scholarly journals SmbHLH37 functions antagonistically with SmMYC2 in regulating jasmonate-mediated biosynthesis of phenolic acids in Salvia miltiorrhiza

2018 ◽  
Author(s):  
Tang-Zhi Du ◽  
Jun-Feng Niu ◽  
Jiao Su ◽  
Sha-Sha Li ◽  
Xiao-Rong Guo ◽  
...  
Keyword(s):  
Target Genes ◽  
Salvia Miltiorrhiza ◽  
Functional Characterization ◽  
Constitutive Expression ◽  
Defense Responses ◽  
Bhlh Transcription Factor ◽  
Bhlh Gene ◽  
Helix Loop Helix ◽  
Jaz Proteins ◽  
Ja Signaling

AbstractJasmonates (JAs) are integral to various defense responses and induce biosynthesis of many secondary metabolites. MYC2, a basic helix-loop-helix (bHLH) transcription factor (TF), acts as a transcriptional activator of JA signaling. MYC2 is repressed by the JASMONATE ZIM-domain (JAZ) proteins in the absence of JA, but de-repressed by the protein complex SCFCOI1 on perception of JA. We previously reported that overexpression of SmMYC2 promotes the production of salvianolic acid B (Sal B) in Salvia miltiorrhiza. However, the responsible molecular mechanism is unclear. Here, we showed that SmMYC2 binds to and activates the promoters of its target genes SmTAT1, SmPAL1, and SmCYP98A14 to activate Sal B accumulations. SmbHLH37, a novel bHLH gene significantly up-regulated by constitutive expression of SmMYC2, was isolated from S. miltiorrhiza for detailed functional characterization. SmbHLH37 forms a homodimer and interacts with SmJAZ3/8. Overexpression of SmbHLH37 substantially decreased yields of Sal B. SmbHLH37 binds to the promoters of its target genes SmTAT1 and SmPAL1 and blocks their expression to suppress the pathway for Sal B biosynthesis. These results indicate that SmbHLH37 negatively regulates JA signaling and functions antagonistically with SmMYC2 in regulating Sal B biosynthesis in S. miltiorrhiza.

scholarly journals Comprehensive Identification of PTI Suppressors in Type III Effector Repertoire Reveals that Ralstonia solanacearum Activates Jasmonate Signaling at Two Different Steps

2019 ◽  
Vol 20 (23) ◽  
pp. 5992 ◽  
Author(s):  
Masahito Nakano ◽  
Takafumi Mukaihara
Keyword(s):  
Pseudomonas Syringae ◽  
Cysteine Protease ◽  
Ralstonia Solanacearum ◽  
Acid Synthesis ◽  
Defense Responses ◽  
Dependent Manner ◽  
Jaz Proteins ◽  
Ros Burst ◽  
Ja Signaling ◽  
Activity Dependent

Ralstonia solanacearum is the causative agent of bacterial wilt in many plants. To identify R. solanacearum effectors that suppress pattern-triggered immunity (PTI) in plants, we transiently expressed R. solanacearum RS1000 effectors in Nicotiana benthamiana leaves and evaluated their ability to suppress the production of reactive oxygen species (ROS) triggered by flg22. Out of the 61 effectors tested, 11 strongly and five moderately suppressed the flg22-triggered ROS burst. Among them, RipE1 shared homology with the Pseudomonas syringae cysteine protease effector HopX1. By yeast two-hybrid screening, we identified jasmonate-ZIM-domain (JAZ) proteins, which are transcriptional repressors of the jasmonic acid (JA) signaling pathway in plants, as RipE1 interactors. RipE1 promoted the degradation of JAZ repressors and induced the expressions of JA-responsive genes in a cysteine–protease-activity-dependent manner. Simultaneously, RipE1, similarly to the previously identified JA-producing effector RipAL, decreased the expression level of the salicylic acid synthesis gene that is required for the defense responses against R. solanacearum. The undecuple mutant that lacks 11 effectors with a strong PTI suppression activity showed reduced growth of R. solanacearum in Nicotiana plants. These results indicate that R. solanacearum subverts plant PTI responses using multiple effectors and manipulates JA signaling at two different steps to promote infection.

scholarly journals Basic Helix-Loop-Helix (bHLH) Transcription Factors Regulate a Wide Range of Functions in Arabidopsis

2021 ◽  
Vol 22 (13) ◽  
pp. 7152
Author(s):  
Yaqi Hao ◽  
Xiumei Zong ◽  
Pan Ren ◽  
Yuqi Qian ◽  
Aigen Fu
Keyword(s):  
Transcription Factor ◽  
Transcription Factors ◽  
Target Genes ◽  
Gene Families ◽  
Bhlh Transcription Factor ◽  
Basic Helix Loop Helix ◽  
Helix Loop Helix ◽  
Wide Range ◽  
Range Of Functions ◽  
Eukaryotic Organisms

The basic helix-loop-helix (bHLH) transcription factor family is one of the largest transcription factor gene families in Arabidopsis thaliana, and contains a bHLH motif that is highly conserved throughout eukaryotic organisms. Members of this family have two conserved motifs, a basic DNA binding region and a helix-loop-helix (HLH) region. These proteins containing bHLH domain usually act as homo- or heterodimers to regulate the expression of their target genes, which are involved in many physiological processes and have a broad range of functions in biosynthesis, metabolism and transduction of plant hormones. Although there are a number of articles on different aspects to provide detailed information on this family in plants, an overall summary is not available. In this review, we summarize various aspects of related studies that provide an overview of insights into the pleiotropic regulatory roles of these transcription factors in plant growth and development, stress response, biochemical functions and the web of signaling networks. We then provide an overview of the functional profile of the bHLH family and the regulatory mechanisms of other proteins.

scholarly journals Genome-Wide Identification of the TIFY Family in Salvia miltiorrhiza Reveals That SmJAZ3 Interacts With SmWD40-170, a Relevant Protein That Modulates Secondary Metabolism and Development

2021 ◽  
Vol 12 ◽  
Author(s):  
Lin Li ◽  
Yuanchu Liu ◽  
Ying Huang ◽  
Bin Li ◽  
Wen Ma ◽  
...  
Keyword(s):  
Secondary Metabolites ◽  
Salvia Miltiorrhiza ◽  
Pcr Analysis ◽  
Chinese Medicinal Herb ◽  
Bait Protein ◽  
Reverse Transcription Pcr ◽  
Genome Wide ◽  
Jaz Proteins ◽  
Salvianolic Acids ◽  
Ja Signaling

Salvia miltiorrhiza Bunge (S. miltiorrhiza), a traditional Chinese medicinal herb, contains numerous bioactive components with broad range of pharmacological properties. By increasing the levels of endogenous jasmonate (JA) in plants or treating them with methyl jasmonate (MeJA), the level of tanshinones and salvianolic acids can be greatly enhanced. The jasmonate ZIM (JAZ) proteins belong to the TIFY family, and act as repressors, releasing targeted transcriptional factors in the JA signaling pathway. Herein, we identified and characterized 15 TIFY proteins present in S. miltiorrhiza. Quantitative reverse transcription PCR analysis indicated that the JAZ genes were all constitutively expressed in different tissues and were induced by MeJA treatments. SmJAZ3, which negatively regulates the tanshinones biosynthesis pathway in S. miltiorrhiza and the detailed molecular mechanism is poorly understood. SmJAZ3 acts as a bait protein to capture and identify a WD-repeat containing the protein SmWD40-170. Further molecular and genetic analysis revealed that SmWD40-170 is a positive regulator, promoting the accumulation of secondary metabolites in S. miltiorrhiza. Our study systematically analyzed the TIFY family and speculated a module of the JAZ-WD40 complex provides new insights into the mechanisms regulating the biosynthesis of secondary metabolites in S. miltiorrhiza.

scholarly journals Linear signaling in the Toll-Dorsal pathway of Drosophila: activated Pelle kinase specifies all threshold outputs of gene expression while the bHLH protein Twist specifies a subset

Development ◽  
2002 ◽  
Vol 129 (14) ◽  
pp. 3411-3419 ◽  
Author(s):  
Angelike Stathopoulos ◽  
Michael Levine
Keyword(s):  
Target Genes ◽  
Early Gene ◽  
Bhlh Protein ◽  
Bhlh Transcription Factor ◽  
Gradient System ◽  
Dorsoventral Patterning ◽  
Helix Loop Helix ◽  
Dorsal Pathway ◽  
Toll Signaling ◽  
Toll Receptor

Differential activation of the Toll receptor leads to the formation of a broad Dorsal nuclear gradient that specifies at least three patterning thresholds of gene activity along the dorsoventral axis of precellular embryos. We investigate the activities of the Pelle kinase and Twist basic helix-loop-helix (bHLH) transcription factor in transducing Toll signaling. Pelle functions downstream of Toll to release Dorsal from the Cactus inhibitor. Twist is an immediate-early gene that is activated upon entry of Dorsal into nuclei. Transgenes misexpressing Pelle and Twist were introduced into different mutant backgrounds and the patterning activities were visualized using various target genes that respond to different thresholds of Toll-Dorsal signaling. These studies suggest that an anteroposterior gradient of Pelle kinase activity is sufficient to generate all known Toll-Dorsal patterning thresholds and that Twist can function as a gradient morphogen to establish at least two distinct dorsoventral patterning thresholds. We discuss how the Dorsal gradient system can be modified during metazoan evolution and conclude that Dorsal-Twist interactions are distinct from the interplay between Bicoid and Hunchback, which pattern the anteroposterior axis.

Dual role of the basic helix-loop-helix transcription factor scleraxis in mesoderm formation and chondrogenesis during mouse embryogenesis

Development ◽  
1999 ◽  
Vol 126 (19) ◽  
pp. 4317-4329 ◽  
Author(s):  
D. Brown ◽  
D. Wagner ◽  
X. Li ◽  
J.A. Richardson ◽  
E.N. Olson
Keyword(s):  
Transcription Factor ◽  
Target Genes ◽  
Embryonic Stem ◽  
Primitive Streak ◽  
Axial Skeleton ◽  
Bhlh Transcription Factor ◽  
Basic Helix Loop Helix ◽  
Helix Loop Helix ◽  
Mesoderm Formation ◽  
Cell Layers

Scleraxis is a basic helix-loop-helix (bHLH) transcription factor shown previously to be expressed in developing chondrogenic cell lineages during embryogenesis. To investigate its function in embryonic development, we produced scleraxis-null mice by gene targeting. Homozygous mutant embryos developed normally until the early egg cylinder stage (embryonic day 6.0), when they became growth-arrested and failed to gastrulate. Consistent with this early embryonic phenotype, scleraxis was found to be expressed throughout the embryo at the time of gastrulation before becoming restricted to chondrogenic precursor cells at embryonic day 9.5. At the time of developmental arrest, scleraxis-null embryos consisted of ectodermal and primitive endodermal cell layers, but lacked a primitive streak or recognizable mesoderm. Analysis of molecular markers of the three embryonic germ layers confirmed that scleraxis mutant embryos were unable to form mesoderm. By generating chimeric embryos, using lacZ-marked scleraxis-null and wild-type embryonic stem cells, we examined the ability of mutant cells to contribute to regions of the embryo beyond the time of lethality of homozygous mutants. Scleraxis-null cells were specifically excluded from the sclerotomal compartment of somites, which gives rise to the axial skeleton, and from developing ribs, but were able to contribute to most other regions of the embryo, including mesoderm-derived tissues. These results reveal an essential early role for scleraxis in mesoderm formation, as well as a later role in formation of somite-derived chondrogenic lineages, and suggest that scleraxis target genes mediate these processes.

Ectopic expression of LhMYC2 increases susceptibility to Botrytis cinerea in Arabidopsis thaliana

2020 ◽  
Author(s):  
Qi Cui ◽  
Xue Gao ◽  
Lianjuan Wang ◽  
Guixia Jia
Keyword(s):  
Functional Characterization ◽  
Ectopic Expression ◽  
Defense Responses ◽  
Gray Mold ◽  
Wild Type ◽  
Transcriptional Changes ◽  
Negative Role ◽  
Ja Signaling ◽  
Fungal Inoculation

Gray mold disease, mainly caused by Botrytis elliptica and B. cinerea, leads to severe losses in lily cut flower and bulb production. MYC2 is a critical regulator of the activation of jasmonate (JA)-mediated defense responses in plants. However, information about the lily MYC2 gene is limited. Therefore, functional characterization of MYC2 in lily, especially its role in plant immune responses, should be performed. Here, significant differences between the Botrytis-resistant Lilium hybrid ‘Sorbonne’ and the Botrytis-susceptible ‘Tresor’ were found following B. cinerea inoculation, as indicated by jasmonic acid (JA) and JA-isoleucine (JA-Ile) accumulation and related gene expression. More JA and JA-Ile were detected in ‘Sorbonne’ than in ‘Tresor’ following fungal inoculation, and higher transcript levels of JA biosynthesis genes (LhAOS, LhAOC, and LhOPR3) and a signaling gene (LhCOI1) were detected in ‘Sorbonne’ than in ‘Tresor’. In contrast, expression of the critical signaling regulator LhMYC2 was higher in ‘Tresor’ than in ‘Sorbonne’. LhMYC2 was then isolated from ‘Sorbonne’ and found to be similar to several plant MYC2 homologs that have pivotal roles in JA signaling. The expression of LhMYC2 increased significantly in response to JA and salicylic acid (SA) in ‘Sorbonne’. Ectopic expression of LhMYC2 in Arabidopsis resulted in greater susceptibility to B. cinerea than that observed in wild-type plants. This susceptibility was coupled with the transcriptional changes in SA- and JA-responsive genes. Overall, our findings indicate that LhMYC2 plays a negative role in Arabidopsis resistance to B. cinerea.

scholarly journals Functional characterization of a liverworts bHLH transcription factor involved in the regulation of bisbibenzyls and flavonoids biosynthesis

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Yu Zhao ◽  
Yu-Ying Zhang ◽  
Hui Liu ◽  
Xiao-Shuang Zhang ◽  
Rong Ni ◽  
...  
Keyword(s):  
Vascular Plants ◽  
Functional Characterization ◽  
Bhlh Transcription Factor ◽  
Structural Genes ◽  
Helix Loop Helix ◽  
Family Protein ◽  
Transient Expression Experiment ◽  
Flavonoids Biosynthesis ◽  
Bhlh Transcription Factors

Abstract Background The basic helix-loop-helix (bHLH) transcription factors (TFs), as one of the largest families of TFs, play important roles in the regulation of many secondary metabolites including flavonoids. Their involvement in flavonoids synthesis is well established in vascular plants, but not as yet in the bryophytes. In liverworts, both bisbibenzyls and flavonoids are derived through the phenylpropanoids pathway and share several upstream enzymes. Results In this study, we cloned and characterized the function of PabHLH1, a bHLH family protein encoded by the liverworts species Plagiochasma appendiculatum. PabHLH1 is phylogenetically related to the IIIf subfamily bHLHs involved in flavonoids biosynthesis. A transient expression experiment showed that PabHLH1 is deposited in the nucleus and cytoplasm, while the yeast one hybrid assay showed that it has transactivational activity. When PabHLH1 was overexpressed in P. appendiculatum thallus, a positive correlation was established between the content of bibenzyls and flavonoids and the transcriptional abundance of corresponding genes involved in the biosynthesis pathway of these compounds. The heterologous expression of PabHLH1 in Arabidopsis thaliana resulted in the activation of flavonoids and anthocyanins synthesis, involving the up-regulation of structural genes acting both early and late in the flavonoids synthesis pathway. The transcription level of PabHLH1 in P. appendiculatum thallus responded positively to stress induced by either exposure to UV radiation or treatment with salicylic acid. Conclusion PabHLH1 was involved in the regulation of the biosynthesis of flavonoids as well as bibenzyls in liverworts and stimulated the accumulation of the flavonols and anthocyanins in Arabidopsis.

scholarly journals Cloning, molecular evolution and functional characterization of ZmbHLHl6, the maize ortholog of OsTIP2 (OsbHLH142)

2017 ◽  
Author(s):  
Yongming Liu ◽  
Jia Li ◽  
Gui Wei ◽  
Yonghao Sun ◽  
Yanli Lu ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Expression Patterns ◽  
Functional Characterization ◽  
Protein A ◽  
Reproductive Organs ◽  
Male Reproduction ◽  
Yeast Cells ◽  
Bhlh Transcription Factor ◽  
Helix Loop Helix ◽  
A Genome

AbstractAbstract Basic helix-loop-helix (bHLH) transcription factors play key roles in plant male reproduction. More than 14 bHLH proteins related to pollen development have been cloned from rice and Arabidopsis. However, little is known about the role of the bHLH family in maize microspore development. In this study, the bHLH transcription factor ZmbHLH16 was cloned. ZmbHLH16 shares high similarity with the OsTIP2 (OsbHLH142) protein, a master regulator of the developmental coordination of male reproduction in rice. Expression characterization analysis showed that ZmbHLH16 is preferentially expressed in male reproductive organs and is located in the nucleus. Through nucleotide variation analysis, 36 polymorphic sites in ZmbHLH16, including 23 SNPs and 13 InDels, were detected among 78 maize inbred lines. Neutrality tests and linkage disequilibrium analysis showed that ZmbHLH16 experienced no significant evolutionary pressure. A yeast one-hybrid experiment showed that the first 80 residues in the N-terminus of ZmbHLH16 had transactivation activity, whereas the full length did not. To identify potential ZmbHLH16 interactors, 395 genes that shared similar expression patterns in a genome-wide search were obtained through coexpression analysis. Among these genes, the transcription factor ZmbHLH51 had an expression pattern and subcellular localization similar to those of ZmbHLH16. The interaction between ZmbHLH51 and ZmbHLH16 was verified in yeast cells. In addition to the typical bHLH domain, other regions of ZmbHLH16 were necessary and adequate for its heterodimerization with ZmbHLH51. Our results contribute to a solid foundation for further understanding the functions and mechanisms of ZmbHLH16.

scholarly journals Key Genes in the Jaz Signaling Pathway Are Up-regulated Faster and More Abundantly in Caterpillar-resistant Maize

2021 ◽  
Author(s):  
Yang Han ◽  
DAWN LUTHE
Keyword(s):  
Fall Armyworm ◽  
Defense Responses ◽  
Plant Responses ◽  
Limited Information ◽  
Mechanical Wounding ◽  
Transcript Levels ◽  
Jaz Proteins ◽  
Regulation Function ◽  
Key Genes ◽  
Ja Signaling

Abstract Jasmonic acid (JA) and its derivatives, collectively known as jasmonates (JAs), are important signaling hormones for plant responses against chewing herbivores. In JA signaling networks, jasmonate ZIM-domain (JAZ) proteins are transcriptional repressors that regulate JA-modulated downstream herbivore defenses. JAZ repressors are widely presented in land plants, however, there is only limited information about the regulation/function of JAZ proteins in maize. In this study, we performed a comprehensive expression analysis of ZmJAZ genes with other selected genes in the jasmonate pathway in response to feeding by fall armyworm (Spodoptera frugiperda, FAW), mechanical wounding, and exogenous hormone treatments in two maize genotypes differing in FAW resistance. Results showed that transcript levels of JAZ genes and several key genes in JA-signaling and biosynthesis pathways were rapidly and abundantly expressed in both genotypes in response to these various treatments. However, there were key differences between the two genotypes in the expression of ZmJAZ1 and ZmCOI1a, these two genes were expressed significantly rapidly and abundantly in the resistant line which was tightly regulated by endogenous JA level upon feeding. For instance, transcript levels of ZmJAZ1 increase dramatically within 30 min of FAW-fed Mp708 but not Tx601, correlating with the JA accumulation. The results also demonstrated that wounding or JA treatment alone was not as effective as FAW feeding; this suggests that insect-derived factors are required for optimal defense responses.

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