Variation in Splicing Efficiency Underlies Morphological Evolution in Capsella

Publication date: Available online 21 December 2017
Source:Developmental Cell
Author(s): Ushio Fujikura, Runchun Jing, Atsushi Hanada, Yumiko Takebayashi, Hitoshi Sakakibara, Shinjiro Yamaguchi, Christian Kappel, Michael Lenhard
Understanding the molecular basis of morphological change remains a central challenge in evolutionary-developmental biology. The transition from outbreeding to selfing is often associated with a dramatic reduction in reproductive structures and functions, such as the loss of attractive pheromones in hermaphroditic Caenorhabditis elegans and a reduced flower size in plants. Here, we demonstrate that variation in the level of the brassinosteroid-biosynthesis enzyme CYP724A1 contributes to the reduced flower size of selfing Capsella rubella compared with its outbreeding ancestor Capsella grandiflora. The primary transcript of the C. rubella allele is spliced more efficiently than that of C. grandiflora, resulting in higher brassinosteroid levels. These restrict organ growth by limiting cell proliferation. More efficient splicing of the C. rubella allele results from two de novo mutations in the selfing lineage. Thus, our results highlight the potentially widespread importance of differential splicing efficiency and higher-than-optimal hormone levels in generating phenotypic variation.

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Teaser

Reduced reproductive structures are often associated with the transition from outbreeding to selfing in an organism. Fujikura, Jing et al. address the molecular basis of morphological evolution in the selfing plant Capsella rubella. Evolutionarily derived variations in CYP724A1 increase splicing efficiency and contribute to reduced petal size through higher-than-optimal brassinosteroid levels.


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