A natural hybrid of Impatiens, in the introduced range, demonstrated by sequence analysis of the nuclear ribosomal DNA-gene repeat

ABSTRACT

In a nature reserve, in Ticino canton in Switzerland amidst a mixed population of non-native Impatiens parviflora and I. glandulifera aberrant plants of I. parviflora were observed. A herbarium voucher and seeds were collected and seedlings subsequently raised in a greenhouse. Molecular analysis for ITS region and chloroplast markers revealed the plants to be a hybrid between I. parviflora and I. balfourii, another non-native Impatiens species occurring in the Ticino canton. No crossing out nor reduced fertility was observed in F2 and F3 generations, raised in a greenhouse. Sizeable populations of the hybrid have been observed in 2014 in the Ticino canton in the absence of the parental species. Nuclear genome size as measured by flow cytometry with propidium iodide did not indicate polyploidy and the ITS region remained 100% uniform. Therefore a homoploid hybrid speciation event is assumed.

KEYWORDS:

• Hybridization
• invasive species
• Impatiens
• ITS
• DNA barcoding

Acknowledgments

The authors would like to thank Info Flora and the Natural History Museum of Ticino for providing the information on the historical records of Impatiens species in Ticino. The Botanical Garden Leiden provided facilities for the first germination trials in 2013. Ben Zonneveld (Naturalis Biodiversity Center Leiden) is acknowledged for the flow cytometry measurements and Ronald van den Berg and Rob Tanner for critically reading the manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Data Accessibilty

DNA sequences: ITS, rbcL, and the trnh-psbA intergenic spacer sequences were deposited in NCBI Genbank under the following accession numbers: ITS: MK161037-MK161040; rbcL: MK158963-MK158966; and trnh-psbA: MK158967-MK158970. Sequences will also be made available at http://www.q-bank.eu/Plants/

Herbarium vouchers are available at L, LUG, WAG-PD and online at http://www.q-bank.eu/Plants/

Supplementary material

Supplementary data for this article can be accessed here.

Additional information

Notes on contributors

J.L.C.H. van Valkenburg

J.L.C.H. van Valkenburg is senior botanist at the National Plant Protection Organization of the Netherlands. He focusses on invasive alien plants. He conceived and designed the experiment and collected the field data. He drafted the manuscript.

N. Schoenenberger

N. Schoenenberger is Managing Director at Innovabridge and Curator at the Cantonal museum of Natural History in Lugano. He worked in plant biology and plant genetics. He conceived and designed the experiment and collected the field data.

B.T.L.H. van de Vossenberg

B.T.L.H. van de Vossenberg and W.A. Man in ’t Veld are both senior specialists molecular biology at the National Plant Protection Organization in the Netherlands. They both performed the analysis of the molecular data.

M. Westenberg

M. Westenberg is a senior specialist molecular biology at the National Plant Protection Organization in the Netherlands. He performed the analysis of the molecular data and drafted the manuscript.

E. Boer

E. Boer is a researcher and database manager at the National Plant Protection Organization in the Netherlands. He focusses on invasive alien plants. He was instrumental in the greenhouse experiments and drafted the manuscript.