Identification and Fine Mapping of a Locus Related to Leaf Up-Curling Trait (Bnuc3) in Brassica napus

Abstract

Leaf trait is an important target trait in crop breeding programs. Moderate leaf curling may be a help for improving crop yield by minimizing the shadowing by leaves. Mining locus for leaf curling trait is of significance for plant genetics and breeding researches. The present study identified a novel rapeseed accession with up-curling leaf, analyzed the up-curling leaf trait inheritance, and fine mapped the locus for up-curling leaf property (Bnuc3) in Brassica napus. Genetic analysis revealed that the up-curling leaf trait is controlled by a single dominant locus, named BnUC3. We performed an association study of BnUC3 with single nucleotide polymorphism (SNP) markers using a backcross population derived from the homozygous up-curling leaf line NJAU-M1295 and the canola variety ‘zhongshuang11’ with typical flat leaves, and mapped the BnUC3 locus in a 1.92 Mb interval of chromosome A02 of B. napus. To further map BnUC3, 232 simple sequence repeat (SSR) primers and four pairs of Insertion/Deletion (InDel) primers were developed for the mapping interval. Among them, five SSR markers and two InDel markers were polymorphic. By these markers, the mapping interval was narrowed to 92.0 kb using another F2 population. This fine mapping interval has 11 annotated genes among which BnaA02T0157000ZS were inferred to be candidate casual genes for up-curling leaf based on the cloned sequence analysis, gene functionality, and gene expression analysis. The current study laid a foundational basis for further elucidating the mechanism of BnUC3 and breeding of variety with up-curling leaf.

Fine Mapping of a Pleiotropic Locus (BnUD1) Responsible for the Up-Curling Leaves and Downward-Pointing Siliques in Brassica napus

“…Thus, the up-curling leaf trait should be explored in more detail. To date, three loci related to the up-curling leaf trait have been identified in B. napus (i.e., BnUC1 , BnUC2 , and BnUC3 ) [ 39 , 40 , 41 ]. In present work, we found that the Bnud1 mutant had an increased photosynthetic efficiency at seedling stage, and relatively small plant architecture ( Figure 1 ; Table 5 ).…”

“…Leaf morphological mutations in B. napus (e.g., upward and downward curling and wrinkling) are related to photosynthetic efficiency and affect the yield. Previous research on leaf curling revealed the associated loci and genes, including a dominant locus ( BnDWF/DCL1 ) [ 36 ], semi-dominant genes ( sca and ds-4 ) [ 37 , 38 ], and the genes ( BnUC1 , BnUC2 , and BnUC3 ) [ 39 , 40 , 41 ] responsible for the up-curling of B. napus leaves. Analyses of gene functions demonstrated that abnormalities in some leaf flatness-related traits are caused by the deficient expression of genes encoding proteins mediating phytohormone (e.g., auxin and brassinolide) biosynthesis or signaling [ 13 , 42 , 43 , 44 ].…”

Sweet potato NAC transcription factor NAC43 negatively regulates plant growth by causing leaf curling and reducing photosynthetic efficiency

“…In monocotyledonous plants, such as rice, the phenotype of leaf curling, in general, is caused by the change of bulliform cells ( Li et al., 2010 ; Fang et al., 2012 ; Li et al., 2016 ; Sun et al., 2020 ; Xu et al., 2021 ). On the other hand, leaf curling in dicotyledonous plants is mainly related to the adaxial–abaxial leaf polarity establishment, cutin and cuticular wax biosynthesis, and hormone responses ( Wan et al., 2021 ). The first gene associated with leaf polarity, phantastica ( PHAN ), was required for the elaboration of the proximodistal axis ( Waites and Hudson, 1995 ; Waites et al., 1998 ).…”