RESUMEN
PREMISE OF THE STUDY: Transcriptomes were used to develop microsatellite markers for the plant genus Orinus (Poaceae), which comprises three species of grasses (O. thoroldii, O. kokonoricus, and O. intermedius) that are widely distributed in the Qinghai-Tibetan Plateau. METHODS AND RESULTS: Primer pairs were developed for 16 high-quality simple sequence repeats (SSRs) using transcriptomes. SSRs were amplified in 248 individuals representing the three species of Orinus; the number of alleles per locus ranged from one to seven, with an average of 2.6. The expected and observed heterozygosity per locus varied from 0.00 to 0.83 and from 0.00 to 1.00, respectively, with respective mean values of 0.32 and 0.34. CONCLUSIONS: These newly developed SSR markers will be valuable for evaluating the population genetic structure of Orinus throughout its range.
RESUMEN
4-Coumarate:CoA ligase (4CL) genes are critical for the biosynthesis of plant phenylpropanoids. Here we identified 20 4CL genes in the genomes of two desert poplars (Populus euphratica and P. pruinosa) and salt-sensitive congener (P. trichocarpa), but 12 in Salix suchowensis (Salix willow). Phylogenetic analyses clustered all Salicaceae 4CL genes into two clades, and one of them (corresponding to the 4CL-like clade from Arabidopsis) showed signals of adaptive evolution, with more genes retained in Populus than Salix and Arabidopsis. We also found that 4CL12 (in 4CL-like clade) showed positive selection along the two desert poplar lineages. Transcriptional profiling analyses indicated that the expression of 4CL2, 4CL11, and 4CL12 changed significantly in one or both desert poplars in response to salt stress compared to that of in P. trichocarpa. Our results suggest that the evolution of the 4CL genes may have contributed to the development of salt tolerance in the two desert poplars.