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The auxin IAA is a vital plant hormone in controlling growth and development, but our knowledge about its complicated biosynthetic pathways and molecular regulation are still limited and fragmentary. cytokinin induced root waving 2 (ckrw2) was isolated as one of the auxin-deficient mutants in a large-scale forward genetic screen aiming to find more genes functioning in auxin homeostasis and/or its regulation. Here we show that CKRW2 is identical to Histone Monoubiquitination 1 (HUB1), a gene encoding an E3 ligase required for histone H2B monoubiquitination (H2Bub1) in Arabidopsis. In addition to pleiotropic defects in growth and development, loss of CKRW2/HUB1 function also led to typical auxin-deficient phenotypes in roots, which was associated with significantly lower expression levels of several functional auxin synthetic genes, namely TRP2/TSB1, WEI7/ASB1, YUC7 and AMI1. Corresponding defects in H2Bub1 were detected in the coding regions of these genes by chromatin immunoprecipitation (ChIP) analysis, indicating the involvement of H2Bub1 in regulating auxin biosynthesis. Importantly, application of exogenous cytokinin (CK) could stimulate CKRW2/HUB1 expression, providing an epigenetic avenue for CK to regulate the auxin homeostasis. Our results reveal a previously unknown mechanism for regulating auxin biosynthesis via HUB1/2-mediated H2Bub1 at the chromatin level.
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http://dx.doi.org/10.1038/s42003-021-01733-x | DOI Listing |
Physiol Plant
September 2025
Biotechnology Center in Southern Taiwan, Academia Sinica, Tainan, Taiwan.
Epiphytic orchids have evolved specialized adaptive strategies, such as aerial roots with water-absorbing velamen tissues, to cope with water-scarce and nutrient-deficient habitats. Our previous study revealed that the aerial roots of the epiphytic orchid Phalaenopsis aphrodite lack a gravitropic response, raising the possibility that alternative tropic mechanisms may contribute to their adaptation. In this study, we examined the effects of light and moisture on aerial root growth in P.
View Article and Find Full Text PDFPhysiol Plant
September 2025
Plant BioSystems, Department of Agricultural, Food, and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada.
Auxins are involved in the regulation of fruit set and development; however, the role of IAA is unclear in pea (Pisum sativum) since the endogenous auxin 4-Cl-IAA appears to be the auxin stimulating ovary (pericarp) growth. To further understand the role of auxins during fruit development, auxin localization, quantitation, transport, and gene expression activity were assessed in this model legume species. IAA levels and auxin activity (DR5::β-Glucuronidase [GUS] staining and enzyme activity) were substantially reduced in the pericarp vascular tissues, pedicels, and peduncles of fruit upon seed removal, reflecting auxin transport streams derived from the seeds through these tissues.
View Article and Find Full Text PDFArch Microbiol
September 2025
School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, 310053, China.
Endophytic fungi are nonpathogenic fungi that live symbiotically in the interior of healthy plant tissues and form mutualistic associations with their hosts. These fungi are critically involved in promoting plant development, strengthening plant uptake of nutrients, and improving plant resistance to biotic and abiotic stress conditions. Endophytic fungi improve plant growth by synthesizing phytohormones (e.
View Article and Find Full Text PDFmSphere
September 2025
Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Blacksburg, Virginia, USA.
Apicomplexan AP2 (ApiAP2) family proteins are a family of transcription factors that are known to regulate gene expression in apicomplexan pathogens, including . In this study, we focused on TgAP2X-7, a member of the APiAP2 family that is predicted to be essential for fitness. Endogenous tagging of TgAP2X-7 followed by immunofluorescence analysis revealed that it's a cell cycle-regulated nuclear protein with peak expression in the G1 phase.
View Article and Find Full Text PDFFront Plant Sci
August 2025
State Key Laboratory of Tree Genetics and Breeding, Research Institute of Non-Timber Forestry, Chinese Academy of Forestry, Zhengzhou, China.
Introduction: Shikimic acid, as a critical precursor for oseltamivir synthesis in antiviral pharmaceuticals, faces escalating global demand. Although leaves have emerged as a promising natural source of shikimic acid owing to their exceptional content of this valuable compound and substantial biomass production capacity, the molecular mechanisms underlying its biosynthesis and downstream metabolic regulation in leaves remain largely unknown.
Methods: Here, the concentration of shikimic acid in 33 clones were assessed, and 1# (referred as HS) had the highest level.