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Tang Q, Xu D, Lenzen B, Brachmann A, Yapa MM, Doroodian P, Schmitz-Linneweber C, Masuda T, Hua Z, Leister D, Kleine T. GENOMES UNCOUPLED PROTEIN1 binds to plastid RNAs and promotes their maturation. PLANT COMMUNICATIONS 2024:101069. [PMID: 39169625 DOI: 10.1016/j.xplc.2024.101069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Revised: 08/05/2024] [Accepted: 08/20/2024] [Indexed: 08/23/2024]
Abstract
Plastid biogenesis and the coordination of plastid and nuclear genome expression through anterograde and retrograde signaling are essential for plant development. GENOMES UNCOUPLED1 (GUN1) plays a central role in retrograde signaling during early plant development. The putative function of GUN1 has been extensively studied, but its molecular function remains controversial. Here, we evaluate published transcriptome data and generate our own data from gun1 mutants grown under signaling-relevant conditions to show that editing and splicing are not relevant for GUN1-dependent retrograde signaling. Our study of the plastid (post)transcriptome of gun1 seedlings with white and pale cotyledons demonstrates that GUN1 deficiency significantly alters the entire plastid transcriptome. By combining this result with a pentatricopeptide repeat code-based prediction and experimental validation by RNA immunoprecipitation experiments, we identified several putative targets of GUN1, including tRNAs and RNAs derived from ycf1.2, rpoC1, and rpoC2 and the ndhH-ndhA-ndhI-ndhG-ndhE-psaC-ndhD gene cluster. The absence of plastid rRNAs and the significant reduction of almost all plastid transcripts in white gun1 mutants account for the cotyledon phenotype. Our study provides evidence for RNA binding and maturation as the long-sought molecular function of GUN1 and resolves long-standing controversies. We anticipate that our findings will serve as a basis for subsequent studies on mechanisms of plastid gene expression and will help to elucidate the function of GUN1 in retrograde signaling.
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Affiliation(s)
- Qian Tang
- Plant Molecular Biology (Botany), Faculty of Biology, Ludwig-Maximilians-University München, 82152 Martinsried, Germany
| | - Duorong Xu
- Plant Molecular Biology (Botany), Faculty of Biology, Ludwig-Maximilians-University München, 82152 Martinsried, Germany
| | - Benjamin Lenzen
- Molecular Genetics, Humboldt-University Berlin, Philippstr. 13, 10115 Berlin, Germany
| | - Andreas Brachmann
- Biocenter of the LMU Munich, Genetics Section, Grosshaderner Str. 2-4, 82152 Planegg-Martinsried, Germany
| | - Madhura M Yapa
- Department of Environmental and Plant Biology, Ohio University, Athens, OH 45701, USA
| | - Paymon Doroodian
- Department of Environmental and Plant Biology, Ohio University, Athens, OH 45701, USA
| | | | - Tatsuru Masuda
- Graduate School of Arts and Sciences, The University of Tokyo, Komaba, Meguro-ku 153-8902, Tokyo, Japan
| | - Zhihua Hua
- Department of Environmental and Plant Biology, Ohio University, Athens, OH 45701, USA
| | - Dario Leister
- Plant Molecular Biology (Botany), Faculty of Biology, Ludwig-Maximilians-University München, 82152 Martinsried, Germany
| | - Tatjana Kleine
- Plant Molecular Biology (Botany), Faculty of Biology, Ludwig-Maximilians-University München, 82152 Martinsried, Germany.
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Xu D, Leister D, Kleine T. Identification of a highly drought-resistant pp7l hda6 mutant. FRONTIERS IN PLANT SCIENCE 2024; 15:1341576. [PMID: 38887464 PMCID: PMC11180769 DOI: 10.3389/fpls.2024.1341576] [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: 11/20/2023] [Accepted: 05/09/2024] [Indexed: 06/20/2024]
Abstract
Plants have developed efficient strategies to counteract drought stress, including stomata closure, significant changes in nuclear gene expression, and epigenetic mechanisms. Previously, we identified Arabidopsis thaliana PROTEIN PHOSPHATASE7-LIKE (PP7L) as an extrachloroplastic protein that promotes chloroplast development. In addition, it was shown that PP7L is involved in high light and salt tolerance. Here, we demonstrate that the pp7l mutant can withstand prolonged periods of drought stress. Interestingly, despite impaired growth under standard growth conditions, photosynthetic efficiency recovers in pp7l mutant plants experiencing drought conditions. To assess the (post)transcriptional changes occurring in the pp7l mutant under different durations of drought exposure, we used an RNA-sequencing technique that allows the simultaneous detection of organellar and nuclear transcripts. Compared with the previously reported drought-responsive changes in the wild type, the drought-responsive changes in organellar and nuclear transcripts detected in the pp7l mutant were negligible. Our analysis of the data generated in this study and review and analysis of previous literature motivated us to create a pp7l hda6 (histone deacetylase 6) mutant, which exhibits remarkable drought resistance. Notably, the growth penalty associated with pp7l was alleviated in the double mutant, ruling out a dwarf effect on the drought-tolerant trait of this genotype. Future studies may consider that multiple loci and factors are involved in stress resistance and explore combinations of these factors to create even more resilient plants.
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Affiliation(s)
| | | | - Tatjana Kleine
- Plant Molecular Biology, Faculty of Biology, Ludwig-Maximilians-University Munich, Planegg-Martinsried, Germany
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Martins J, Neves M, Canhoto J. Drought-Stress-Induced Changes in Chloroplast Gene Expression in Two Contrasting Strawberry Tree ( Arbutus unedo L.) Genotypes. PLANTS (BASEL, SWITZERLAND) 2023; 12:4133. [PMID: 38140460 PMCID: PMC10747485 DOI: 10.3390/plants12244133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 12/04/2023] [Accepted: 12/08/2023] [Indexed: 12/24/2023]
Abstract
This study investigated the effect of drought stress on the expression of chloroplast genes in two different genotypes (A1 and A4) of strawberry tree plants with contrasting performances. Two-year-old plants were subjected to drought (20 days at 18% field capacity), and the photosynthetic activity, chlorophyll content, and expression levels of 16 chloroplast genes involved in photosynthesis and metabolism-related enzymes were analyzed. Genotype-specific responses were prominent, with A1 displaying wilting and leaf curling, contrasting with the mild symptoms observed in A4. Quantification of damage using the net CO2 assimilation rates and chlorophyll content unveiled a significant reduction in A1, while A4 maintained stability. Gene expression analysis revealed substantial downregulation of A1 (15 out of 16 genes) and upregulation of A4 (14 out of 16 genes). Notably, psbC was downregulated in A1, while it was prominently upregulated in A4. Principal Component Analysis (PCA) highlighted genotype-specific clusters, emphasizing distinct responses under stress, whereas a correlation analysis elucidated intricate relationships between gene expression, net CO2 assimilation, and chlorophyll content. Particularly, a positive correlation with psaB, whereas a negative correlation with psbC was found in genotype A1. Regression analysis identified potential predictors for net CO2 assimilation, in particular psaB. These findings contribute valuable insights for future strategies targeting crop enhancement and stress resilience, highlighting the central role of chloroplasts in orchestrating plant responses to environmental stressors, and may contribute to the development of drought-tolerant plant varieties, which are essential for sustaining agriculture in regions affected by water scarcity.
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Affiliation(s)
- João Martins
- Centre for Functional Ecology, Associate Laboratory TERRA, Department of Life Sciences, University of Coimbra, Calçada Martim de Freitas, 3000-456 Coimbra, Portugal; (M.N.); (J.C.)
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