Asymmetric Total Synthesis of Dragonbloodins A1 and A2

The first asymmetric total synthesis of dragonbloodins A1 and A2, a pair of unprecedented chalcone-flavan heterotrimmers, has been achieved through a series of rationally designed or bioinspired transformations. Key elements of the synthesis include a highly efficient heterotrimerization reaction to assemble the two chalcone units and one flavan unit in one pot and a tandem oxidative dearomatization/cyclization/oxygenation reaction to forge the polycyclic core of dragonbloodins A1 and A2. The present synthesis unambiguously confirms the biogenetic relationship and absolute stereochemistry of dragonbloodins A1 and A2

Analysis of <i>TaPIF</i> promoter <i>cis</i>-elements.

Analysis of TaPIF promoter cis-elements. The 2-kb promoter sequences of TaPIFs were analyzed to identify predicted cis-elements. The identified cis-elements were classified into three categories: hormone-related, development-related, and abiotic stress-related. The color intensity and number in each square indicate the number of each type of cis-element in the promoter region of the indicated gene. The distribution of cis-elements in each category for each gene is shown at right.</p

<i>PIF</i> synteny analysis.

(A) Synteny analysis of PIFs in the wheat genome. Isomorphic TaPIF gene pairs are connected with red lines. (B) Synteny analysis of Di19 genes in wheat, Oryza sativa, Arabidopsis thaliana, and Brachypodium distachyon. The orange bars represent chromosomes in wheat, while the green bars represent chromosomes in rice and B. distachyon. The text on the sides of the bars indicates the chromosome numbers. Gray lines indicate collinearity between the wheat genome and those of other plant species. Red lines show isomorphic PIF gene pairs.</p

The <i>Ka</i>/<i>Ks</i> ratios and duplication times of paralogous <i>TaPIF</i>s in wheat, rice, maize, and <i>Brachypodium distachyon</i>.

The Ka/Ks ratios and duplication times of paralogous TaPIFs in wheat, rice, maize, and Brachypodium distachyon.</p

Phylogenetic relationships, conserved motifs, and gene structures of TaPIFs.

Phylogenetic analysis of PIFs in wheat and four other plant species clustered the proteins into five groups. Left, conserved motifs among the TaPIFs. Right, gene structures of TaPIFs. Untranslated regions are indicated with green boxes, exons are indicated with yellow boxes, and introns are represented by black lines.</p

<i>TaPIF</i> expression levels in fragments per kilobase of transcript per million mapped reads (FPKM).

TaPIF expression levels in fragments per kilobase of transcript per million mapped reads (FPKM).</p

Characterization of PIFs in wheat.

Phytochrome-interacting factors (PIFs) are essential transcription factors for plant growth, development, and stress responses. Although PIF genes have been extensively studied in many plant species, they have not been thoroughly investigated in wheat. Here, we identified 18 PIF genes in cultivated hexaploid wheat (Triticum aestivum L). Phylogenetic analysis, exon-intron structures, and motif compositions revealed the presence of four distinct groups of TaPIFs. Genome-wide collinearity analysis of PIF genes revealed the evolutionary history of PIFs in wheat, Oryza sativa, and Brachypodium distachyon. Cis-regulatory element analysis suggested that TaPIF genes indicated participated in plant development and stress responses. Subcellular localization assays indicated that TaPIF2-1B and TaPIF4-5B were transcriptionally active. Both were found to be localized to the nucleus. Gene expression analyses demonstrated that TaPIFs were primarily expressed in the leaves and were induced by various biotic and abiotic stresses and phytohormone treatments. This study provides new insights into PIF-mediated stress responses and lays a strong foundation for future investigation of PIF genes in wheat.</div

Gene expression patterns of <i>TaPIF</i>s in response to abiotic stress or phytohormone treatment.

(A) Expression profiles of TaPIF genes in wheat exposed to drought (D), heat (H), or combined drought and heat (D&H). (B) Expression profiles of TaPIF genes in wheat exposed to salt or cold stress. CK1 and CK2 were the control samples for the salt and cold stress treatments, respectively. (C) Expression profiles of TaPIF genes in wheat exposed to abscisic acid (ABA), 6-benzylaminopurine (6-BA), salicylic acid (SA), gibberellic acid (GA), or jasmonic acid (JA). CK1 was the control for the ABA, 6-BA, and SA treatments; CK2 was the control for the GA and JA treatments. Analyses were conducted using publicly-available RNA-seq data. All expression values were log2 transformed. The color bars represent the level of gene expression, with blue indicating low expression and red indicating high expression.</p

Conserved motifs in TaPIF proteins.

Phytochrome-interacting factors (PIFs) are essential transcription factors for plant growth, development, and stress responses. Although PIF genes have been extensively studied in many plant species, they have not been thoroughly investigated in wheat. Here, we identified 18 PIF genes in cultivated hexaploid wheat (Triticum aestivum L). Phylogenetic analysis, exon-intron structures, and motif compositions revealed the presence of four distinct groups of TaPIFs. Genome-wide collinearity analysis of PIF genes revealed the evolutionary history of PIFs in wheat, Oryza sativa, and Brachypodium distachyon. Cis-regulatory element analysis suggested that TaPIF genes indicated participated in plant development and stress responses. Subcellular localization assays indicated that TaPIF2-1B and TaPIF4-5B were transcriptionally active. Both were found to be localized to the nucleus. Gene expression analyses demonstrated that TaPIFs were primarily expressed in the leaves and were induced by various biotic and abiotic stresses and phytohormone treatments. This study provides new insights into PIF-mediated stress responses and lays a strong foundation for future investigation of PIF genes in wheat.</div

<i>Cis</i>-regulatory elements in <i>TaPIF</i> promoters.

Phytochrome-interacting factors (PIFs) are essential transcription factors for plant growth, development, and stress responses. Although PIF genes have been extensively studied in many plant species, they have not been thoroughly investigated in wheat. Here, we identified 18 PIF genes in cultivated hexaploid wheat (Triticum aestivum L). Phylogenetic analysis, exon-intron structures, and motif compositions revealed the presence of four distinct groups of TaPIFs. Genome-wide collinearity analysis of PIF genes revealed the evolutionary history of PIFs in wheat, Oryza sativa, and Brachypodium distachyon. Cis-regulatory element analysis suggested that TaPIF genes indicated participated in plant development and stress responses. Subcellular localization assays indicated that TaPIF2-1B and TaPIF4-5B were transcriptionally active. Both were found to be localized to the nucleus. Gene expression analyses demonstrated that TaPIFs were primarily expressed in the leaves and were induced by various biotic and abiotic stresses and phytohormone treatments. This study provides new insights into PIF-mediated stress responses and lays a strong foundation for future investigation of PIF genes in wheat.</div