Search

In recent years, there has been increasing interest in exploring the potential therapeutic advantages of Citrullus mucosospermus extracts (CME) for nonalcoholic steatohepatitis (NASH). In this study, we investigated the therapeutic effects of CME on NASH using a mice model. High-performance liquid chromatography (HPLC) was employed to identify cucurbitacin E and cucurbitacin E-2-O-glucoside from the CME. Although CME did not significantly alter the serum lipid levels in methionine- and choline-deficient (MCD) mice, it demonstrated a protective effect against MCD diet-induced liver damage. CME reduced histological markers, reduced alanine transaminase (ALT) and aspartame transaminase (AST) levels, and modulated key NASH-related genes, including C/EBPα, PPARγ, Fas, and aP2. In addition, CME was found to restore hormone-sensitive lipase (HSL) and adipose triglyceride lipase (ATGL) activity, both crucial for fat catabolism, and reduced the levels of pro-inflammatory cytokines. Furthermore, CME demonstrated the potential to mitigate oxidative stress by maintaining or enhancing the activation and expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and superoxide dismutase (SOD), both pivotal players in antioxidant defense mechanisms. These findings underscore the promising therapeutic potential of CME in ameliorating liver damage, inflammation, and oxidative stress associated with NASH. [ABSTRACT FROM AUTHOR]

Heterotrimeric G proteins are important transducers of receptor signaling, functioning in plants with CLAVATA receptors in controlling shoot meristem size and with pathogen-associated molecular pattern receptors in basal immunity. However, whether specific members of the heterotrimeric complex potentiate cross-talk between development and defense, and the extent to which these functions are conserved across species, have not yet been addressed. Here we used CRISPR/Cas9 to knock out the maize G protein β subunit gene (Gβ) and found that the mutants are lethal, differing from those in Arabidopsis, in which homologous mutants have normal growth and fertility. We show that lethality is caused not by a specific developmental arrest, but by autoimmunity. We used a genetic diversity screen to suppress the lethal Gβ phenotype and also identified a maize Gβ allele with weak autoimmune responses but strong development phenotypes. Using these tools, we show that Gβ controls meristem size in maize, acting epistatically with G protein α subunit gene (Gα), suggesting that Gβ and Gα function in a common signaling complex. Furthermore, we used an association study to show that natural variation in Gβ influences maize kernel row number, an important agronomic trait. Our results demonstrate the dual role of Gβ in immunity and development in a cereal crop and suggest that it functions in cross-talk between these competing signaling networks. Therefore, modification of Gβ has the potential to optimize the trade-off between growth and defense signaling to improve agronomic production. [ABSTRACT FROM AUTHOR]

The promotive effects of brassinosteroids (BRs) on plant growth and development have been widely investigated; however, it is not known whether BRs directly affect nutrient uptake. Here, we explored the possibility of a direct relationship between BRs and ammonium uptake via AMT1-type genes in rice (Oryza sativa). BR treatment increased the expression of AMT1;1 and AMT1;2, whereas in the mutant d61-1, which is defective in the BR-receptor gene BRI1, BR-dependent expression of these genes was suppressed. We then employed Related to ABI3/VP1-Like 1 (RAVL1), which is involved in BR homeostasis, to investigate BR-mediated AMT1 expression and its effect on NH4+ uptake in rice roots. AMT1;2 expression was lower in the ravl1 mutant, but higher in the RAVL1-overexpressing lines. EMSA and ChIP analyses showed that RAVL1 activates the expression of AMT1;2 by directly binding to E-box motifs in its promoter. Moreover, 15NH4+ uptake, cellular ammonium contents, and root responses to methyl-ammonium strongly depended on RAVL1 levels. Analysing AMT1;2 expression levels in different crosses between BRI1 and RAVL1 mutant and overexpression lines indicated that RAVL1 acts downstream of BRI1 in the regulation of AMT1;2. Thus, the present study shows how BRs may be involved in the transcriptional regulation of nutrient transporters to modulate their uptake capacity. [ABSTRACT FROM AUTHOR]

Shoot meristems are maintained by pluripotent stem cells that are controlled by CLAVATA-WUSCHEL feedback signaling. This pathway, which coordinates stem cell proliferation with differentiation, was first identified in Arabidopsis, but appears to be conserved in diverse higher plant species. In this Review, we highlight the commonalities and differences between CLAVATA-WUSCHEL pathways in different species, with an emphasis on Arabidopsis, maize, rice and tomato. We focus on stem cell control in shoot meristems, but also briefly discuss the role of these signaling components in root meristems. [ABSTRACT FROM AUTHOR]

Lamina inclination is a key agronomical character that determines plant architecture and is sensitive to auxin and brassinosteroids (BRs). Loose Plant Architecture1 (LPA1) in rice (Oryza sativa) and its Arabidopsis homologues (SGR5/AtIDD15) have been reported to control plant architecture and auxin homeostasis. This study explores the role of LPA1 in determining lamina inclination in rice. LPA1 acts as a positive regulator to suppress lamina bending. Genetic and biochemical data indicate that LPA1 suppresses the auxin signalling that interacts with C-22-hydroxylated and 6-deoxo BRs, which regulates lamina inclination independently of OsBRI1. Mutant lpa1 plants are hypersensitive to indole-3-acetic acid (IAA) during the lamina inclination response, which is suppressed by the brassinazole (Brz) inhibitor of C-22 hydroxylase involved in BR synthesis. A strong synergic effect is detected between lpa1 and d2 (the defective mutant for catalysis of C-23-hydroxylated BRs) during IAA-mediated lamina inclination. No significant interaction between LPA1 and OsBRI1 was identified. The lpa1 mutant is sensitive to C-22-hydroxylated and 6-deoxo BRs in the d61-1 (rice BRI1 mutant) background. We present evidence verifying that two independent pathways function via either BRs or BRI1 to determine IAA-mediated lamina inclination in rice. RNA sequencing analysis and qRT-PCR indicate that LPA1 influences the expression of three OsPIN genes (OsPIN1a, OsPIN1c and OsPIN3a), which suggests that auxin flux might be an important factor in LPA1-mediated lamina inclination in rice. [ABSTRACT FROM AUTHOR]

Indeterminate 1 ( Id1), a classical flowering gene first reported in 1946, is one of the earliest genes whose expression in leaf tissues affects the floral transition in the shoot meristem. How Id1 is integrated into the flowering process is largely unknown. In this study, we examined the genetic action of the rice ( Oryza sativa) ortholog OsId1. In rice, OsId1 is preferentially expressed in young leaves, but the overall expression pattern is broader than that in maize ( Zea mays). OsId1 is able to activate transcription in yeast. RNAi mutants show a delay in flowering under both short-day (SD) and long-day (LD) conditions. OsId1 regulates the expression of Ehd1 ( Early heading date 1) and its downstream genes, including Hd3a (a rice ortholog of FT) and RFT1 ( Rice Flowering Locus T1), under both SD and LD conditions. In rice, the expression of Ehd1 is also controlled by the photoperiodic flowering genes OsGI (a rice ortholog of GI) and OsMADS51. However, the expression of OsId1 is independent of OsGI, OsMADS51, and OsMADS50 (a rice SOC1 ortholog). This study demonstrates that the activation of Ehd1 by OsId1 is required for the promotion of flowering. [ABSTRACT FROM AUTHOR]

OSH6 ( Oryza sativa Homeobox6) is an ortholog of lg3 (Liguleless3) in maize. We generated a novel allele, termed OSH6-Ds, by inserting a defective Ds element into the third exon of OSH6, which resulted in a truncated OSH6 mRNA. The truncated mRNA was expressed ectopically in leaf tissues and encoded the N-terminal region of OSH6, which includes the KNOX1 and partial KNOX2 subdomains. This recessive mutant showed outgrowth of bracts or produced leaves at the basal node of the panicle. These phenotypes distinguished it from the OSH6 transgene whose ectopic expression led to a “blade to sheath transformation” phenotype at the midrib region of leaves, similar to that seen in dominant Lg3 mutants. Expression of a similar truncated OSH6 cDNA from the 35S promoter ( 35S:: ΔOSH6) confirmed that the ectopic expression of this product was responsible for the aberrant bract development. These data suggest that OSH6-Ds interferes with a developmental mechanism involved in bract differentiation, especially at the basal nodes of panicles. [ABSTRACT FROM AUTHOR]