Highly endoreduplicated floral organs of somaclonal variants in clonally propagated Phalaenopsis ‘Spring Dancer’

• Published in: Plant cell, tissue and organ culture Vol. 126; no. 1; pp. 67 - 77
• Main Authors: Lee, Hyun-Jeong, Kim, Young-Eun, Yoon, Yeo-Joong, Jeong, Cheol-Seung, Lian, Mei Lan, Paek, Kee-Yoeup, Park, So-Young
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.07.2016; Springer Nature B.V
• Subjects: Biomedical and Life Sciences; Endoreduplication; Flowers; Leaves; Life Sciences; Micropropagation; Morphology; Organs; Original Article; Petals; Phalaenopsis; Plant Genetics and Genomics; Plant Pathology; Plant Physiology; Plant propagation; Plant Sciences; Ploidy; Somaclonal variation; Nuclei ploidy level; Gene expression; Somaclonal variants; Histological observation
• ISSN: 0167-6857; 1573-5044
• DOI: 10.1007/s11240-016-0977-6

A micropropagation system is essential for obtaining elite clones of Phalaenopsis in the floricultural industry; however, somaclonal variation frequently occurs during long-term micropropagation, which reduces the uniformity and quality of clonally propagated plants. To detect the factors influencing this variation and thus obtain high-quality, uniform Phalaenopsis plants, we analyzed somaclonal variants in the Phalaenopsis ‘Spring Dancer’ (SD) variety collected from an orchid farm, which were grouped into three types according to flower morphology (SD-N, SD-V1, SD-V2). Morphological differences were observed between all SD groups; in particular, the diameter of the petal and thickness of each organ were significantly larger in the variants than SD-N (normal) plants. Both SD variant groups showed the same ploidy level as that of SD-N. The degree of endoreduplication of the petals and flower stalks was higher in the variants (4C–16C) than in SD-N (2C–8C). Cell area was increased and the shape of epidermal cells was changed in both variants. Expression levels of MADS box transcription factor ( MADS4 ) of the flowers were higher than those of the leaves in the variants. Among the three flower organs, MADS4 expression was the highest in the petals of SD-V2. These results revealed that MADS4 is involved in the modification of flower morphology in somaclonal SD variants. High ploidy 2 ( HPY2 ) expression was highest in the flowers of SD-V1, whereas its expression in the leaf was similar to that of SD-N. Among the various flower organs, HPY2 expression was highest in the lips of SD-V1.