SRD1 is involved in the auxin-mediated initial thickening growth of storage root by enhancing proliferation of metaxylem and cambium cells in sweetpotato (Ipomoea batatas)

A sweetpotato (Ipomoea batatas cv. ‘Jinhongmi’) MADS-box protein cDNA (SRD1) has been isolated from an early stage storage root cDNA library. The role of the SRD1 gene in the formation of the storage root in sweetpotato was investigated by an expression pattern analysis and characterization of SRD1-overexpressing (ox) transgenic sweetpotato plants. Transcripts of SRD1 were detected only in root tissues, with the fibrous root having low levels of the transcript and the young storage root showing relatively higher transcript levels. SRD1 mRNA was mainly found in the actively dividing cells, including the vascular and cambium cells of the young storage root. The transcript level of SRD1 in the fibrous roots increased in response to 1000 μM indole-3-acetic acid (IAA) applied exogenously. During the early stage of storage root development, the endogenous IAA content and SRD1 transcript level increased concomitantly, suggesting an involvement of SRD1 during the early stage of the auxin-dependent development of the storage root. SRD1-ox sweetpotato plants cultured in vitro produced thicker and shorter fibrous roots than wild-type plants. The metaxylem and cambium cells of the fibrous roots of SRD1-ox plants showed markedly enhanced proliferation, resulting in the fibrous roots of these plants showing an earlier thickening growth than those of wild-type plants. Taken together, these results demonstrate that SRD1 plays a role in the formation of storage roots by activating the proliferation of cambium and metaxylem cells to induce the initial thickening growth of storage roots in an auxin-dependent manner

Callerya atropurpurea suppresses inflammation in vitro and ameliorates gastric injury as well as septic shock in vivo via TLR4/MyD88-dependent cascade

© 2022Background: Callerya atropurpurea is a traditional plant in a tropical zone discovered to have anti-inflammatory functions. Purpose: we want to investigate the mechanism related to anti-inflammation of C. atropurpurea ethanol extract (Ca-EE) both in vitro and in vivo. Study design: Murine macrophage cells and mouse models for gastritis and septic shock were conducted to evaluate the abilities of Ca-EE in anti-inflammation. Methods: Ca-EE was tested by HPLC and LC-MS/MS. NO outcome was checked by Griess reagent test. Cell viabilities were evaluated using MTT assay. Inflammatory cytokines were determined via RT-PCR and ELISA. The mechanism of Ca-EE in anti-inflammation was investigated by luciferase reporter gene assay and immunoblot in transcription level and protein level respectively. Gastric injury and septic shock administrated with Ca-EE were studied by H&E, PCR, and immunoblot. Results: Ca-EE significantly decreased LPS-induced NO production, but hardly stimulated the expression of NO itself. It not only showed no cytotoxicity, but also protected cells from LPS damage. Moreover, Ca-EE decreased TLR4 expression, altered MyD88 recruitment and TRAF6, and suppressed the phospho-Src/PI3K/AKT. Ca-EE inhibited downstream signaling P38, JNK and NF-κB. Finally, Ca-EE alleviated HCl/EtOH-induced gastritis and LPS/poly (I:C)-induced septic shock through the previously mentioned signaling cascades. Conclusion: Ca-EE exhibited an integrated and promising mechanism against TLR4-related inflammation, which shows potential for treating gastritis, septic shock, and other inflammatory diseases.N