In order to demonstrate the mechanism of promoting crop growth by the well-cellar style transplanting (WCST), this study analyzed the physiological, biochemical and transcriptomic characteristics of tobacco seedlings under WCST compared with the conventional transplanting (CT), in which seedlings were transplanted on membranes. The results showed that under WCST, the average air temperature and average relative humidity of the atmosphere were 22.29 ℃ and 97.10%, enhanced by 4.76 ℃ and 58.97% compared with CT, respectively. However, the average photosynthetically active radiation (PAR) was 221.57 μmol/(m2·s), reduced by 20.53% than CT. After transplanting, the plant height and maximum leaf area under WCST were significantly improved, and the leaf water potential was enhanced between 29.92% and 64.46%. Furthermore, superoxide dismutase (SOD), peroxidase (POD) activities and malonaldehyde (MDA) content were reduced by 14.48%, 8.86%, and 9.83% compared with CT (P＜0.05), respectively. There were 4 845 differentially expressed genes (DEGs) identified, including 2 693 down-regulated genes and 2 152 up-regulated genes according to transcriptome sequencing. Some down-regulated DEGs are significantly enriched in “oxidation-reduction process” and “oxidoreductase activity” according to gene ontology (GO) annotation. Some DEGs involved in “flavonoid biosynthesis” are significantly enriched according to Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis. WCST decreased the gene expressions of chalcone isomerase, flavanone-3-hydroxylase,flavonol synthase,flavonoid-3′-hydroxylase,andflavonol-3-O-glucoside L-rhamnosyltransferaserelated with flavonoid biosynthesis, and significantly reduced the contents of the dihydroquercetin, rutin, kaempferol-3-O-glucoside, quercetin-3-O-galactoside, luteolin, isorhamnetin-3-O-rutinoside and kaempferol-3-O-rutinoside. The higher air temperature, air relative humidity and lower PAR were beneficial to the growth and development of tobacco seedlings under WCST, which avoiding the adverse stress.
OsSPL transcription factor plays an important role in the development and stress response of rice (Oryza sativa) roots, leaves, floral organs, and ears. In this study, the OsSPL3 promoter was analyzed to explore the expression pattern of OsSPL3 transcription factor in rice and its response to drought stress. The Cis-acting elements in the OsSPL3 promoter region were analyzed by PLACE and Plant CARE online softwares, and the recombinant expression vector of OsSPL3 promoter and β-glucuronidase(GUS) gene was constructed, which was transformed into ZH11 rice callus, and positive transgenic plants were obtained by screening. The GUS expression activity of pOsSPL3-GUS transgenic plants and the expression patterns under drought stress and abscisic acid (ABA) treatments were detected. The results of promoter analysis showed that in addition to the necessary transcription initiation core elements and light-responsive elements, the OsSPL3 promoter region also included three MYB-involved drought-inducible elements, three gibberellin-responsive elements, two anaerobic induction essential elements, one low temperature response element, one endosperm expression regulatory element, one zein metabolism regulatory element and one meristem expression-related regulatory element. The results of GUS staining showed that the expression activity of GUS gene in young leaves, stem sheaths, coleoptiles and other young tissues was high, as well as in the vigorous growth parts of roots such as root cap, meristem zone, and elongation zone. In addition, the drought stress could significantly enhanced the GUS activity of transgenic rice leaves and roots. It shows that OsSPL3 transcription factor plays a regulatory role in the process of coleoptile growth, new leaf formation, root extension and stem sheath elongation after seed germination, and OsSPL3 transcription factor is also involved in the response process of rice drought stress.
This experiment was carried out to investigate the effects of drought stress treatments during the grain-filling stage on the malt main qualities of the two barley genotypes, Zheda No. 9 (ZU9) (a cultivar) and XZ166 (a wild Tibetan barley accession), which differed greatly in the drought tolerance and malt quality, and had the similar heading and maturing stages. The results showed that drought stress significantly increased the malt protein and α-amino nitrogen contents, and the Kolbach index, and reduced malt extract rate and viscosity, with ZU9 being more largely affected than XZ166. Drought treatment at the early grain-filling stage (7 d after anthesis) caused much larger changes of all the examined malt qualities in ZU9 than in XZ166, while for the drought treatment at the middle grain-filling stage (14 d after anthesis), the changes of these quality traits were much larger in XZ166 than in ZU9. It may be concluded that drought stress occurred during the grain-filling stage had a great impact on malt quality, which should be addressed in breeding and agronomic management of malt. In the actual production, appropriate varieties should be selected according to the occurrence time of the drought, so as to avoid the drought stress during the critical period of quality formation.
In order to further explore the genes related to cold tolerance in cotton, we utilized transcriptome sequencing of leaf tissues of TM-1 (Gossypium hirsutum) and Hai7124 (G. barbadense) under cold treatment (4 ℃) and the control treatment (28 ℃) at different stages to compare and analyze their differences in cold tolerance related gene’s functions, expression patterns, and metabolic pathways. The results showed that Hai7124 was more sensitive to cold stress than TM-1, and its phenotype changed faster and more obviously under cold stress. Transcriptome analysis showed that TM-1 and Hai7124 contained 8 713 and 12 461 genes in response to cold stress, respectively. According to the orthologs between TM-1 and Hai7124, there were 1 518 and 3 577 specific response genes in TM-1 and Hai7124, respectively. Gene ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis showed that the specific response genes in TM-1 were mostly involved in hormone signal transduction, circadian rhythm, and other regulation processes, while specific response genes in Hai7124 were mostly involved in amino acid metabolism processes such as lysine, arginine, serine and threonine. Fatty acid metabolism genes related to cold tolerance and genes in key families of fatty acid synthesis pathways, such as acetyl-CoA carboxylase (ACC), fatty acid synthase (FAS), stearoyl-ACP desaturase (SAD), fatty acid desaturase (FAD), long chain acyl-CoA synthetase (LACS) from TM-1 and Hai7124 were further analyzed. During the whole cold stress treatment, TM-1 had 11 up-regulated genes, while Hai7124 had 10 down-regulated genes. The real time quantitative reverse polymerase chain reaction (RT-qPCR) was used to verify expression levels of five response genes. It was found that their expression levels were highly correlated with the expression levels of transcriptome. This study is helpful to analyze the molecular mechanism of different cold tolerance of TM-1 and Hai7124 and provide important genetic resources for the improvement of cold tolerance in cotton breeding.
