Dryas as a Model for Studying the Root Symbioses of the Rosaceae.

Benjamin Billault-Penneteau,Katharina Pawlowski,Martin Parniske,Aline Sandré,Jessica Folgmann

doi:10.3389/fpls.2019.00661

Benjamin Billault-Penneteau, Katharina Pawlowski + Show 3 more

Open Access

https://doi.org/10.3389/fpls.2019.00661

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Abstract

The nitrogen-fixing root nodule symbiosis is restricted to four plant orders: Fabales (legumes), Fagales, Cucurbitales and Rosales (Elaeagnaceae, Rhamnaceae, and Rosaceae). Interestingly all of the Rosaceae genera confirmed to contain nodulating species (i.e., Cercocarpus, Chamaebatia, Dryas, and Purshia) belong to a single subfamily, the Dryadoideae. The Dryas genus is particularly interesting from an evolutionary perspective because it contains closely related nodulating (Dryas drummondii) and non-nodulating species (Dryas octopetala). The close phylogenetic relationship between these two species makes Dryas an ideal model genus to study the genetic basis of nodulation by whole genome comparison and classical genetics. Therefore, we established methods for plant cultivation, transformation and DNA extraction for these species. We optimized seed surface sterilization and germination methods and tested growth protocols ranging from pots and Petri dishes to a hydroponic system. Transgenic hairy roots were obtained by adapting Agrobacterium rhizogenes-based transformation protocols for Dryas species. We compared several DNA extraction protocols for their suitability for subsequent molecular biological analysis. Using CTAB extraction, reproducible PCRs could be performed, but CsCl gradient purification was essential to obtain DNA in sufficient purity for high quality de novo genome sequencing of both Dryas species. Altogether, we established a basic toolkit for the culture, transient transformation and genetic analysis of Dryas sp.

Highlights

Nitrogen and phosphate are key nutrients for plant growth, but their availability is limited, especially in alkaline and calcareous soils (Vitousek et al, 2010; Lambers et al, 2012)
We present the advances achieved in the development and adaptation of protocols in order to use Dryas as a model genus in Rosaceae research as well as to study the evolution of root symbioses
To establish Dryas as new model genus in the laboratory, we developed cultivation protocols under controlled conditions

Summary

Introduction

Nitrogen and phosphate are key nutrients for plant growth, but their availability is limited, especially in alkaline and calcareous soils (Vitousek et al, 2010; Lambers et al, 2012). We present the advances achieved in the development and adaptation of protocols in order to use Dryas as a model genus in Rosaceae research as well as to study the evolution of root symbioses.

Results

Conclusion