In plants, glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is a main enzyme in the glycolytic pathway. It plays an essential role in glycerolipid metabolism and response to various stresses. To examine the function of PsGAPDH (Pleurotus sajor-caju GAPDH) in response to abiotic stress, we generated transgenic rice plants with single-copy/intergenic/homozygous overexpression PsGAPDH (PsGAPDH-OX) and investigated their responses to salinity stress. Seedling growth and germination rates of PsGAPDH-OX were significantly increased under salt stress conditions compared to those of the wild type. To elucidate the role of PsGAPDH-OX in salt stress tolerance of rice, an Illumina HiSeq 2000 platform was used to analyze transcriptome profiles of leaves under salt stress. Analysis results of sequencing data showed that 1124 transcripts were differentially expressed. Using the list of differentially expressed genes (DEGs), functional enrichment analyses of DEGs such as Gene Ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were performed. KEGG pathway enrichment analysis revealed that unigenes exhibiting differential expression were involved in starch and sucrose metabolism. Interestingly, trehalose-6-phosphate synthase (TPS) genes, of which expression was enhanced by abiotic stress, showed a significant difference in PsGAPDH-OX. Findings of this study suggest that PsGAPDH plays a role in the adaptation of rice plants to salt stress.

The glycolytic pathway involves phosphofructokinase (PFK), a rate-limiting enzyme that catalyzes the phosphorylation of fructose-6-phosphate. In plants, the two PFK members are ATP-dependent phosphofructokinase (PFK) and pyrophosphate-fructose-6-phosphate phosphotransferase (PFP). However, the functions of the PFK family members in Quercus rubra are not well understood. The purpose of this study was to investigate the genome-wide distribution of the PFK family members and their roles in Q. rubra by performing a systematic study of the phylogenetic relationships, molecular characteristics, motifs, chromosomal and subcellular locations, and cis-elements of QrPFKs. We identified 14 QrPFK genes in the genome of Q. rubra, followed by examining their expression in different tissues, including the roots, stems, and leaves. The phylogenetic tree divided the 14 QrPFK genes into two groups: 11 belonging to PFK and three belonging to PFP. The expression profiles of all 14 proteins were relatively the same in leaves but differed between stems and roots. Four genes (Qurub.02G189400.1, Qurub.02G189400.2, Qurub.09G134300.1, and Qurub.09G134300.2) were expressed at very low levels in both stems and roots, while two (Qurub.05G235500.1 and Qurub.05G235500.1) were expressed at low levels and the others showed relatively high expression in all tissues.

Drought stress affects plant productivity by altering plant responses at the morphological, physiological, and molecular levels. In this study, we identified physiological and genetic responses in Populus alba × Populus glandulosa hybrid clones 72-30 and 72-31 after 12 days of exposure to drought treatment. After 12 days of drought treatment, glucose, fructose, and sucrose levels were significantly increased in clone 72-30 under drought stress. The Fv/Fo and Fv/Fm values in both clones also decreased under drought stress. The changes in proline, malondialdehyde, and H₂O₂ levels were significant and more pronounced in clone 72-30 than in clone 72-31. The activities of antioxidant-related enzymes, such as catalase and ascorbate peroxidase, were significantly higher in the 72-31 clone. To identify drought-related genes, we conducted a transcriptomic analysis in P. alba × P. glandulosa leaves exposed to drought stress. We found 883 up-regulated and 305 down-regulated genes in the 72-30 clone and 279 and 303 in the 72-31 clone, respectively. These differentially expressed genes were mainly in synthetic pathways related to proline, abscisic acid, and antioxidants. Overall, clone 72-31 showed better drought tolerance than clone 72-30 under drought stress, and genetic changes also showed different patterns.

Physiological response and transcriptome changes were observed to investigate the effects on the growth, metabolism and genetic changes of Pinus densiflora grown for a long time in an environment with an elevated atmospheric CO₂ concentration. Pine trees were grown at ambient (400 ppm) and elevated (560 ppm and 720 ppm) CO₂ concentrations for 10 years in open-top chambers. The content of nonstructural carbohydrates was significantly increased in elevated CO₂. It was notable that the contents of chlorophylls significantly decreased at an elevated CO₂. The activities of antioxidants were significantly increased at an elevated CO₂ concentration of 720 ppm. We analyzed the differences in the transcriptomes of Pinus densiflora at ambient and elevated CO₂ concentrations and elucidated the functions of the differentially expressed genes (DEGs). RNA-Seq analysis identified 2415 and 4462 DEGs between an ambient and elevated CO₂ concentrations of 560 ppm and 720 ppm, respectively. Genes related to glycolysis/gluconeogenesis and starch/sucrose metabolism were unchanged or decreased at an elevated CO₂ concentration of 560 ppm and tended to increase at an elevated CO₂ concentration of 720 ppm. It was confirmed that the expression levels of genes related to photosynthesis and antioxidants were increased at an elevated CO₂ concentration of 720 ppm.

Global climate change is heavily affected by an increase in CO₂. As one of several efforts to cope with this, research on poplar, a representative, fast growing, and model organism in plants, is actively underway. The effects of elevated atmospheric CO₂ on the metabolism, growth, and transcriptome of poplar were investigated to predict productivity in an environment where CO₂ concentrations are increasing. Poplar trees were grown at ambient (400 ppm) or elevated CO₂ concentrations (1.4× ambient, 560 ppm, and 1.8× ambient, 720 ppm) for 16 weeks in open-top chambers (OTCs). We analyzed the differences in the transcriptomes of Populusalba × Populus glandulosa clone “Clivus” and Populus euramericana clone “I-476” using high-throughput sequencing techniques and elucidated the functions of the differentially expressed genes (DEGs) using various functional annotation methods. About 272,355 contigs and 207,063 unigenes were obtained from transcriptome assembly with the Trinity assembly package. Common DEGs were identified which were consistently regulated in both the elevated CO₂ concentrations. In Clivus 29, common DEGs were found, and most of these correspond to cell wall proteins, especially hydroxyproline-rich glycoproteins (HRGP), or related to fatty acid metabolism. Concomitantly, in I-476, 25 were identified, and they were related to heat shock protein (HSP) chaperone family, photosynthesis, nitrogen metabolism, and carbon metabolism. In addition, carbohydrate contents, including starch and total soluble sugar, were significantly increased in response to elevated CO₂. These data should be useful for future gene discovery, molecular studies, and tree improvement strategies for the upcoming increased-CO₂ environments.