Multiple haploids, triploids, and tetraploids found in modern-day \u201cliving fossil\u201d Ginkgo biloba

Petr Šmarda,Laszlo Orlóci,Martin Dieck,Petr Bureš,Lucie Horová,Laszlo Papp,Kristýna Veselá,Pavel Veselý,Heidi Dieck,Ondřej Knápek,Pavel Hrubík,Katarína Ražná

doi:10.1038/s41438-018-0055-9

Petr Šmarda, Laszlo Orlóci + Show 10 more

Open Access

https://doi.org/10.1038/s41438-018-0055-9

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Abstract

Ginkgo biloba, the last extant representative of a lineage of Mesozoic gymnosperms, is one of the few seed plants with an exceptionally long (~300 Myr) evolutionary history free of genome-wide duplications (polyploidy). Despite this genome conservatism, we have recently found a viable spontaneous tetraploid Ginkgo sapling during routine screening of several plants, demonstrating that natural polyploidy is possible in Ginkgo. Here we provide a much wider flow cytometry survey of ploidy in some European Ginkgo collections, and own seedlings (>2200 individuals and ~200 cultivars). We found a surprisingly high level of ploidy variation in modern-day Ginkgo and documented altogether 13 haploid, 3 triploid, and 10 tetraploid Ginkgo plants or cultivars, most of them being morphologically distinct from common diploids. Haploids frequently produced polyploid (dihaploid) buds or branches. Tetraploids showed some genome size variation. The surveyed plants provide a unique resource for future Ginkgo research and breeding, and they might be used to accelerate the modern diversification of this nearly extinct plant lineage.

Highlights

Introduction Ginkgo bilobaL. is the last representative of Ginkgoales, a group of gymnosperms that was an important component of “temperate” forest in the Mesozoic[1,2]
We recently found a viable spontaneous tetraploid Ginkgo sapling in the Botanical Garden of Masaryk University in Brno, Czech Republic (Table 1) during routine genome size screening of some plants grown from the seeds of three females cultivated in this garden[26]
In addition to exact ploidy detection and genome size estimations using flow cytometry, we investigated the possibility of ploidy identification by measurement of stomatal guard cells and pores

Summary

Introduction

L. is the last representative of Ginkgoales, a group of gymnosperms that was an important component of “temperate” forest in the Mesozoic[1,2]. Its distribution was dramatically reduced during the Quaternary and the most recent ice ages, and only a few populations survived in isolated locations in China[5,6]. Though these locations are considered natural refugia, Ginkgo survival was undoubtedly supported by its widespread planting by Buddhistic monks[5]. The phylogenetic uniqueness, the ancient nature, and the persistent morphological resemblance of Ginkgo biloba to its fossil relatives lead people to call it a “living fossil”

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