The NAC (NAM, ATAF1/2, and CUC2) transcription factors comprise one of the largest transcription factor families in plants and play important roles in stress responses. However, little is known about ...the functions of potato NAC family members. Here we report the cloning of a potato NAC transcription factor gene
, which was significantly upregulated after salt, drought, and abscisic acid treatments. Furthermore, the StNAC053-GFP fusion protein was found to be located in the nucleus and had a C-terminal transactivation domain, implying that StNAC053 may function as a transcriptional activator in potato. Notably,
plants overexpressing
displayed lower seed germination rates compared to wild-type under exogenous ABA treatment. In addition, the
overexpression
lines displayed significantly increased tolerance to salt and drought stress treatments. Moreover, the
lines were found to have higher activities of superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) under multiple stress treatments. Interestingly, the expression levels of several stress-related genes including
,
,
,
, and
, were significantly upregulated in these
-overexpressing lines. Taken together, overexpression of the stress-inducible
gene could enhance the tolerances to both salt and drought stress treatments in
, likely by upregulating stress-related genes.
NAC proteins constitute one of the largest transcription factor families and are involved in regulation of plant development and stress responses. Our previous transcriptome analyses of tobacco ...revealed a significant increase in the expression of
NtNAC028
during leaf yellowing. In this study, we found that
NtNAC028
was rapidly upregulated in response to high salinity, dehydration, and abscisic acid (ABA) stresses, suggesting a vital role of this gene in abiotic stress response.
NtNAC028
loss-of-function tobacco plants generated
via
CRISPR-Cas9 showed delayed leaf senescence and increased tolerance to drought and salt stresses. Meanwhile
NtNAC028
overexpression led to precocious leaf senescence and hypersensitivity to abiotic stresses in
Arabidopsis
, indicating that
NtNAC028
functions as a positive regulator of natural leaf senescence and a negative regulator of stress tolerance. Furthermore,
NtNAC028
-overexpressing
Arabidopsis
plants showed lower antioxidant enzyme activities, higher reactive oxygen species (ROS), and H
2
O
2
accumulation under high salinity, resulted in more severe oxidative damage after salt stress treatments. On the other hand,
NtNAC028
mutation in tobacco resulted in upregulated expression of ROS-scavenging and abiotic stress-related genes, higher antioxidant enzyme activities, and enhanced tolerance against abiotic stresses, suggesting that
NtNAC028
might act as a vital regulator for plant stress response likely by mediating ROS scavenging ability. Collectively, our results indicated that the
NtNAC028
plays a key regulatory role in leaf senescence and response to multiple abiotic stresses.
Leaf senescence is a highly coordinated process and has a significant impact on agriculture. Plant peptides are known to act as important cell-to-cell communication signals that are involved in ...multiple biological processes such as development and stress responses. However, very limited number of peptides has been reported to be associated with leaf senescence. Here, we report the characterization of the INFLORESCENCE DEFICIENT IN ABSCISSION-LIKE6 (IDL6) peptide as a regulator of leaf senescence. The expression of
IDL6
was up-regulated in senescing leaves. Exogenous application of synthetic IDL6 peptides accelerated the process of leaf senescence. The
idl6
mutant plants showed delayed natural leaf senescence as well as senescence included by darkness, indicating a regulatory role of IDL6 peptides in leaf senescence. The role of IDL6 as a positive regulator of leaf senescence was further supported by the results of overexpression analysis and complementation test. Transcriptome analysis revealed differential expression of phytohormone-responsive genes in
idl6
mutant plants. Further analysis indicated that altered expression of IDL6 led to changes in leaf senescence phenotypes induced by ABA and ethylene treatments. The results from this study suggest that the IDL6 peptide positively regulates leaf senescence in
Arabidopsis thaliana
.
The CLE family (CLAVATA3/embryo surrounding region-related), a class of small secreted proteins, play important roles in plant development and stress responses. Members of the CLE family have been ...characterized in a number of plant species, including Arabidopsis and rice. However, limited information is available about CLE peptides in tobacco (Nicotiana tabacum) and related Nicotiana species. Here we report the identification of 84 CLE family members in three Nicotiana species based on sequence similarity. The newly identified CLE members, including 41 from N. tabacum, 19 from N. sylvestris, and 24 from N. tomentosiformis, together with 32 CLEs from Arabidopsis and 52 CLEs from tomato, formed 9 subgroups in a phylogenic tree. The unbalanced distribution of the Nicotiana CLEs in the subgroups suggested potential preferential gene family expansion during evolution. Expression of the NtCLE genes was analyzed and a number of the NtCLEs showed induced expression upon abiotic stress treatments. Synthetic peptides of several NtCLEs, when applied to detached tobacco leaf discs, were able to increase plants’ tolerance to osmotic and salinity stresses, suggesting potential roles of CLE peptides in the stress responses of tobacco.
•Four proso millet grains with different color were subject to metabolomic analysis.•There are more than 100 differential metabolites between white and colored grains.•Colored grains have higher ...phenolic acid and flavonoid contents than white grains.•Levels of amino acids are significantly different among the four varieties.
Proso millet (Panicum miliaceum L.) is a minor cereal crop that has been considered as health-promoting food. Little information is available however, about the metabolic basis of nutritional values of proso millet. In this study, using a UHPLC-QqQ-MS/MS-based metabolomics approach, we compared the metabolomes of whole grains from four proso millet varieties with different bran color, namely White, Black, Gray and Red. In total, 672 metabolites were identified, among which 121, 116 and 148 metabolites showed differential accumulation in the three comparison groups (White vs. Black/Gray/Red). The results demonstrated the main pathways that were differentially activated included: tryptophan metabolism, flavonoid, isoflavonoid, flavone, and flavonol biosynthesis. Considerable difference between varieties was observed in accumulation of phenolic acids and flavonoids, which might lead to difference in antioxidant activities. The results of this study provide useful information for further investigation of proso millet food chemistry and for sufficient utilization of this special crop.
Abstract
Receptor-like kinases (RLKs) are the most important class of cell surface receptors, and play crucial roles in plant development and stress responses. However, few studies have been reported ...about the biofunctions of RLKs in leaf senescence. Here, we characterized a novel Arabidopsis RLK-encoding gene, SENESCENCE-RELATED RECEPTOR KINASE 1 (SENRK1), which was significantly down-regulated during leaf senescence. Notably, the loss-of-function senrk1 mutants displayed an early leaf senescence phenotype, while overexpression of SENRK1 significantly delayed leaf senescence, indicating that SENRK1 negatively regulates age-dependent leaf senescence in Arabidopsis. Furthermore, the senescence-promoting transcription factor WRKY53 repressed the expression of SENRK1. While the wrky53 mutant showed a delayed senescence phenotype as previously reported, the wrky53 senrk1-1 double mutant exhibited precocious leaf senescence, suggesting that SENRK1 functions downstream of WRKY53 in regulating age-dependent leaf senescence in Arabidopsis.
The LRR-RLK protein SENRK1 functions downstream of WRKY53 in regulating age-dependent leaf senescence, in which WRKY53 is a positive regulator, while SENRK1 is a negative regulator.
The CLE family (CLAVATA3/embryo surrounding region-related), a class of small secreted proteins, play important roles in plant development and stress responses. Members of the CLE family have been ...characterized in a number of plant species, including Arabidopsis and rice. However, limited information is available about CLE peptides in tobacco (Nicotiana tabacum) and related Nicotiana species. Here we report the identification of 84 CLE family members in three Nicotiana species based on sequence similarity. The newly identified CLE members, including 41 from N. tabacum, 19 from N. sylvestris, and 24 from N. tomentosiformis, together with 32 CLEs from Arabidopsis and 52 CLEs from tomato, formed 9 subgroups in a phylogenic tree. The unbalanced distribution of the Nicotiana CLEs in the subgroups suggested potential preferential gene family expansion during evolution. Expression of the NtCLE genes was analyzed and a number of the NtCLEs showed induced expression upon abiotic stress treatments. Synthetic peptides of several NtCLEs, when applied to detached tobacco leaf discs, were able to increase plants' tolerance to osmotic and salinity stresses, suggesting potential roles of CLE peptides in the stress responses of tobacco.
Mode analysis method based on finite element theory is proposed to plot dispersion curves in metal sheet. This method is implemented by adopting COMSOL software to numerically solve and plot the ...dispersion curves. Compared with results obtained by semi-analytical finite element method, the calculating results are basically consistent and the modal caused by mode blending is obtained, which proves the mode analysis method is effective. Finally, the wave structure characteristics of various models are analysed, this provides a basis for the application of ultrasonic guided wave testing.
Aiming at the thickness detection of the plate surface attachment, a nondestructive testing method based on the Lamb wave is presented. This method utilizes Lamb wave propagation characteristics of ...signals in a bi-layer medium to measure the surface attachment plate thickness. Propagation of Lamb wave in bi-layer elastic is modeled and analyzed. The two-dimensional simulation model of electromagnetic ultrasonic plate - scale is established. The simulation is conducted by software COMSOL for simulation analysis under different boiler scale thickness wave form curve. Through this study, the thickness of the attached material can be judged by analyzing the characteristics of the received signal when the thickness of the surface of the plate is measured.
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