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In grass cell walls, ferulic acid (FA) serves as an important cross-linker between cell wall polymers, such as arabinoxylan (AX) and lignin, affecting the physicochemical properties of the cell walls as well as the utilization properties of grass lignocellulose for biorefinering. Here, we demonstrate that hydroxycinnamaldehyde dehydrogenase (HCALDH) plays a crucial role in the biosynthesis of the FA used for cell wall feruloylation in rice (Oryza sativa). Bioinformatic and gene expression analyses of aldehyde dehydrogenases (ALDHs) identified two rice ALDH subfamily 2C members, OsHCALDH2 (OsALDH2C2) and OsHCALDH3 (OsALDH2C3), potentially involved in cell wall feruloylation in major vegetative tissues of rice. CRISPR-Cas9 genome editing of OsHCALDH2 and OsHCALDH3 revealed that the contents of AX-bound ferulate were reduced by up to ~45% in the cell walls of the HCALDH-edited mutants, demonstrating their roles in cell wall feruloylation. The abundance of hemicellulosic sugars including arabinosyl units on AX was notably reduced in the cell walls of the HCALDH-edited mutants, whereas cellulose and lignin contents remained unaffected. In addition to reducing cell wall-bound ferulate, the loss of OsHCALDH2 and/or OsHCALDH3 also partially reduced cell wall-bound p-coumarate and sinapate in the vegetative tissues of rice, whereas it did not cause detectable changes in the amount of γ-oryzanol (feruloyl sterols) in rice seeds. Furthermore, the HCALDH-edited mutants exhibited improved cell wall saccharification efficiency, both with and without alkaline pretreatment, plausibly due to the reduction in cell wall cross-linking FA. Overall, HCALDH appears to present a potent bioengineering target for enhancing utilization properties of grass lignocellulose., (© 2024 Society for Experimental Biology and John Wiley & Sons Ltd.)

Purpose: To clarify the clinical and pathologic findings of 7 patients with inflamed juvenile conjunctival nevus (IJCN) treated with tacrolimus., Study Design: Retrospective study., Subjects and Methods: The medical records of 7 male patients diagnosed with IJCN between February 2007 and October 2022 at the Kansai Medical University Hospital and Ideta Eye Hospital were retrospectively reviewed. The patients' mean age was 11.3 (8-20) years, and the average follow-up period was 18 months. The patients underwent anterior segment optical coherence tomography (AS-OCT) and anterior segment optical coherence tomography angiography (AS-OCTA). All the patients were treated with steroids or immunosuppressant eye drops, or both. Histopathologic examinations were performed on specimens resected from 2 patients., Results: The clinical characteristics of IJCN were as follows: (1) presence of cysts within a pigmented conjunctival mass, (2) tumor accompanied by feeder vessels, and (3) predominantly found in boys with allergic diseases. AS-OCT and AS-OCTA revealed the presence of a cystic structure with poor vascular signals within it and numerous vessels distributed on the sclera underlying the lesion. Immunosuppressant eye drops relieved the congestion, diminished the inflow vessels, and induced shrinkage of the cysts in all the patients. Histopathologic examinations revealed infiltration of inflammatory cells such as lymphocytes and macrophages and low proliferative activity of melanocytes with no division pattern., Conclusions: This study clarified the clinical and histologic characteristics of IJCN. Noninvasive AS-OCT and AS-OCTA might be useful for diagnosing IJCN. The histopathologic findings of this study indicate that immunosuppressive and antiallergic agents can effectively bring about disease remission., Competing Interests: Declarations Conflict of interest A. Tomoda, None; K. Araki-Sasaki, None; H. Obata, None; S. Ideta, None; M. Kuroda, None; K. Fujita, None; Y. Osakabe, None; K. Takahashi, None., (© 2024. The Author(s).)

Genome-editing tools such as the clustered regularly interspaced short palindromic repeats/Cas9 (CRISPR/Cas9) system have become essential tools for increasing the efficiency and accuracy of plant breeding. Using such genome-editing tools on maize, one of the most important cereal crops of the world, will greatly benefit the agriculture and the mankind. Conventional genome-editing methods typically used for maize involve insertion of a Cas9-guide RNA expression cassette and a selectable marker in the genome DNA; however, using such methods, it is essential to eliminate the inserted DNA cassettes to avoid legislative concerns on gene-modified organisms. Another major hurdle for establishing an efficient and broadly applicable DNA-free genome-editing system for maize is presented by recalcitrant genotypes/cultivars, since cell/tissue culture and its subsequent regeneration into plantlets are crucial for producing transgenic and/or genome-edited maize. In this study, to establish a DNA-free genome-editing system for recalcitrant maize genotypes/cultivars, Cas9-gRNA ribonucleoproteins were directly delivered into zygotes isolated from the pollinated flowers of the maize-B73 cultivar. The zygotes successfully developed and were regenerated into genome-edited plantlets by co-culture with phytosulfokine, a peptide phytohormone. The method developed herein made it possible to obtain DNA- and selectable-marker-free genome-edited recalcitrant maize genotypes/cultivars with high efficiency. This method can advance the molecular breeding of maize and other important cereals, regardless of their recalcitrant characteristics., (© The Author(s) 2024. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site–for further information please contact journals.permissions@oup.com.)

Sulfur (S) is an essential macronutrient for plant growth and metabolism. SULTR2;1 is a low-affinity sulfate transporter facilitating the long-distance transport of sulfate in Arabidopsis. The physiological function of SULTR2;1 in the plant life cycle still needs to be determined. Therefore, we analyzed the sulfate transport, S-containing metabolite accumulation and plant growth using Arabidopsis SULTR2;1 disruption lines, sultr2;1-1 and sultr2;1-2, from seedling to mature growth stages to clarify the metabolic and physiological roles of SULTR2;1. We observed that sulfate distribution to the stems was affected in sultr2;1 mutants, resulting in decreased levels of sulfate, cysteine, glutathione (GSH) and total S in the stems, flowers and siliques; however, the GSH levels increased in the rosette leaves. This suggested the essential role of SULTR2;1 in sulfate transport from rosette leaves to the primary stem. In addition, sultr2;1 mutants unexpectedly bolted earlier than the wild-type without affecting the plant biomass. Correlation between GSH levels in rosette leaves and the bolting timing suggested that the rosette leaf GSH levels or limited sulfate transport to the early stem can trigger bolting. Overall, this study demonstrated the critical roles of SULTR2;1 in maintaining the S metabolite levels in the aerial part and transitioning from the vegetative to the reproductive growth phase., (© The Author(s) 2024. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site–for further information please contact journals.permissions@oup.com.)

Background: Amphiregulin (AREG) is a ligand of epidermal growth factor receptor (EGFR), which plays an important role in injury-induced kidney fibrosis. However, the clinical significance of serum soluble AREG in chronic kidney disease (CKD) is unclear. In this study, we elucidated the clinical significance of serum soluble AREG in CKD by analyzing the association of serum soluble AREG levels with renal function and other clinical parameters in patients with CKD., Methods: In total, 418 Japanese patients with CKD were enrolled, and serum samples were collected for the determination of soluble AREG and creatinine (Cr) levels, and other clinical parameters. Additionally, these parameters were evaluated after 2 and 3 years. Moreover, immunohistochemical assay was performed ate AREG expression in the kidney tissues of patients with CKD., Results: Soluble AREG levels were positively correlated with serum Cr (p < 0.0001). Notably, initial AREG levels were positively correlated with changes in renal function (ΔCr) after 2 (p < 0.0001) and 3 years (P = 0.048). Additionally, soluble AREG levels were significantly higher (p < 0.05) in patients with diabetic nephropathy or primary hypertension. Moreover, AREG was highly expressed in renal tubular cells in patients with advanced CKD, but only weakly expressed in patients with preserved renal function., Conclusion: Serum soluble AREG levels were significantly correlated with renal function, and changes in renal function after 2 and 3 years, indicating that serum soluble AREG levels might serve as a biomarker of renal function and renal prognosis in CKD., (© 2024. The Author(s), under exclusive licence to Japanese Society of Nephrology.)

Grasses are abundant feedstocks that can supply lignocellulosic biomass for production of cell-wall-derived chemicals. In grass cell walls, lignin is acylated with p-coumarate. These p-coumarate decorations arise from the incorporation of monolignol p-coumarate conjugates during lignification. A previous biochemical study identified a rice (Oryza sativa) BAHD acyltransferase (AT) with p-coumaroyl-CoA:monolignol transferase (PMT) activity in vitro. In this study, we determined that that enzyme, which we name OsPMT1 (also known as OsAT4), and the closely related OsPMT2 (OsAT3) harbor similar catalytic activity toward monolignols. We generated rice mutants deficient in either or both OsPMT1 and OsPMT2 by CRISPR/Cas9-mediated mutagenesis and subjected the mutants' cell walls to analysis using chemical and nuclear magnetic resonance methods. Our results demonstrated that OsPMT1 and OsPMT2 both function in lignin p-coumaroylation in the major vegetative tissues of rice. Notably, lignin-bound p-coumarate units were undetectable in the ospmt1 ospmt2-2 double-knockout mutant. Further, in-depth structural analysis of purified lignins from the ospmt1 ospmt2-2 mutant compared with control lignins from wild-type rice revealed stark changes in polymer structures, including alterations in syringyl/guaiacyl aromatic unit ratios and inter-monomeric linkage patterns, and increased molecular weights. Our results provide insights into lignin polymerization in grasses that will be useful for the optimization of bioengineering approaches for the effective use of biomass in biorefineries., Competing Interests: Conflict of interest statement. None declared., (© American Society of Plant Biologists 2023. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)