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Febres VJ, Fadli A, Meyering B, Yu F, Bowman KD, Chaparro JX, Albrecht U. Dissection of transcriptional events in graft incompatible reactions of "Bearss" lemon ( Citrus limon) and "Valencia" sweet orange ( C. sinensis) on a novel citrandarin ( C. reticulata × Poncirus trifoliata) rootstock. FRONTIERS IN PLANT SCIENCE 2024; 15:1421734. [PMID: 38966146 PMCID: PMC11222572 DOI: 10.3389/fpls.2024.1421734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/22/2024] [Accepted: 06/03/2024] [Indexed: 07/06/2024]
Abstract
Citrus is commercially propagated via grafting, which ensures trees have consistent fruit traits combined with favorable traits from the rootstock such as soil adaptability, vigor, and resistance to soil pathogens. Graft incompatibility can occur when the scion and rootstock are not able to form a permanent, healthy union. Understanding and preventing graft incompatibility is of great importance in the breeding of new fruit cultivars and in the choice of scion and rootstock by growers. The rootstock US-1283, a citrandarin generated from a cross of "Ninkat" mandarin (Citrus reticulata) and "Gotha Road" #6 trifoliate orange (Poncirus trifoliata), was released after years of field evaluation because of its superior productivity and good fruit quality on "Hamlin" sweet orange (C. sinensis) under Florida's growing conditions. Subsequently, it was observed that trees of "Bearss" lemon (C. limon) and "Valencia" sweet orange (C. sinensis) grafted onto US-1283 exhibited unhealthy growth near the graft union. The incompatibility manifested as stem grooving and necrosis underneath the bark on the rootstock side of the graft. Another citrandarin rootstock, US-812 (C. reticulata "Sunki" × P. trifoliata "Benecke"), is fully graft compatible with the same scions. Transcriptome analysis was performed on the vascular tissues above and below the graft union of US-812 and US-1283 graft combinations with "Bearss" and "Valencia" to identify expression networks associated with incompatibility and help understand the processes and potential causes of incompatibility. Transcriptional reprogramming was stronger in the incompatible rootstock than in the grafted scions. Differentially expressed genes (DEGs) in US-1283, but not the scions, were associated with oxidative stress and plant defense, among others, similar to a pathogen-induced immune response localized to the rootstock; however, no pathogen infection was detected. Therefore, it is hypothesized that this response could have been triggered by signaling miscommunications between rootstock and scion either through (1) unknown molecules from the scion that were perceived as danger signals by the rootstock, (2) missing signals from the scion or missing receptors in the rootstock necessary for the formation of a healthy graft union, (3) the overall perception of the scion by the rootstock as non-self, or (4) a combination of the above.
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Affiliation(s)
- Vicente J. Febres
- Horticultural Sciences Department, University of Florida/Institute of Food and Agricultural Sciences (IFAS), Gainesville, FL, United States
| | - Anas Fadli
- Southwest Florida Research and Education Center, University of Florida/Institute of Food and Agricultural Sciences (IFAS), Immokalee, FL, United States
| | - Bo Meyering
- Southwest Florida Research and Education Center, University of Florida/Institute of Food and Agricultural Sciences (IFAS), Immokalee, FL, United States
| | - Fahong Yu
- Interdisciplinary Center for Biotechnology Research (ICBR), University of Florida, Gainesville, FL, United States
| | - Kim D. Bowman
- Horticultural Research Laboratory, United States Department of Agriculture (USDA), Fort Pierce, FL, United States
| | - Jose Xavier Chaparro
- Horticultural Sciences Department, University of Florida/Institute of Food and Agricultural Sciences (IFAS), Gainesville, FL, United States
| | - Ute Albrecht
- Southwest Florida Research and Education Center, University of Florida/Institute of Food and Agricultural Sciences (IFAS), Immokalee, FL, United States
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Sulaiman AA, Al-Ansari DE, Ali R, Aouida M, Ramotar D. Mft1, identified from a genome-wide screen of the yeast haploid mutants, mediates cell cycle arrest to counteract quinoxaline-induced toxicity. Front Genet 2024; 14:1296383. [PMID: 38283148 PMCID: PMC10811161 DOI: 10.3389/fgene.2023.1296383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Accepted: 12/31/2023] [Indexed: 01/30/2024] Open
Abstract
Quinoxaline is a heterocyclic compound with a two-membered ring structure that undergoes redox cycling to produce toxic free radicals. It has antiviral, antibacterial, antifungal, and antitumor activities. However, the biological functions that are involved in mounting a response against the toxic effects of quinoxaline have not been investigated. Herein, we performed a genome-wide screen using the yeast haploid mutant collection and reported the identification of 12 mutants that displayed varying sensitivity towards quinoxaline. No mutant was recovered that showed resistance to quinoxaline. The quinoxaline-sensitive mutants were deleted for genes that encode cell cycle function, as well as genes that belong to other physiological pathways such as the vacuolar detoxification process. Three of the highly sensitive gene-deletion mutants lack the DDC1, DUN1, and MFT1 genes. While Ddc1 and Dun1 are known to perform roles in the cell cycle arrest pathway, the role of Mft1 remains unclear. We show that the mft1Δ mutant is as sensitive to quinoxaline as the ddc1Δ mutant. However, the double mutant ddc1Δ mft1Δ lacking the DDC1 and MFT1 genes, is extremely sensitive to quinoxaline, as compared to the ddc1Δ and mft1Δ single mutants. We further show that the mft1Δ mutant is unable to arrest in the G2/M phase in response to the drug. We conclude that Mft1 performs a unique function independent of Ddc1 in the cell cycle arrest pathway in response to quinoxaline exposure. This is the first demonstration that quinoxaline exerts its toxic effect likely by inducing oxidative DNA damage causing cell cycle arrest. We suggest that clinical applications of quinoxaline and its derivatives should entail targeting cancer cells with defective cell cycle arrest.
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Affiliation(s)
- Abdallah Alhaj Sulaiman
- Qatar Foundation, Division of Biological and Biomedical Sciences, College of Health and Life Sciences, Hamad Bin Khalifa University, Doha, Qatar
| | - Dana E. Al-Ansari
- Qatar Foundation, Division of Biological and Biomedical Sciences, College of Health and Life Sciences, Hamad Bin Khalifa University, Doha, Qatar
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Reem Ali
- Qatar Foundation, Division of Biological and Biomedical Sciences, College of Health and Life Sciences, Hamad Bin Khalifa University, Doha, Qatar
| | - Mustapha Aouida
- Qatar Foundation, Division of Biological and Biomedical Sciences, College of Health and Life Sciences, Hamad Bin Khalifa University, Doha, Qatar
| | - Dindial Ramotar
- Qatar Foundation, Division of Biological and Biomedical Sciences, College of Health and Life Sciences, Hamad Bin Khalifa University, Doha, Qatar
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Zheng F, Georgescu RE, Yao NY, O'Donnell ME, Li H. DNA is loaded through the 9-1-1 DNA checkpoint clamp in the opposite direction of the PCNA clamp. Nat Struct Mol Biol 2022; 29:376-385. [PMID: 35314830 PMCID: PMC9010301 DOI: 10.1038/s41594-022-00742-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Accepted: 02/11/2022] [Indexed: 12/11/2022]
Abstract
The 9-1-1 DNA checkpoint clamp is loaded onto 5'-recessed DNA to activate the DNA damage checkpoint that arrests the cell cycle. The 9-1-1 clamp is a heterotrimeric ring that is loaded in Saccharomyces cerevisiae by Rad24-RFC (hRAD17-RFC), an alternate clamp loader in which Rad24 replaces Rfc1 in the RFC1-5 clamp loader of proliferating cell nuclear antigen (PCNA). The 9-1-1 clamp loading mechanism has been a mystery, because, unlike RFC, which loads PCNA onto a 3'-recessed junction, Rad24-RFC loads the 9-1-1 ring onto a 5'-recessed DNA junction. Here we report two cryo-EM structures of Rad24-RFC-DNA with a closed or 27-Å open 9-1-1 clamp. The structures reveal a completely unexpected mechanism by which a clamp can be loaded onto DNA. Unlike RFC, which encircles DNA, Rad24 binds 5'-DNA on its surface, not inside the loader, and threads the 3' ssDNA overhang into the 9-1-1 clamp from above the ring.
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Affiliation(s)
- Fengwei Zheng
- Department of Structural Biology, Van Andel Institute, Grand Rapids, MI, USA
| | - Roxana E Georgescu
- DNA Replication Laboratory, The Rockefeller University, New York, NY, USA
| | - Nina Y Yao
- DNA Replication Laboratory, The Rockefeller University, New York, NY, USA
| | - Michael E O'Donnell
- DNA Replication Laboratory, The Rockefeller University, New York, NY, USA.
- Howard Hughes Medical Institute, The Rockefeller University, New York, NY, USA.
| | - Huilin Li
- Department of Structural Biology, Van Andel Institute, Grand Rapids, MI, USA.
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Zhang T, Jing JL, Liu L, He Y. ZmRAD17 Is Required for Accurate Double-Strand Break Repair During Maize Male Meiosis. FRONTIERS IN PLANT SCIENCE 2021; 12:626528. [PMID: 33719299 PMCID: PMC7952653 DOI: 10.3389/fpls.2021.626528] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Accepted: 02/09/2021] [Indexed: 06/12/2023]
Abstract
RAD17, a replication factor C (RFC)-like DNA damage sensor protein, is involved in DNA checkpoint control and required for both meiosis and mitosis in yeast and mammals. In plant, the meiotic function of RAD17 was only reported in rice so far. Here, we identified and characterized the RAD17 homolog in maize. The Zmrad17 mutants exhibited normal vegetative growth but male was partially sterile. In Zmrad17 pollen mother cells, non-homologous chromosome entanglement and chromosome fragmentation were frequently observed. Immunofluorescence analysis manifested that DSB formation occurred as normal and the loading pattern of RAD51 signals was similar to wild-type at the early stage of prophase I in the mutants. The localization of the axial element ASY1 was normal, while the assembly of the central element ZYP1 was severely disrupted in Zmrad17 meiocytes. Surprisingly, no obvious defect in female sterility was observed in Zmrad17 mutants. Taken together, our results suggest that ZmRAD17 is involved in DSB repair likely by promoting synaptonemal complex assembly in maize male meiosis. These phenomena highlight a high extent of divergence from its counterpart in rice, indicating that the RAD17 dysfunction can result in a drastic dissimilarity in meiotic outcome in different plant species.
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Affiliation(s)
- Ting Zhang
- Ministry of Education Key Laboratory of Crop Heterosis and Utilization, National Maize Improvement Center of China, College of Agronomy and Biotechnology, China Agricultural University, Beijing, China
| | - Ju-Li Jing
- Ministry of Education Key Laboratory of Crop Heterosis and Utilization, National Maize Improvement Center of China, College of Agronomy and Biotechnology, China Agricultural University, Beijing, China
| | - Lei Liu
- Beijing Key Lab of Plant Resource Research and Development, Beijing Technology and Business University, Beijing, China
| | - Yan He
- Ministry of Education Key Laboratory of Crop Heterosis and Utilization, National Maize Improvement Center of China, College of Agronomy and Biotechnology, China Agricultural University, Beijing, China
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Li L, Zhang Z. Recombinant expression and characterization of yeast Mrc1, a DNA replication checkpoint mediator. Prep Biochem Biotechnol 2019; 50:198-203. [PMID: 31755848 DOI: 10.1080/10826068.2019.1692216] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
In Saccharomyces cerevisiae, Mrc1 (homolog of human Claspin and mediator of replication checkpoint) is not only a part of the replication machine, but also participates in the replication stress response when DNA replication is blocked by hydroxyurea. Since Mrc1 is expressed in a small amount in cells and has many proteins interacting with it as a mediator, it is difficult to obtain Mrc1 with high concentration and purity. This article reports the purification of a stable truncation of Mrc1 and the full length Mrc1. High concentration and high purity of Mrc1 was obtained and the three-dimensional structure of Mrc1 was analyzed, which is a ring with a hole in the center. At the same time, we found that Mrc1 has an interaction with Rad24-RFC a clamp loader in the replication checkpoint, and can form a complex with it, implying that we can assemble large replication checkpoint complexes in vitro. These results initially reveal the ring structure of Mrc1 and its interaction with Rad24-RFC in replication checkpoints in S. cerevisiae.
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Affiliation(s)
- Lanjing Li
- First Affiliated Hospital of USTC, School of Life Sciences, University of Science and Technology of China, Hefei, China
| | - Zhihui Zhang
- First Affiliated Hospital of USTC, School of Life Sciences, University of Science and Technology of China, Hefei, China
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