The Hundred Horses Chestnut: a model system for studying mutation rate during clonal propagation in superior plants

The Hundred Horses Chestnut is a monumental European chestnut (Castanea sativa Mill.) of an estimated age of 2000-3000 years living in Sicily (Italy). Its value as a model plant was here explored by ascertaining its genetic uniformity. Two different kinds of molecular markers, already in use for chestnut varieties identification, were used in the present work for analysing the DNA isolated from eight different points of its foliage. Results document that the three trunks that now form the monumental tree originated from the same seed, and could came, therefore, by the radial fragmentation of a main trunk as hypothesized and argued since 1815. A detailed genetic fingerprint of the tree is provided that can be used for tracking its clones worldwide. The confirm of the genetic uniformity of the tree also corroborates the hypothesis concerning its age and confirms that the plant is a good model system for studying genetic intra-varietal variability deriving from the accumulation of somatic mutations. In fact, chestnut cultivars, that are vegetatively propagated, have more recent origin and can therefore be considered at least as homogeneous as the different parts of the Hundred Horses Chestnut foliage. First results are discussed, and perspectives are pointed out for studies about somatic mutations in monumental trees.

Automated summary

This study explored the genetic uniformity and value of the Hundred Horses Chestnut as a model plant. The results confirmed the age of the tree and its origin from the radial fragmentation of a main trunk. The genetic fingerprint obtained can be used to track the clones of the tree worldwide.