Haploids in Conifer Species: Characterization and Chromosomal Integrity of a Maritime Pine Cell Line

José Cabezas,Luis Díaz,María Cervera,Marian Morcillo,Isabel Arrillaga,María Vélez,Juan Segura

doi:10.3390/f7110274

Abstract

Haploids are a valuable tool for genomic studies in higher plants, especially those with huge genome size and long juvenile periods, such as conifers. In these species, megagametophyte cultures have been widely used to obtain haploid callus and somatic embryogenic lines. One of the main problems associated with tissue culture is the potential genetic instability of the regenerants. Because of this, chromosomal stability of the callus and/or somatic embryos should also be assessed. To this end, chromosome counting, flow cytometry and genotyping using microsatellites have been reported. Here, we present an overview of the work done in conifers, with special emphasis on the production of a haploid cell line in maritime pine (Pinus pinaster L.) and the use of a set of molecular markers, which includes Single Nucleotide Polymorphisms (SNPs) and microsatellites or Single Sequence Repeats (SSRs), to validate chromosomal integrity confirming the presence of all chromosomic arms.

Highlights

Haploid tissues are valuable for genomic studies and breeding purposes in higher plants, especially those with huge genomes and long juvenile periods, such as conifers
The ploidy level of the L5 line was tested by karyological, flow cytometry
The ploidy level of the L5 line was tested by karyological, flow cytometry analyses and 7 Single Sequence Repeats (SSRs) markers [19]

Summary

Introduction

Haploid tissues are valuable for genomic studies and breeding purposes in higher plants, especially those with huge genomes and long juvenile periods, such as conifers. To this end, megagametophytes and, to a lesser extent, microsporophylls (i.e., pollen grains), have been used as a source of material. The reduced amount DNA that can be obtained from a single megagametophyte may be insufficient to sequence these large genomes [5] To follow this approach, it is essential to generate a genetically stable haploid cell line derived from in vitro grown tissues for each targeted species

Methods

Results

Discussion

Conclusion