Genomic insights into salt adaptation in a desert poplar

Abstract

Despite the high economic and ecological importance of forests, our knowledge of the genomic evolution of trees under salt stress remains very limited. Here we report the genome sequence of the desert poplar, Populus euphratica, which exhibits high tolerance to salt stress. Its genome is very similar and collinear to that of the closely related mesophytic congener, P. trichocarpa. However, we find that several gene families likely to be involved in tolerance to salt stress contain significantly more gene copies within the P. euphratica lineage. Furthermore, genes showing evidence of positive selection are significantly enriched in functional categories related to salt stress. Some of these genes, and others within the same categories, are significantly upregulated under salt stress relative to their expression in another salt-sensitive poplar. Our results provide an important background for understanding tree adaptation to salt stress and facilitating the genetic improvement of cultivated poplars for saline soils.

NaCl-elicited, vacuolar Ca2+ release facilitates prolonged cytosolic Ca2+ signaling in the salt response of Populus euphratica cells

“…Populus euphratica is a salt-resistant model species often used to elucidate physiological and molecular mechanisms underlying salt tolerance in woody plants [32][33][34][35][36]. In this study, P. euphratica cell cultures were used as a model system for investigating salt signaling network.…”

A transient gene expression system in Populus euphratica Oliv. protoplasts prepared from suspension cultured cells

“…Suspension cultured cells were used to examine the selective ion uptake, salt exclusion, and ion compartmentation of individual P. euphratica cells (Chen et al 2000;Ma et al 2002;Gu et al 2004). Gene expression and metabolite profiling , microRNA analysis , and genome sequencing (Ma et al 2013) were carried out to find genes involved in the salt tolerance of P. euphratica. However, only a few salt tolerance genes have been identified, and most of them originate from annual herbaceous plants.…”

A System for Dosage-Based Functional Genomics in Poplar

“…For example, in animals, copy number variation has major effects on developmental traits and disease (Henrichsen et al, 2009;Craddock et al, 2010;Stankiewicz and Lupski, 2010;Alvarez and Akey, 2012). In plants, copy number variation has been identified in multiple species and demonstrated to affect important agronomic traits (Horiguchi et al, 2009;Pearce et al, 2011;Cook et al, 2012;Díaz et al, 2012;Li et al, 2012;Wingen et al, 2012;Ma et al, 2013). On a wider scale, when lesions encompass a larger chromosomal region or even an entire chromosome, gene dosage effects are responsible for aneuploidy syndromes.…”