the candidate gene mutation (BnaA05g16700D, encoding Aux/IAA2 proteins) in the conserved Degron motif GWPPV (P63S) was responsible for the BnUC2 locus. In addition, investigation of agronomic traits in a segregated population indicated that plant height, main inflorescence length, and branching height were significantly reduced by BnUC2, whereas yield was not significantly altered. The determination of the photosynthetic efficiency showed that the BnUC2 locus was beneficial to improve the photosynthetic efficiency. Our findings may provide an effective foundation for plant type breeding in B. napus. Using SNP and SSR markers, a dominant locus (BnUC2) related to up-curled leaves and semi-dwarf stature in B. napus has been fine mapped onto an 83.19-kb interval of chromosome A05 containing five genes. The BnaA05.IAA2 is inferred to be the candidate gene responsible for the BnUC2 locus.