Research progress of the Elongator complex in plant

The Elongator complex consists of six subunits (ELP1-ELP6), where ELP1-ELP3 forms the core subcomplex and ELP4-ELP6 forms the auxiliary subcomplex. Deletion of any of the six subunits results in an almost identical phenotype, suggesting that all six subunits are essential for cellular function. All six subunits are evolutionarily conserved in terms of sequence and their interactions with other subunits. The most striking features are the structural conservation of the protein complexes and the phenotypic similarity caused by loss-of-function mutations in any protein subunit. Similar to elongation factors in translation, there is a strong interaction between the Elongator complex and RNA polymerase II during transcription. The Elongator complex is also involved in a variety of cellular pathways, including histone modification/acetylation, DNA methylation, tRNA nucleoside modification, etc. Here, we summarized the functions and mechanisms of the Elongator complex in plant growth and development, molecular pathways, and gene regulation. In this way, we aimed to provide a reference for an in-depth study of the Elongator complex

Integrated Transcriptome and Proteome Analyses of Maize Inbred lines in Response to Salt Stress

To better understand the resistance of maize (Zea mays L.) to salt stress, maize inbred lines 8723 and P138, which are salt-tolerant and salt-sensitive, respectively, were investigated using the transcriptional and proteomic profiling of seedling roots under normal conditions and 180 mM NaCl stress. The screening criteria for differentially expressed proteins (DEPs) were a fold change (FC) ≥1.20 (up-regulated) or ≤0.83 (down-regulated). Additionally, the screening criteria for differentially expressed genes (DEGs) were FC >2 or <0.5. We analyzed the correlation between the protein and mRNA levels of two maize inbred lines under salt stress and found that a total of 3152 associated genes/proteins were identified in line 8723 under salt stress. However, only 14 DEGs were also identified by their corresponding DEPs, with a correlation coefficient of 0.07. A similar comparison of the 3159 genes/proteins affected by salt stress in line P138 identified just 8 DEGs with corresponding DEPs, with a correlation coefficient of 0.05. This indicates major differences in the regulation of transcriptional and translational processes in response to salt stress. In addition, in line 8723, we identified just eight DEGs with the same expression trend as their corresponding DEPs and six DEGs that behaved in contrast to their DEPs under salt stress. Compared to P138, the root response to salt stress in line 8723 involved the following processes. First, the up-regulation of lipid transporters and the lipid transfer-like protein VAS resulted in an increased lipid metabolism. Next, the increased expression of CAD6, as well as PRP1 and PRP10 under salt stress, promoted lignin synthesis and activated the abscisic acid signal pathway, respectively. In addition, the up-regulation of ADK2 and adenylate kinase expression regulated the concentration of purine ribonucleoside to help maintain dynamic energy balance in the maize cells. Furthermore, reactive oxygen species (ROS) scavenging and protective mechanisms were effectively enhanced by the up-regulation of peroxidase 12, peroxidase 67, glutathione transferase 9 and the putative laccase family protein, and the down-regulation of peroxidase 72. Therefore, maize enhances its salt tolerance by enhancing its lipid metabolism, promoting lignin biosynthesis, activating the abscisic acid signaling pathway, maintaining the dynamic energy balance of the maize cells, and enhancing the ROS clearance and protection mechanisms. Our study identified some genes and proteins related to salt tolerance in maize, and has thus provided new and important clues to better understand the resistance of maize to salt stress

Integrated Transcriptome and Proteome Analyses of Maize Inbred lines in Response to Salt Stress

To better understand the resistance of maize (Zea mays L.) to salt stress, maize inbred lines 8723 and P138, which are salt-tolerant and salt-sensitive, respectively, were investigated using the transcriptional and proteomic profiling of seedling roots under normal conditions and 180 mM NaCl stress. The screening criteria for differentially expressed proteins (DEPs) were a fold change (FC) ≥1.20 (up-regulated) or ≤0.83 (down-regulated). Additionally, the screening criteria for differentially expressed genes (DEGs) were FC >2 or CAD6, as well as PRP1 and PRP10 under salt stress, promoted lignin synthesis and activated the abscisic acid signal pathway, respectively. In addition, the up-regulation of ADK2 and adenylate kinase expression regulated the concentration of purine ribonucleoside to help maintain dynamic energy balance in the maize cells. Furthermore, reactive oxygen species (ROS) scavenging and protective mechanisms were effectively enhanced by the up-regulation of peroxidase 12, peroxidase 67, glutathione transferase 9 and the putative laccase family protein, and the down-regulation of peroxidase 72. Therefore, maize enhances its salt tolerance by enhancing its lipid metabolism, promoting lignin biosynthesis, activating the abscisic acid signaling pathway, maintaining the dynamic energy balance of the maize cells, and enhancing the ROS clearance and protection mechanisms. Our study identified some genes and proteins related to salt tolerance in maize, and has thus provided new and important clues to better understand the resistance of maize to salt stress

The Mechanism of Exogenous Salicylic Acid and 6-Benzylaminopurine Regulating the Elongation of Maize Mesocotyl

The elongation of the mesocotyl plays an important role in the emergence of maize deep-sowing seeds. This study was designed to explore the function of exogenous salicylic acid (SA) and 6-benzylaminopurine (6-BA) in the growth of the maize mesocotyl and to examine its regulatory network. The results showed that the addition of 0.25 mmol/L exogenous SA promoted the elongation of maize mesocotyls under both 3 cm and 15 cm deep-sowing conditions. Conversely, the addition of 10 mg/L exogenous 6-BA inhibited the elongation of maize mesocotyls. Interestingly, the combined treatment of exogenous SA–6-BA also inhibited the elongation of maize mesocotyls. The longitudinal elongation of mesocotyl cells was the main reason affecting the elongation of maize mesocotyls. Transcriptome analysis showed that exogenous SA and 6-BA may interact in the hormone signaling regulatory network of mesocotyl elongation. The differential expression of genes related to auxin (IAA), jasmonic acid (JA), brassinosteroid (BR), cytokinin (CTK) and SA signaling pathways may be related to the regulation of exogenous SA and 6-BA on the growth of mesocotyls. In addition, five candidate genes that may regulate the length of mesocotyls were screened by Weighted Gene Co-Expression Network Analysis (WGCNA). These genes may be involved in the growth of maize mesocotyls through auxin-activated signaling pathways, transmembrane transport, methylation and redox processes. The results enhance our understanding of the plant hormone regulation of mesocotyl growth, which will help to further explore and identify the key genes affecting mesocotyl growth in plant hormone signaling regulatory networks

WGCNA analysis of the effect of exogenous BR on leaf angle of maize mutant lpa1

Abstract Leaf angle, as one of the important agronomic traits of maize, can directly affect the planting density of maize, thereby affecting its yield. Here we used the ZmLPA1 gene mutant lpa1 to study maize leaf angle and found that the lpa1 leaf angle changed significantly under exogenous brassinosteroid (BR) treatment compared with WT (inbred line B73). Transcriptome sequencing of WT and lpa1 treated with different concentrations of exogenous BR showed that the differentially expressed genes were upregulated with auxin, cytokinin and brassinosteroid; Genes associated with abscisic acid are down-regulated. The differentially expressed genes in WT and lpa1 by weighted gene co-expression network analysis (WGCNA) yielded two gene modules associated with maize leaf angle change under exogenous BR treatment. The results provide a new theory for the regulation of maize leaf angle by lpa1 and exogenous BR

Series Expansion for Direct and Inverse Solutions of Meridian in Terms of Different Latitude Variables

Formulas for direct solutions of meridian written by the reduced and geocentric latitudes respectively were derived by series expansion. Meanwhile, according to Lagrange inversion theorem, formulas for inverse solutions of the issue were also expressed in terms of the same latitudes. These two formulas were structurally consistent with that expressed by geodetic latitude ones. In these sets of formulas, internal connection between meridian and three different types of latitude were realized. Analysis and numerical calculation showed that the direct and inverse meridional solution with reduced latitude was of higher precision than that with geodetic latitude, and furthermore, there had a unified theory between meridian theory and classical geodetic problems expressed by reduced latitude

Transcriptome-Based Weighted Correlation Network Analysis of Maize Leaf Angle Regulation by Exogenous Brassinosteroid

Maize (Zea mays L.) leaf angle is an important characteristic affecting high-density planting, and it is also a central indicator for maize plant type selection to improve yield. Brassinosteroids (BRs) are a class of phytohormones that could modulate the growth and development of plant leaf angles. However, its functional mechanism remains unclear in maize. In this study, we used maize self-line B73 as material to analyze the transcriptome of leaf cushion after BR treatment at the seedling stage. Using seven concentrations of exogenous BR-treated maize B73 plants, the results show that the leaf angle and the cell length near the leaf pillow increased and then decreased with BR concentration increasing, and the 50 μM level was the best treatment. Analysis of 11,487 differences expressed genes (DEGs) found that genes related to cell volume were up-regulated, and the expression of genes related to the cell division was down-regulated. It is speculated that exogenous BR regulates the size of the maize leaf angle by regulating cell volume and cell division, and so we constructed a molecular mechanism model of maize response to exogenous BR. The molecular mechanism model of exogenous BR through weighted gene co-expression network analysis (WGCNA) DEGs, and two gene modules related to changes in maize leaf angle were identified. The results can provide a theoretical basis for determining the mechanism of exogenous BR-regulated maize

Transcriptome-Based Weighted Correlation Network Analysis of Maize Leaf Angle Regulation by Exogenous Brassinosteroid

Maize (Zea mays L.) leaf angle is an important characteristic affecting high-density planting, and it is also a central indicator for maize plant type selection to improve yield. Brassinosteroids (BRs) are a class of phytohormones that could modulate the growth and development of plant leaf angles. However, its functional mechanism remains unclear in maize. In this study, we used maize self-line B73 as material to analyze the transcriptome of leaf cushion after BR treatment at the seedling stage. Using seven concentrations of exogenous BR-treated maize B73 plants, the results show that the leaf angle and the cell length near the leaf pillow increased and then decreased with BR concentration increasing, and the 50 μM level was the best treatment. Analysis of 11,487 differences expressed genes (DEGs) found that genes related to cell volume were up-regulated, and the expression of genes related to the cell division was down-regulated. It is speculated that exogenous BR regulates the size of the maize leaf angle by regulating cell volume and cell division, and so we constructed a molecular mechanism model of maize response to exogenous BR. The molecular mechanism model of exogenous BR through weighted gene co-expression network analysis (WGCNA) DEGs, and two gene modules related to changes in maize leaf angle were identified. The results can provide a theoretical basis for determining the mechanism of exogenous BR-regulated maize

Comparing transcriptome expression profiles to reveal the mechanisms of salt tolerance and exogenous glycine betaine mitigation in maize seedlings.

Salt stress is a common abiotic stress that limits the growth, development and yield of maize (Zea mays L.). To better understand the response of maize to salt stress and the mechanism by which exogenous glycine betaine (GB) alleviates the damaging effects of salt stress, the morphology, physiological and biochemical indexes, and root transcriptome expression profiles of seedlings of salt-sensitive inbred line P138 and salt-tolerant inbred line 8723 were compared under salt stress and GB-alleviated salt stress conditions. The results showed that under salt stress the growth of P138 was significantly inhibited and the vivo ion balance was disrupted, whereas 8723 could prevent salt injury by maintaining a high ratio of K+ to Na+. The addition of a suitable concentration of GB could effectively alleviate the damage caused by salt stress, and the mitigating effect on salt-sensitive inbred line P138 was more obvious than that on 8723. Transcriptome analysis revealed that 219 differentially expressed genes (DEGs) were up-regulated and 153 DEGs were down-regulated in both P138 and 8723 under NaCl treatment, and that 487 DEGs were up-regulated and 942 DEGs were down-regulated in both P138 and 8723 under salt plus exogenous GB treatment. In 8723 the response to salt stress is mainly achieved through stabilizing ion homeostasis, strong signal transduction activation, increasing reactive oxygen scavenging. GB alleviates salt stress in maize mainly by inducing gene expression changes to enhance the ion balance, secondary metabolic level, reactive oxygen scavenging mechanism, signal transduction activation. In addition, the transcription factors involved in the regulation of salt stress response and exogenous GB mitigation mainly belong to the MYB, MYB-related, AP2-EREBP, bHLH, and NAC families. We verified 10 selected up-regulated DEGs by quantitative real-time polymerase chain reaction (qRT-PCR), and the expression results were basically consistent with the transcriptome expression profiles. Our results from this study may provide the theoretical basis for determining maize salt tolerance mechanisms and the mechanism by which GB regulates salt tolerance

Mutant lpa1 Analysis of ZmLPA1 Gene Regulates Maize Leaf-Angle Development through the Auxin Pathway

Maize plant type is one of the main factors determining maize yield, and leaf angle is an important aspect of plant type. The rice Loose Plant Architecture1 (LPA1) gene and Arabidopsis AtIDD15/SHOOT GRAVITROPISM5 (SGR5) gene are related to their leaf angle. However, the homologous ZmLPA1 in maize has not been studied. In this study, the changing of leaf angle, as well as gene expression in leaves in maize mutant lpa1 and wild-type ‘B73’ under different IAA concentrations were investigated. The regulation effect of IAA on the leaf angle of lpa1 was significantly stronger than that of the wild type. Transcriptome analysis showed that different exogenous IAA treatments had a common enrichment pathway—the indole alkaloid biosynthesis pathway—and among the differentially expressed genes, four genes—AUX1, AUX/IAA, ARF and SAUR—were significantly upregulated. This study revealed the regulation mechanism of ZmLPA1 gene on maize leaf angle and provided a promising gene resource for maize breeding