查看更多>>摘要：Iron is an essential micronutrient for plant growth and development. Here we provide evidence for a role of ERF96 in iron-deficiency response in Arabidopsis thaliana. The ERF96-loss-of-function mutants were found to be more tolerant to iron-deficiency stress than wild type (WT) and to have higher iron and chlorophyll content. Further studies showed that the transcriptional levels of iron-uptake related genes IRT1, FRO2, AHA2, FIT and bHLH38 in mutants were significantly higher than in WT under iron deficiency. Comparative transcriptome analysis suggested that the differentially expressed genes (DEGs) between ERF96-loss-of-function mutant and WT under iron deficiency were mainly enriched in iron uptake and chlorophyll degradation. According to the specific analysis of these two kinds of DEGs, the expression of iron uptake and transport related genes in ERF96-loss-of-function mutant was higher and the expression of chlorophyll degradation related genes was lower under iron deficiency. Furthermore, loss-of-function of ERF96 influenced the plant hormone, especially auxin and ethylene signal transduction. Altogether, our results demonstrate that loss-of-function of ERF96 increased Fe uptake and chlorophyll level through ethylene and auxin signal pathway in the regulation of iron-deficiency response in Arabidopsis.
查看更多>>摘要：Root border cells (RBCs) and their mucilage are considered to play an important role in protecting root tip from aluminum (Al) toxicity, but their interactions with silicon (Si) under Al stress still remain unclear. Here, we investigated the effect of Si on the formation of RBCs under Al stress and the related detoxification mechanism in hydroponically grown rice (Oryza sativa L.). The results showed that Si could prevent the separation of RBCs from each other by increasing the degree of pectin methylesterification in root tip cell wall, thereby keeping more RBCs around the root tip. Also, Si maintained the viability of RBCs, increased the amount of mucilage, and reduced the content of total Al and free Al in root tips. Moreover, the RBCs accumulated more Al and Si simultaneously than root tip in the Al treatments with Si supply. Overall, these results indicated that Si reduced the toxicity of Al to RBCs through formation of Si-Al complex on the RBCs, thereby improving the viability of RBCs and promoting the secretion of mucilage. Concomitantly, Si, RBCs and their mucilage could form a protective sheath at the root tip, which prevented Al from diffusing into the root tip, thereby alleviating Al toxicity in rice root tips.
查看更多>>摘要：Soybean germination under ultraviolet-B (UV-B) radiation stress is a common and effective way to enrich the isoflavone content of sprouts. However, the growth and biomass of germinated soybeans are significantly suppressed using this method. Melatonin (MT), a novel plant biostimulant, not only plays a vital protective role in responses to various abiotic stresses but also regulates the accumulation of secondary metabolites. In the present study, the effects of exogenous MT on the growth and isoflavone metabolism of germinating soybeans exposed to UV-B stress were investigated. Compared to UV-B stress, the application of exogenous MT (25 mu M) significantly increased sprout length, fresh weight, Ca2+ influx, and peroxidase activity; markedly decreased the content of malondialdehyde and H2O2 and the fluorescence intensity of H2O2 and O-2(center dot)-; but had no noticeable effect on the activity of superoxide dismutase and catalase during germination. Moreover, the content of total flavonoids and isoflavone monomers (including daidzein, genistein, daidzin, glycitin and genistin) in 4-day-old germinated soybeans was significantly enhanced by MT application under UV-B stress and was not only companied by dramatically increased phenylalanine ammonia lyase activity, but also by markedly increased relative expression levels of phenylalanine ammonia lyase1, chalcone synthase , isoflavone reductase and flavanone 3-hydroxylase that are involved in the isoflavone biosynthesis pathway. The inhibitory effects of UV-B stress on the growth and biomass of germinated soybeans were alleviated with exogenous MT. MT enhanced the content of total flavonoids and isoflavone monomers under UV-B stress by increasing the activity and relative gene expression level of critical isoflavone biosynthesis-related enzymes.
Mininni, Alba N. N.Tuzio, Angelo C. C.Brugnoli, EnricoDichio, Bartolomeo...
11页
查看更多>>摘要：In C-3 plants, carbon isotope composition (delta C-13) is influenced by isotopic effects during diffusion from the atmosphere to the chloroplasts and carboxylation reactions. This work aimed to demonstrate if delta C-13 of leaf soluble carbohydrates (delta C-13(leaves)) and of dry matter from new-growth shoots (delta C-13(shoots)) of Prunus plants subjected to a period of water deficit was related to water use efficiency (WUE). For this purpose, three interspecific Prunus hybrids rootstocks (6-5, 7-7 and G x N) were gradually subjected to drought and then rewatered. Soil water content (SWC) decreased from 26.1 to 9.4% after 70 days of water shortage, when plants reached values of predawn leaf water potential (LWP) ranging from-3.12 to-4.00 MPa. Gas exchange, particularly net photo-synthetic and transpiration rates, differed among the three hybrids, leading to different values of WUE. After 70 days of drought, a significant delta C-13 increase of 5.86, 4.28 and 4.99 parts per thousand was observed in 6-5, 7-7 and G x N, respectively. Significant correlations between 813C and other parameters (substomatal CO2/atmospheric CO2 ratio, stomatal conductance and stem water potential) were found in all hybrids. The rewatering phase caused a recovery of the physiological status of the plants. The isotope composition of delta C-13 (shoots) was correlated with the average WUE measured during the whole experiment. delta C-13(leaves) and delta C-13(shoots) were positively related (r = 0.87; p < 0.001). The isotopic signature was a reliable screening tool to identify Prunus genotypes tolerant to drought stress. The results suggest the possibility of using delta C-13 as an integrated indicator of level of drought stress in plants subjected to prolonged stress conditions.
查看更多>>摘要：The negative impact of the misuse of antibiotics on agriculture and human health has become a popular research topic with the increasing usage of antibiotics; however, little information is available about the mechanisms of OFL (ofloxacin) and Si (silicon). In this experiment, we applied 7 OFL concentrations to two Chinese cabbage cultivars (Qinghua and Biyu) to screen proper OFL concentrations. OFL concentrations of 0, 1, 2.5 and 5 mg L-1 were selected for the subsequent test and 1.2 mmol L-1 Si was used as mitigation. The results showed that Biyu suffered more damage than Qinghua and the injury degree increased in a concentration-dependent manner. With increasing OFL concentrations, the photosynthetic fluorescence was weakened significantly; under 1, 2.5 and 5 mg L-1 OFL, the Pn reduced by 5.35%, 35.92% and 43.62% in Qinghua and 33.98%, 41.94% and 64.66% in Biyu, respectively. The production rate of O-2- , H2O2 and the MDA content were increased and Biyu appeared higher increase rates. In addition, the antioxidant enzymes contents first increased and then decreased and that of Qinghua increased more than Biyu. Si ensured the growth under OFL and protected its photosynthetic ability. Under the OFL1+Si, OFL2.5 + Si and OFL5+Si treatments, Pn increased by 3.91%, 15.95 and 15.69% in Qinghua and 28.82%, 20.40% and 39.01% in Biyu. Si also maintained the structural integrity of leaf organelles and improved the scavenging ability of ROS by increasing the activity and relative gene expression of antioxidant enzymes. Moreover, varietal differences may play a more important role than Si.
查看更多>>摘要：Saline-alkaline stress inhibits plant growth and reduces yield. Abscisic acid (ABA) is an important plant hormone in response to plant stress. However, the role of ABA under saline-alkaline stress is poorly understood. Therefore, the mechanisms of ABA accumulation and resistance improvement in tomato seedlings were studied under saline-alkaline stress. We investigated whether ABA accumulation improved the saline-alkaline stress resistance ability of tomato. Here, wild-type (Solanum lycopersicum cv. Ailsa Craig) and ABA-deficient mutant (notabilis) seedlings were used to determine the membrane lipid peroxidation, osmotic substance and chlorophyll contents. ABA synthesis and signal transduction changes and ABA roles regulating the antioxidation in tomato seedlings subject to saline-alkaline stress were further explored. Results showed that ABA synthesis and signal trans-duction were induced by saline-alkaline stress. Under saline-alkaline stress, tomato seedlings had decreased relative water content, increased relative electrical conductivity and malondialdehyde content, and these changes were alleviated by exogenous ABA treatment. Exogenous ABA alleviated the degradation of chlorophyll in the leaves of tomato seedlings caused by saline-alkaline stress, further promoted the accumulation of proline and soluble sugar, reduced the content of ROS and improved the ability of the antioxidant enzyme system. Moreover, notabilis appeared to be sensitive to saline-alkaline stress. Overall, ABA is involved in the resistance of tomato seedlings to saline-alkaline stress, and exogenous ABA improves the saline-alkaline tolerance of tomato seedlings.
查看更多>>摘要：Heat shock transcription factors (Hsfs) are essential regulators of plant responses to abiotic stresses, growth, and development. However, all the Hsf family members have not been identified in Sorbus pohuashanensis. Therefore, the aim of this study was to identify the Hsf family members in S. pohuashanensis and examine their expression under abiotic stress conditions through the integration of gene structure, phylogenetic relationships, chromosome location, and expression patterns. Bioinformatics-based methods, identified 33 Hsfs in S. pohuashanensis. Phylogenetic analysis of Hsfs from S. pohuashanensis and other species revealed that they were more closely related to apples and white pears, followed by Populus trichocarpa, and most distantly related to Arabidopsis. Moreover, the Hsfs were clustered into three major groups: A, B, and C. Gene structure and conserved motif analysis revealed a high degree of conservation among members of the same class. Collinearity analysis revealed that segmental duplication played an essential role in increasing the size of the SpHsfs gene family in S. pohuashanensis. Additionally, several cis-acting elements associated with growth and development, hormone response, and stress were found in the promoter region of SpHsfs genes. Furthermore, expression analysis in various tissues of S. pohuashanensis showed that the genes were closely associated with heat, drought, salt stress, growth, and developmental processes. Overall, these results provide valuable information on the evolutionary relationships of the Hsf gene family. These genes stand as strong functional candidates for further studies on the resistance of S. pohuashanensis to abiotic stresses.
NSTL
Elsevier