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. 2016 May 12;4:e2017. doi: 10.7717/peerj.2017

Figure 3. Possible evolutionary relationship of PhAGL6b in the regulation of lip formation and floral symmetry in Phalaenopsis orchid.

Figure 3

(A) Wild-type flower. (B) A big lip mutant of Phalaenopsis World Class ‘Big Foot.’ (C) Representative RT-PCR result showing the mRNA splicing pattern of PhAGL6b in wild-type (W) and big lip mutant (M). (D) Alignment of the amino acid sequences of alternatively spliced forms of PhAGL6b. (E) Model of PhAGL6b spatial expression for controlling Phalaenopsis floral symmetry. Ectopic expression of PhAGL6b in the distal domain (petal; pink), petal converts into a lip-like structure that leads to radial symmetry. Ectopic expression in proximal domain, (sepal; blue) sepal converts into a lip-like structure that leads to bilateral symmetry. The alternative processing of PhAGL6b transcripts produced in proximal domain (labellum; pink), labellum converts into a petal-like structure that leads to radial symmetry. PhAGL6b expression patterns in Phalaenopsis floral organs are either an expansion or a reduction across labellum. This implies that PhAGL6b may be a key regulator to the bilateral or radially symmetrical evolvements. Pink color: 2nd whorl of the flower; blue color: 1st whorl of the flower.