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Xiong H, Luo Y, Zhao H, Wang J, Hu B, Yan C, Yao T, Zhang Y, Shi X, Rennenberg H. Integrated proteome and physiological traits reveal interactive mechanisms of new leaf growth and storage protein degradation with mature leaves of evergreen citrus trees. Tree Physiol 2024; 44:tpae001. [PMID: 38195893 DOI: 10.1093/treephys/tpae001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Accepted: 12/29/2023] [Indexed: 01/11/2024]
Abstract
The growth of fruit trees depends on the nitrogen (N) remobilization in mature tissues and N acquisition from the soil. However, in evergreen mature citrus (Citrus reticulata Blanco) leaves, proteins with N storage functions and hub molecules involved in driving N remobilization remain largely unknown. Here, we combined proteome and physiological analyses to characterize the spatiotemporal mechanisms of growth of new leaves and storage protein degradation in mature leaves of citrus trees exposed to low-N and high-N fertilization in the field. Results show that the growth of new leaves is driven by remobilization of stored reserves, rather than N uptake by the roots. In this context, proline and arginine in mature leaves acted as N sources supporting the growth of new leaves in spring. Time-series analyses with gel electrophoresis and proteome analysis indicated that the mature autumn shoot leaves are probably the sites of storage protein synthesis, while the aspartic endopeptidase protein is related to the degradation of storage proteins in mature citrus leaves. Furthermore, bioinformatic analysis based on protein-protein interactions indicated that glutamate synthetase and ATP-citrate synthetase are hub proteins in N remobilization from mature citrus leaves. These results provide strong physiological data for seasonal optimization of N fertilizer application in citrus orchards.
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Affiliation(s)
- Huaye Xiong
- Center of Molecular Ecophysiology (CMEP), College of Resources and Environment, Southwest University, No. 2, Tiansheng Road, Beibei District, 400715 Chongqing, P.R. China
| | - Yayin Luo
- Center of Molecular Ecophysiology (CMEP), College of Resources and Environment, Southwest University, No. 2, Tiansheng Road, Beibei District, 400715 Chongqing, P.R. China
| | - Huanyu Zhao
- Interdisciplinary Research Center for Agriculture Green Development in Yangtze River Basin, College of Resources and Environment, Southwest University, No. 2, Tiansheng Road, Beibei District, 400715 Chongqing, P.R. China
| | - Jie Wang
- Interdisciplinary Research Center for Agriculture Green Development in Yangtze River Basin, College of Resources and Environment, Southwest University, No. 2, Tiansheng Road, Beibei District, 400715 Chongqing, P.R. China
| | - Bin Hu
- Center of Molecular Ecophysiology (CMEP), College of Resources and Environment, Southwest University, No. 2, Tiansheng Road, Beibei District, 400715 Chongqing, P.R. China
| | - Chengquan Yan
- Citrus Research Institute, Southwest University, Xiema, Beibei District, 400712 Chongqing, P.R. China
| | - Tingshan Yao
- Citrus Research Institute, Southwest University, Xiema, Beibei District, 400712 Chongqing, P.R. China
| | - Yueqiang Zhang
- Interdisciplinary Research Center for Agriculture Green Development in Yangtze River Basin, College of Resources and Environment, Southwest University, No. 2, Tiansheng Road, Beibei District, 400715 Chongqing, P.R. China
| | - Xiaojun Shi
- Interdisciplinary Research Center for Agriculture Green Development in Yangtze River Basin, College of Resources and Environment, Southwest University, No. 2, Tiansheng Road, Beibei District, 400715 Chongqing, P.R. China
| | - Heinz Rennenberg
- Center of Molecular Ecophysiology (CMEP), College of Resources and Environment, Southwest University, No. 2, Tiansheng Road, Beibei District, 400715 Chongqing, P.R. China
- Chair of Tree Physiology, Institute of Forest Sciences, Albert-Ludwigs-Universität Freiburg, Georges-Köhler-Allee 53/54, 79110 Freiburg, Germany
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Tang M, Li Z, Luo L, Cheng B, Zhang Y, Zeng W, Peng Y. Nitric Oxide Signal, Nitrogen Metabolism, and Water Balance Affected by γ-Aminobutyric Acid (GABA) in Relation to Enhanced Tolerance to Water Stress in Creeping Bentgrass. Int J Mol Sci 2020; 21:E7460. [PMID: 33050389 PMCID: PMC7589152 DOI: 10.3390/ijms21207460] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 09/28/2020] [Accepted: 10/06/2020] [Indexed: 11/17/2022] Open
Abstract
γ-Aminobutyric acid (GABA) plays an important role in regulating stress tolerance in plants. Purposes of this study was to determine the effect of an exogenous supply of GABA on tolerance to water stress in creeping bentgrass (Agrostis stolonifera), and further reveal the GABA-induced key mechanisms related to water balance, nitrogen (N) metabolism and nitric oxide (NO) production in response to water stress. Plants were pretreated with or without 0.5 mM GABA solution in the roots for 3 days, and then subjected to water stress induced by -0.52 MPa polyethylene glycol 6000 for 12 days. The results showed that water stress caused leaf water deficit, chlorophyll (Chl) loss, oxidative damage (increases in superoxide anion, hydrogen peroxide, malondialdehyde, and protein carbonyl content), N insufficiency, and metabolic disturbance. However, the exogenous addition of GABA significantly increased endogenous GABA content, osmotic adjustment and antioxidant enzyme activities (superoxide dismutase, catalase, dehydroascorbate reductase, glutathione reductase and monodehydroascorbate reductase), followed by effectively alleviating water stress damage, including declines in oxidative damage, photoinhibition, and water and Chl loss. GABA supply not only provided more available N, but also affected N metabolism through activating nitrite reductase and glutamine synthetase activities under water stress. The supply of GABA did not increase glutamate content and glutamate decarboxylase activity, but enhanced glutamate dehydrogenase activity, which might indicate that GABA promoted the conversion and utilization of glutamate for maintaining Chl synthesis and tricarboxylic acid cycle when creeping bentgrass underwent water stress. In addition, GABA-induced NO production, depending on nitrate reductase and NO-associated protein pathways, could be associated with the enhancement of antioxidant defense. Current findings reveal the critical role of GABA in regulating signal transduction and metabolic homeostasis in plants under water-limited condition.
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Affiliation(s)
- Mingyan Tang
- Department of Grassland Science, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu 611130, China; (M.T.); (L.L.); (B.C.); (Y.Z.); (W.Z.); (Y.P.)
| | - Zhou Li
- Department of Grassland Science, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu 611130, China; (M.T.); (L.L.); (B.C.); (Y.Z.); (W.Z.); (Y.P.)
- Institute of Turfgrass Science, Beijing Forestry University, Beijing 100083, China
| | - Ling Luo
- Department of Grassland Science, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu 611130, China; (M.T.); (L.L.); (B.C.); (Y.Z.); (W.Z.); (Y.P.)
| | - Bizhen Cheng
- Department of Grassland Science, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu 611130, China; (M.T.); (L.L.); (B.C.); (Y.Z.); (W.Z.); (Y.P.)
| | - Youzhi Zhang
- Department of Grassland Science, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu 611130, China; (M.T.); (L.L.); (B.C.); (Y.Z.); (W.Z.); (Y.P.)
| | - Weihang Zeng
- Department of Grassland Science, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu 611130, China; (M.T.); (L.L.); (B.C.); (Y.Z.); (W.Z.); (Y.P.)
| | - Yan Peng
- Department of Grassland Science, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu 611130, China; (M.T.); (L.L.); (B.C.); (Y.Z.); (W.Z.); (Y.P.)
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Ahn CS, Lee HS, Pai HS. Molecular functions of the PP2A regulatory subunit Tap46 in plants. Plant Signal Behav 2011; 6:1067-8. [PMID: 21597327 PMCID: PMC3257798 DOI: 10.4161/psb.6.7.15651] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2011] [Accepted: 03/29/2011] [Indexed: 05/29/2023]
Abstract
Tap42/α4 is a regulatory subunit of the protein phosphatase 2A (PP2A) family of phosphatases and plays a role in the target of rapamycin (TOR) pathway that regulates cell growth, ribosome biogenesis, translation and cell cycle progression in both yeast and mammals. We determined the cellular functions of Tap46, the plant homolog of Tap42/α4, in both Arabidopsis thaliana and Nicotiana benthamiana. Tap46 associated with the catalytic subunits of PP2A and the PP2A-like phosphatases PP4 and PP6 in vivo. Tap46 was phosphorylated by TOR in vitro, indicating that Tap46 is a direct substrate of TOR kinase. Tap46 deficiency caused cellular phenotypes that are similar to TOR-depletion phenotypes, including repression of global translation and activation of both autophagy and nitrogen recycling. Furthermore, Tap46 depletion regulated total PP2A activity in a time-dependent manner similar to TOR deficiency. These results suggest that Tap46 acts as a positive effector of the TOR signaling pathway in controlling diverse metabolic processes in plants. However, Tap46 silencing caused acute cell death, while TOR silencing only hastened senescence. Furthermore, mitotic cells with reduced Tap46 levels exhibited chromatin bridges at anaphase, while TOR depletion did not cause a similar defect. These findings suggest that Tap46 may have TOR-independent functions as well as functions related to TOR signaling in plants.
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Kerley SJ, Read DJ. The biology of mycorrhiza in the Ericaceae: XIX. Fungal mycelium as a nitrogen source for the ericoid mycorrhizal fungus Hymenoscyphus ericae and its host plants. New Phytol 1997; 136:691-701. [PMID: 33863105 DOI: 10.1046/j.1469-8137.1997.00778.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Measurements of the chitin content of the rooting horizons of a typical mor-humus heathland soil, indicate that chitin can contain in excess of 20% of the total nitrogen in the litter (L) horizon and 30% in the fermentation (F) horizon. Much of this chitin-nitrogen is thought to be contained in the mycelial walls of soil fungi. Experiments were therefore designed to test the hypothesis that such sources of N could be rendered accessible to the ericaceous plants by their fungal endophytes. Mycelium of the ericoid endophyte Hymenoscyphus ericae (Read) Korf & Kernan and of the ectomycorrhizal fungus Suillus bovinus (Fr.) O. Krantze were grown in liquid culture before being killed and added either in the intact condition, or after fractionation, as sole sources of N to sterile media upon which were grown H. ericae in pure culture, or mycorrhizal and non-mycorrhizal plants of Vaccinium macrocarpon Ait. and Calluna vulgaris L. The abilities of the test organisms to utilize the nitrogen contained in the intact mycelial necromass, or in its fractions, were assessed by determining their yields and nitrogen concentrations of their tissues. It was revealed that H. ericae was able to produce significantly higher yield when grown on intact fungal necromass than when provided with equivalent concentrations of N in the form of ammonium. Its yields on mycelial fractions were lower, but still significantly greater than those obtained in the controls lacking N. Significantly greater yields and N contents were also found in the ericaceous plants grown with these nitrogenous substrates in the mycorrhizal condition. Without H. ericae they had no access to the substrates. The possible ecological implications of these results are discussed.
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Affiliation(s)
- Simon J Kerley
- Department of Animal and Plant Sciences, The University of Sheffield, Sheffield, S10 2TN, UK
| | - David J Read
- Department of Animal and Plant Sciences, The University of Sheffield, Sheffield, S10 2TN, UK
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