title: Repeated evolution of salt-tolerance in grasses.
abstract: The amount of salt-affected agricultural land is increasing globally, so new crop varieties are needed that can grow in salt-affected soils. Despite concerted effort to develop salt-tolerant cereal crops, few commercially viable salt-tolerant crops have been released. This is puzzling, given the number of naturally salt-tolerant grass species. To better understand why salt-tolerance occurs naturally but is difficult to breed into crop species, we take a novel, biodiversity-based approach to its study, examining the evolutionary lability of salt-tolerance across the grass family. We analyse the phylogenetic distribution of naturally salt-tolerant species on a phylogeny of 2684 grasses, and find that salt-tolerance has evolved over 70 times, in a wide range of grass lineages. These results are confirmed by repeating the analysis at genus level on a phylogeny of over 800 grass genera. While salt-tolerance evolves surprisingly often, we find that its evolution does not often give rise to a large clade of salt-tolerant species. These results suggest that salt-tolerance is an evolutionarily labile trait in grasses.
authors: Centre for Macroevolution and Macroecology, Research School of Biology, Australian National University, Canberra, Australian Capital Territory 0200, Australia. tom.bennett@anu.edu.au
authors: T H
authors: TH
authors: Bennett
authors: T J
authors: TJ
authors: Flowers
authors: L
authors: L
authors: Bromham
mesh_terms: D000222:Adaptation, Physiological; D005075:Biological Evolution; D003198:Computer Simulation; D030541:Databases, Genetic; D006239:Haplotypes; D016013:Likelihood Functions; D010802:Phylogeny; D006109:Poaceae / Q000145:classification / Q000235:genetics / Q000502:physiology*; D054712:Salinity; D055051:Salt-Tolerant Plants / Q000145:classification / Q000235:genetics / Q000502:physiology*; D012987:Soil; D013045:Species Specificity
chemical_list: D012987:Soil