Nanoselenium transformation and inhibition of cadmium accumulation by regulating the lignin biosynthetic pathway and plant hormone signal transduction in pepper plants

Selenium (Se) can promote the growth and resistance of agricultural crops as fertilizers, while the role of nano-selenium (nano-Se) against Cd remains unclear in pepper plants (Capsicum annuum L.). Biofortification with nano-Se observably restored Cd stress by decreasing the level of Cd in plant tissues and boosting the accumulation in biomass. The Se compounds transformed by nano-Se were primarily in the form of SeMet and MeSeCys in pepper tissues. Differential metabolites and the genes of plant signal transduction and lignin biosynthesis were measured by employing transcriptomics and determining target metabolites. The number of lignin-related genes (PAL, CAD, 4CL, and COMT) and contents of metabolites (sinapyl alcohol, phenylalanine, p-coumaryl alcohol, caffeyl alcohol, and coniferaldehyde) were remarkably enhanced by treatment with Cd1Se0.2, thus, maintaining the integrity of cell walls in the roots. It also enhanced signal transduction by plant hormones and responsive resistance by inducing the biosynthesis of genes (BZR1, LOX3, and NCDE1) and metabolites (brassinolide, abscisic acid, and jasmonic acid) in the roots and leaves. In general, this study can enable a better understanding of the protective mechanism of nano-Se in improving the capacity of plants to resist environmental stress.

Nanoselenium Transformation And Inhibition of Cadmium Accumulation By Regulating The Lignin Biosynthetic Pathway And Plant Hormone Signal Transduction In Pepper Plants

Selenium (Se) can promote the growth and resistance of agricultural crops as fertilizers, while the role of nano-selenium (nano-Se) against Cd remains unclear in pepper plants (Capsicum annuum L.). Biofortification with nano-Se observably restored Cd stress by decreasing the level of Cd in plant tissues and boosting the accumulation in biomass. The Se compounds transformed by nano-Se were primarily in the form of SeMet and MeSeCys in pepper tissues. Differential metabolites and the genes of plant signal transduction and lignin biosynthesis were measured by employing transcriptomics and determining target metabolites. The number of lignin-related genes (PAL, CAD, 4CL, and COMT) and contents of metabolites (sinapyl alcohol, phenylalanine, p-coumaryl alcohol, caffeyl alcohol, and coniferaldehyde) were remarkably enhanced by treatment with Cd1Se0.2, thus, maintaining the integrity of cell walls in the roots. It also enhanced signal transduction by plant hormones and responsive resistance by inducing the biosynthesis of genes (BZR1, LOX3, and NCDE1) and metabolites (brassinolide, abscisic acid, and jasmonic acid) in the roots and leaves. In general, this study can enable a better understanding of the protective mechanism of nano-Se in improving the capacity of plants to resist environmental stress.

Identification and Characterization of Abiotic Stress Responsive CBL-CIPK Family Genes in Medicago

The calcineurin B-like protein (CBL) and CBL-interacting protein kinase (CIPK) play important roles in plant signal transduction and response to abiotic stress. Plants of Medicago genus contain many important forages, and their growth is often affected by a variety of abiotic stresses. However, studies on the CBL and CIPK family member and their function are rare in Medicago. In this study, a total of 23 CBL and 58 CIPK genes were identified from the genome of Medicago sativa as an important forage crop, and Medicaog truncatula as the model plant. Phylogenetic analysis suggested that these CBL and CIPK genes could be classified into five and seven groups, respectively. Moreover, these genes/proteins showed diverse exon-intron organizations, architectures of conserved protein motifs. Many stress-related cis-acting elements were found in their promoter region. In addition, transcriptional analyses showed that these CBL and CIPK genes exhibited distinct expression patterns in various tissues, and in response to drought, salt, and abscisic acid treatments. In particular, the expression levels of MtCIPK2 (MsCIPK3), MtCIPK17 (MsCIPK11), and MtCIPK18 (MsCIPK12) were significantly increased under PEG, NaCl, and ABA treatments. Collectively, our study suggested that CBL and CIPK genes play crucial roles in response to various abiotic stresses in Medicago.

Morphological Physiological and Transcriptional Response to Low Nitrogen Stress in Populus Deltoides Marsh. Clones With Contrasting Nitrogen Use Efficiency

Background: Nitrogen (N) is one of the main factors limiting the wood yield in poplar cultivation. Understanding the molecular mechanism of N utilization could play a guiding role in improving the nitrogen use efficiency (NUE). Results: In this study, three N-efficient genotypes (A) and three N-inefficient genotypes (C) of Populus deltoides were cultured under low N stress (5 μM NH4NO3) and normal N supply (750 μM NH4NO3). The dry matter mass, leaf morphology, and chlorophyll content of both genotypes decreased under N starvation. Interestingly, N starvation induced fine root growth in A, but not in C. Next, a detailed time-course analysis of enzyme activities and gene expression in leaves identified 2,062 differentially expressed genes (DEGs) in A and 1,118 in C, most of which were up-regulated. Moreover, the sensitivity to N starvation of A was weak, and DEGs related to hormone signal transduction played an important role in the low N response in A. The weighted gene co-expression network analysis identified genes related to membrane, catalytic activity, enzymatic activity, and response to stresses might be critical for poplar’s adaption to N starvation and these genes participated in the negative regulation of various biological processes. Finally, ten influential hub genes and twelve transcription factors were identified in the response to N starvation, among them Podel.19G001200, Podel.19G035300, Podel.02G021400, and Podel.04G076900 were related to programmed cell death, and the defense response, and PodelWRKY41, PodelWRKY75, PodelWRKY18, PodelBHLH25, PodelBHLH30, PodelBHLH, and PodelHY5 were involved in plant signal transduction.Conclusions: Under the condition of N starvation, A showed stronger adaptability and a better NUE than C in morphology and physiology. The discovery of hub genes and TFs provided a new information for the analysis of the molecular mechanism of N efficient utilization and the improvement of NUE of poplar.

Interaction between the Lentil Lipid Transfer Protein Lc-LTP2 and Its Novel Signal Ligand PI(4,5)P2

It is known that plant lipid transfer proteins (LTPs) bind a broad spectrum of ligands including fatty acids (FAs), phospho- and glycolipids, acyl-coenzyme A and secondary metabolites. In this work, we used protein−lipid overlay assays to identify new putative LTP ligands. In our experiments, the lentil lipid transfer protein Lc-LTP2 as well as LTPs from other plants were shown to bind phosphatidylinositol (4,5)-bisphosphate (PI(4,5)P2). Molecular modeling, 2-p-toluidinonaphthalene-6-sulphonate (TNS) displacement and liposome leakage experiments with Lc-LTP2 and its mutant analogs (R45A, Y80A, R45A/Y80A) were performed to investigate interactions between the protein and PI(4,5)P2. It was shown that PI(4,5)P2 initially interacted with the “bottom” entrance of the protein cavity and after complex formation the large polar head of this ligand was also oriented towards the same entrance. We also found that two highly conserved residues in plant LTPs, Arg45 and Tyr80, played an important role in protein-ligand interactions. Apparently, Arg45 is a key residue for interaction with PI(4,5)P2 during both initial contacting and holding in the protein cavity, while Tyr80 is probably a key amino acid playing an essential role in Lc-LTP2 docking to the membrane. Thus, we assumed that the ability of Lc-LTP2 to bind PI(4,5)P2 suggests the involvement of this protein in plant signal transduction.

Transcriptome-Wide Identification, Evolutionary Analysis, and GA Stress Response of the GRAS Gene Family in Panax ginseng C. A. Meyer

GRAS transcription factors are a kind of plant-specific transcription factor that have been found in a variety of plants. According to previous studies, GRAS proteins are widely involved in the physiological processes of plant signal transduction, stress, growth and development. The Jilin ginseng (Panax ginseng C.A. Meyer) is a heterogeneous tetraploid perennial herb of the Araliaceae family, ginseng genus. Important information regarding the GRAS transcription factors has not been reported in ginseng. In this study, 59 Panax ginseng GRAS (PgGRAS) genes were obtained from the Jilin ginseng transcriptome data and divided into 13 sub-families according to the classification of Arabidopsis thaliana. Through systematic evolution, structural variation, function and gene expression analysis, we further reveal GRAS’s potential function in plant growth processes and its stress response. The expression of PgGRAS genes responding to gibberellin acids (GAs) suggests that these genes could be activated after application concentration of GA. The qPCR analysis result shows that four PgGRAS genes belonging to the DELLA sub-family potentially have important roles in the GA stress response of ginseng hairy roots. This study provides not only a preliminary exploration of the potential functions of the GRAS genes in ginseng, but also valuable data for further exploration of the candidate PgGRAS genes of GA signaling in Jilin ginseng, especially their roles in ginseng hairy root development and GA stress response.

Ethylene signaling transcription factor promote grape growth induced by exogenous carbon

Background The carbon can be converted into sugar which is not only important for plant growth and development, but also for plant signal transduction, especially in plant hormone response. The objective of this work was to build available genomic and proteomic resource to investigate the molecular mechanisms of exogenous carbon regulating plant growth and development. Results Grape (Vitis vinifera L. cv. ‘Pinot Noir’) plantlets cultured with exogenous carbon (2% sucrose, 1000 μmol·mol-1 CO2 and with both 2% sucrose and 1000 μmol·mol-1 CO2 were designated as S1, C0 and Cs, respectively). We used S0 (without sucrose, ambient CO2) as CK to analyze the differential expression genes and proteins induced by exogenous carbon. Through the transcriptomic and proteomic analysis, with pooled data for Cs, C0 and S1 compared with CK, 70 differentially expressed genes (DEGs) and 65 differentially expressed proteins (DEPs) were identified. Based on biological functions and physiological characteristics, we identified 8 DEGs and 2 DEPs related to ethylene signaling process. Amongst the DEGs we focussed on ERF TFs, including ERF5 (LOC100244353, LOC100247763, LOC100254616 and LOC100261260), ERF105 (LOC100249507 and LOC100259725), ERF2 (LOC100254640) and CTr (CTr7). Also, there were 2 DEPs related to ethylene metabolism, such as S-adenosylmethionine synthase 5 (SAM synthase 5; XP_002280106.1) and 1-aminocyclopropane-1-carboxylic acid oxidase 2 (ACC oxidase 2; NP_001267871.1) were also identified. The transcriptome and proteome results suggested that exogenous carbon inhibits ethylene biosynthesis through ACC oxidase 2. Additionally, CTr7 and ERF5, which were up-regulated, are related to the ethylene signaling pathway. We speculate that exogenous carbon regulates plant growth through ethylene signaling pathways, but which inhibit ethylene biosynthesis. Conclusions Exogenous carbon regulates the expression of ethylene biosynthesis and signaling related genes, which may improve plant growth through the ethylene signaling pathway.

Identification of the GRAS gene family in the Brassica juncea genome provides insight into its role in stem swelling in stem mustard

GRAS transcription factors are known to play important roles in plant signal transduction and development. A comprehensive study was conducted to explore the GRAS family in the Brassica juncea genome. A total of 88 GRAS genes were identified which were categorized into nine groups according to the phylogenetic analysis. Gene structure analysis showed a high group-specificity, which corroborated the gene grouping results. The chromosome distribution and sequence analysis suggested that gene duplication events are vital for the expansion of GRAS genes in the B. juncea genome. The changes in evolution rates and amino acid properties among groups might be responsible for their functional divergence. Interaction networks and cis-regulatory elements were analyzed including DELLA and eight interaction proteins (including four GID1, two SLY1, and two PIF3 proteins) that are primarily involved in light and hormone signaling. To understand their regulatory role in growth and development, the expression profiles of BjuGRASs and interaction genes were examined based on transcriptome data and qRT-PCR, and selected genes (BjuGRAS3, 5, 7, 8, 10, BjuB006276, BjuB037910, and BjuA021658) had distinct temporal expression patterns during stem swelling, indicating that they possessed diverse regulatory functions during the developmental process. These results contribute to our understanding on the GRAS gene family and provide the basis for further investigations on the evolution and functional characterization of GRAS genes.