De novo assembly and analysis of the Pugionium cornutum (L.) Gaertn. transcriptome and identification of genes involved in the drought response.[Pubmed: 28552570]

Pugionium cornutum (L.) Gaertn. is a xerophytic plant species widely distributed in sandy and desert habitats in northwest China. However, the molecular mechanism of drought tolerance in P. cornutum has received little attention. At present, there is limited available transcriptome information for P. cormutum in public databases. Illumina sequencing was used to identify drought-responsive genes and to further characterize the molecular basis of drought tolerance in P. cornutum. In total, 51,385 unigenes with an average length of 825.32bp were obtained by de novo transcriptome assembly. Among these unigenes, 35,276 were annotated with gene descriptions, conserved domains, gene ontology terms, and metabolic pathways. In addition, the results showed that differentially expressed genes (DEGs) were mainly involved in photosynthesis, nitrogen metabolism, and plant hormone signal transduction pathways, notably ascorbate and aldarate metabolism, which could be an alternative pathway to enhance antioxidant capacity in P. cornutum in response to drought stress. These results provide an important clue about the effects of accumulation of ROS on ascorbic acid biosynthesis in P. cornutum. In addition, we found that transcription of most genes involved in ascorbic acid metabolism was altered under drought stress. Additionally, 93 drought-inducible transcription factor genes were identified in the DEGs under drought conditions; these included DREB, AP2/EREBP, B-2a, ERF2, MYB and Zinc finger family. The results of this study provide further insight into the molecular mechanisms of stress tolerance in P. cornutum, and also identify some attractive candidate genes and valuable information for improving drought stress tolerance in other species through genetic engineering.

Compositional and gastrointestinal prokinetic studies of Pugionium (L.).[Pubmed: 25976823]

Pugionium cornutum (L.) Gaertn. (PCG) is a desert plant with edible and medicinal value. The contents of proximate composition, amino acids and vitamins of fresh and pickled PCG were analyzed. PCG is rich in dietary fiber, protein and vitamins. PCG is a dietary source of potassium and calcium, with low levels of fat and sugar. PCG contains all the 18 hydrolyzed amino acids. Pickled PCG protein is a high quality protein. A large quantity of vitamins are lost during the pickling process. The type and number of mice dejections, gastric emptying and intestinal propulsion were investigated using the water extract of fresh and pickled PCG (WEFP and WEPP) to determine their gastrointestinal prokinetic efficacy. The low-dose WEFP and WEPP promoted the gastrointestinal dynamics and the WEFP and WEPP promoted gastrointestinal activity and act as nonviolent drugs. The results indicate that PCG has great potential as a new functional food source.

Pleistocene climate change and the origin of two desert plant species, Pugionium cornutum and Pugionium dolabratum (Brassicaceae), in northwest China.[Pubmed: 23550542]

Pleistocene climate change has had an important effect in shaping intraspecific genetic variation in many species; however, its role in driving speciation is less clear. We examined the possibility of a Pleistocene origin of the only two representatives of the genus Pugionium (Brassicaceae), Pugionium cornutum and Pugionium dolabratum, which occupy different desert habitats in northwest China. We surveyed sequence variation for internal transcribed spacer (ITS), three chloroplast (cp) DNA fragments, and eight low-copy nuclear genes among individuals sampled from 11 populations of each species across their geographic ranges. One ITS mutation distinguished the two species, whereas mutations in cpDNA and the eight low-copy nuclear gene sequences were not species-specific. Although interspecific divergence varied greatly among nuclear gene sequences, in each case divergence was estimated to have occurred within the Pleistocene when deserts expanded in northwest China. Our findings point to the importance of Pleistocene climate change, in this case an increase in aridity, as a cause of speciation in Pugionium as a result of divergence in different habitats that formed in association with the expansion of deserts in China.