Morphological, cytological and molecular marker analyses of \u2018Tapestry\u2019 caladium variants reveal diverse genetic changes and enable association of leaf coloration pattern loci with molecular markers

Zhe Cao,Zhanao Deng

doi:10.1007/s11240-020-01922-2

Zhe Cao, Zhanao Deng

Open Access

https://doi.org/10.1007/s11240-020-01922-2

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Abstract

Somaclonal variation and induced mutation are highly valuable sources of genetic variation for genetic improvement and research in horticultural crops; cellular and molecular characterization can greatly facilitate their uses in these areas. In the present study, 20 caladium variants were identified among ‘Tapestry’ plants that were regenerated from leaf cultures treated with or without colchicine. These variants showed changes in leaf main vein color and coloration pattern and were separated into ten groups based on leaf morphological changes. Five variants contained 3.3–9.7% more nuclear DNA than the wildtype and gained one, two or three chromosomes, while four variants contained 3.0–4.8% less nuclear DNA and lost one chromosome. Five, out of 22, simple sequence repeat-based molecular markers detected DNA banding pattern changes in 13 of the 20 variants. Two molecular markers (CaM24 and CaM62) detected DNA banding pattern changes in the same four variants, suggesting that these two markers may be located in the same chromosomal segment. Strong association between leaf characteristics (leaf blotching and main vein color) and molecular banding pattern changes with molecular marker CaM42 were observed in six variants, indicating that CaM42 may be associated with gene loci controlling leaf blotching and leaf main vein color in caladium.

Highlights

Genetic variation/mutation is essential and vitally important for genetic improvement and development of new cultivars in crops
When the four variants previously reported by Cai et al (2015) were taken into account, a total of 13 variants were identified out of 441 regenerants from cultures exposed to colchicine treatments, and seven variants were observed among 60 regenerants from cultures not exposed to any colchicine treatments
To answer the question whether or not colchicine will induce genetic mutations beyond chromosome doubling in caladium, it may require the use of different types of explants/cultures and/or culturing conditions that give rise to much less somaclonal variation and won’t mask any potential mutagenic effects of colchicine

Summary

Introduction

Genetic variation/mutation is essential and vitally important for genetic improvement and development of new cultivars in crops. One important type of genetic variation is somaclonal variation that is induced during in vitro cell, tissue and organ. Somaclonal variants have been reported in numerous plants, and they can exhibit significant variability in morphological characters, physiological traits, and resistance or tolerance to biotic or abiotic stresses compared to the original (mother) plants from which the cells and tissues were taken for in vitro culture (Heinz et al 1977; Selby and Collin 1976; Sunderland 1977; Trujillo and Garcia 1996). Somaclonal variation has been used to create new phenotypes or cultivars in numerous crops. Somaclonal variations have resulted in nearly 80 new cultivars in Aglaonema, Alocasia, Anthurium, Calathea, Dieffenbachia, Philodendron, Spathphyllum, and Sygonium (Chen et al 2003; Chen and Henny 2008; Henny et al 2003)

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