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Govindan G, Harini P, Alphonse V, Parani M. From swamp to field: how genes from mangroves and its associates can enhance crop salinity tolerance. Mol Biol Rep 2024; 51:598. [PMID: 38683409 DOI: 10.1007/s11033-024-09539-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Accepted: 04/09/2024] [Indexed: 05/01/2024]
Abstract
Salinity stress is a critical challenge in crop production and requires innovative strategies to enhance the salt tolerance of plants. Insights from mangrove species, which are renowned for their adaptability to high-salinity environments, provides valuable genetic targets and resources for improving crops. A significant hurdle in salinity stress is the excessive uptake of sodium ions (Na+) by plant roots, causing disruptions in cellular balance, nutrient deficiencies, and hampered growth. Specific ion transporters and channels play crucial roles in maintaining a low Na+/K+ ratio in root cells which is pivotal for salt tolerance. The family of high-affinity potassium transporters, recently characterized in Avicennia officinalis, contributes to K+ homeostasis in transgenic Arabidopsis plants even under high-salt conditions. The salt overly sensitive pathway and genes related to vacuolar-type H+-ATPases hold promise for expelling cytosolic Na+ and sequestering Na+ in transgenic plants, respectively. Aquaporins contribute to mangroves' adaptation to saline environments by regulating water uptake, transpiration, and osmotic balance. Antioxidant enzymes mitigate oxidative damage, whereas genes regulating osmolytes, such as glycine betaine and proline, provide osmoprotection. Mangroves exhibit increased expression of stress-responsive transcription factors such as MYB, NAC, and CBFs under high salinity. Moreover, genes involved in various metabolic pathways, including jasmonate synthesis, triterpenoid production, and protein stability under salt stress, have been identified. This review highlights the potential of mangrove genes to enhance salt tolerance of crops. Further research is imperative to fully comprehend and apply these genes to crop breeding to improve salinity resilience.
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Affiliation(s)
- Ganesan Govindan
- Department of Genetic Engineering, SRM Institute of Science and Technology, Kattankulathur, TN, 603203, India
| | - Prakash Harini
- Department of Genetic Engineering, SRM Institute of Science and Technology, Kattankulathur, TN, 603203, India
| | - Vinoth Alphonse
- Department of Botany, St. Xavier's College (Autonomous), Palayamkottai, TN, 627 002, India
| | - Madasamy Parani
- Department of Genetic Engineering, SRM Institute of Science and Technology, Kattankulathur, TN, 603203, India.
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Chi BJ, Guo ZJ, Wei MY, Song SW, Zhong YH, Liu JW, Zhang YC, Li J, Xu CQ, Zhu XY, Zheng HL. Structural, developmental and functional analyses of leaf salt glands of mangrove recretohalophyte Aegiceras corniculatum. TREE PHYSIOLOGY 2024; 44:tpad123. [PMID: 37769324 DOI: 10.1093/treephys/tpad123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 07/27/2023] [Accepted: 09/26/2023] [Indexed: 09/30/2023]
Abstract
Salt secretion is an important strategy used by the mangrove plant Aegiceras corniculatum to adapt to the coastal intertidal environment. However, the structural, developmental and functional analyses on the leaf salt glands, particularly the salt secretion mechanism, are not well documented. In this study, we investigated the structural, developmental and degenerative characteristics and the salt secretion mechanisms of salt glands to further elucidate the mechanisms of salt tolerance of A. corniculatum. The results showed that the salt gland cells have a large number of mitochondria and vesicles, and plenty of plasmodesmata as well, while chloroplasts were found in the collecting cells. The salt glands developed early and began to differentiate at the leaf primordium stage. We observed and defined three stages of salt gland degradation for the first time in A. corniculatum, where the secretory cells gradually twisted and wrinkled inward and collapsed downward as the salt gland degeneration increased and the intensity of salt gland autofluorescence gradually diminished. In addition, we found that the salt secretion rate of the salt glands increased when the treated concentration of NaCl increased, reaching the maximum at 400 mM NaCl. The salt-secreting capacity of the salt glands of the adaxial epidermis is significantly greater than that of the abaxial epidermis. The real-time quantitative PCR results indicate that SAD2, TTG1, GL2 and RBR1 may be involved in regulating the development of the salt glands of A. corniculatum. Moreover, Na+/H+ antiporter, H+-ATPase, K+ channel and Cl- channel may play important roles in the salt secretion of salt glands. In sum mary, this study strengthens the understanding of the structural, developmental and degenerative patterns of salt glands and salt secretion mechanisms in mangrove recretohalophyte A. corniculatum, providing an important reference for further studies at the molecular level.
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Affiliation(s)
- Bing-Jie Chi
- Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, College of the Environment and Ecology, Xiamen University, Xiangan South Road, Xiangan district, Xiamen, Fujian 361102, P. R. China
| | - Ze-Jun Guo
- Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, College of the Environment and Ecology, Xiamen University, Xiangan South Road, Xiangan district, Xiamen, Fujian 361102, P. R. China
- Guangxi Laboratory on the Study of Coral Reefs in the South China Sea, Coral Reef Research Center of China, School of Marine Sciences, Guangxi University, 100 Daxue East Road, Nanning 530004, China
| | - Ming-Yue Wei
- Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, College of the Environment and Ecology, Xiamen University, Xiangan South Road, Xiangan district, Xiamen, Fujian 361102, P. R. China
- School of Ecology, Resources and Environment, Dezhou University, Dezhou, Shandong 253000, China
| | - Shi-Wei Song
- Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, College of the Environment and Ecology, Xiamen University, Xiangan South Road, Xiangan district, Xiamen, Fujian 361102, P. R. China
| | - You-Hui Zhong
- Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, College of the Environment and Ecology, Xiamen University, Xiangan South Road, Xiangan district, Xiamen, Fujian 361102, P. R. China
| | - Jing-Wen Liu
- Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, College of the Environment and Ecology, Xiamen University, Xiangan South Road, Xiangan district, Xiamen, Fujian 361102, P. R. China
| | - Yu-Chen Zhang
- Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, College of the Environment and Ecology, Xiamen University, Xiangan South Road, Xiangan district, Xiamen, Fujian 361102, P. R. China
| | - Jing Li
- Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, College of the Environment and Ecology, Xiamen University, Xiangan South Road, Xiangan district, Xiamen, Fujian 361102, P. R. China
| | - Chao-Qun Xu
- Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, College of the Environment and Ecology, Xiamen University, Xiangan South Road, Xiangan district, Xiamen, Fujian 361102, P. R. China
| | - Xue-Yi Zhu
- Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, College of the Environment and Ecology, Xiamen University, Xiangan South Road, Xiangan district, Xiamen, Fujian 361102, P. R. China
| | - Hai-Lei Zheng
- Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, College of the Environment and Ecology, Xiamen University, Xiangan South Road, Xiangan district, Xiamen, Fujian 361102, P. R. China
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De Rosa A, McGaughey S, Magrath I, Byrt C. Molecular membrane separation: plants inspire new technologies. THE NEW PHYTOLOGIST 2023; 238:33-54. [PMID: 36683439 DOI: 10.1111/nph.18762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2022] [Accepted: 01/06/2023] [Indexed: 06/17/2023]
Abstract
Plants draw up their surrounding soil solution to gain water and nutrients required for growth, development and reproduction. Obtaining adequate water and nutrients involves taking up both desired and undesired elements from the soil solution and separating resources from waste. Desirable and undesirable elements in the soil solution can share similar chemical properties, such as size and charge. Plants use membrane separation mechanisms to distinguish between different molecules that have similar chemical properties. Membrane separation enables distribution or retention of resources and efflux or compartmentation of waste. Plants use specialised membrane separation mechanisms to adapt to challenging soil solution compositions and distinguish between resources and waste. Coordination and regulation of these mechanisms between different tissues, cell types and subcellular membranes supports plant nutrition, environmental stress tolerance and energy management. This review considers membrane separation mechanisms in plants that contribute to specialised separation processes and highlights mechanisms of interest for engineering plants with enhanced performance in challenging conditions and for inspiring the development of novel industrial membrane separation technologies. Knowledge gained from studying plant membrane separation mechanisms can be applied to developing precision separation technologies. Separation technologies are needed for harvesting resources from industrial wastes and transitioning to a circular green economy.
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Affiliation(s)
- Annamaria De Rosa
- Division of Plant Science, Research School of Biology, Australian National University, 2601, ACT, Acton, Australia
| | - Samantha McGaughey
- Division of Plant Science, Research School of Biology, Australian National University, 2601, ACT, Acton, Australia
| | - Isobel Magrath
- Division of Plant Science, Research School of Biology, Australian National University, 2601, ACT, Acton, Australia
| | - Caitlin Byrt
- Division of Plant Science, Research School of Biology, Australian National University, 2601, ACT, Acton, Australia
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Zhao B, Zhou Y, Jiao X, Wang X, Wang B, Yuan F. Bracelet salt glands of the recretohalophyte Limonium bicolor: Distribution, morphology, and induction. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2023; 65:950-966. [PMID: 36453195 DOI: 10.1111/jipb.13417] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Accepted: 11/27/2022] [Indexed: 06/17/2023]
Abstract
Halophytes complete their life cycles in saline environments. The recretohalophyte Limonium bicolor has evolved a specialized salt secretory structure, the salt gland, which excretes Na+ to avoid salt damage. Typical L. bicolor salt glands consist of 16 cells with four fluorescent foci and four secretory pores. Here, we describe a special type of salt gland at the base of the L. bicolor leaf petiole named bracelet salt glands due to their beaded-bracelet-like shape of blue auto-fluorescence. Bracelet salt glands contain more than 16 cells and more than four secretory pores. Leaf disc secretion measurements and non-invasive micro-test techniques indicated that bracelet salt glands secrete more salt than normal salt glands, which helps maintain low Na+ levels at the leaf blade to protect the leaf. Cytokinin treatment induced bracelet salt gland differentiation, and the developed ones showed no further differentiation when traced with a living fluorescence microscopy imager, even though new salt gland development and leaf expansion were observed. Transcriptome revealed a NAC transcription factor gene that participates in bracelet salt gland development, as confirmed by its genome editing and overexpression in L. bicolor. These findings shed light on bracelet salt gland development and may facilitate the engineering of salt-tolerant crops.
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Affiliation(s)
- Boqing Zhao
- Shandong Provincial Key Laboratory of Plant Stress, College of Life Sciences, Shandong Normal University, Ji'nan, 250014, China
| | - Yingli Zhou
- Shandong Provincial Key Laboratory of Plant Stress, College of Life Sciences, Shandong Normal University, Ji'nan, 250014, China
| | - Xiangmei Jiao
- Shandong Provincial Key Laboratory of Plant Stress, College of Life Sciences, Shandong Normal University, Ji'nan, 250014, China
| | - Xi Wang
- Shandong Provincial Key Laboratory of Plant Stress, College of Life Sciences, Shandong Normal University, Ji'nan, 250014, China
| | - Baoshan Wang
- Shandong Provincial Key Laboratory of Plant Stress, College of Life Sciences, Shandong Normal University, Ji'nan, 250014, China
| | - Fang Yuan
- Shandong Provincial Key Laboratory of Plant Stress, College of Life Sciences, Shandong Normal University, Ji'nan, 250014, China
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Lu C, Yuan F, Guo J, Han G, Wang C, Chen M, Wang B. Current Understanding of Role of Vesicular Transport in Salt Secretion by Salt Glands in Recretohalophytes. Int J Mol Sci 2021; 22:2203. [PMID: 33672188 PMCID: PMC7926375 DOI: 10.3390/ijms22042203] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 02/17/2021] [Accepted: 02/19/2021] [Indexed: 12/18/2022] Open
Abstract
Soil salinization is a serious and growing problem around the world. Some plants, recognized as the recretohalophytes, can normally grow on saline-alkali soil without adverse effects by secreting excessive salt out of the body. The elucidation of the salt secretion process is of great significance for understanding the salt tolerance mechanism adopted by the recretohalophytes. Between the 1950s and the 1970s, three hypotheses, including the osmotic potential hypothesis, the transfer system similar to liquid flow in animals, and vesicle-mediated exocytosis, were proposed to explain the salt secretion process of plant salt glands. More recently, increasing evidence has indicated that vesicular transport plays vital roles in salt secretion of recretohalophytes. Here, we summarize recent findings, especially regarding the molecular evidence on the functional roles of vesicular trafficking in the salt secretion process of plant salt glands. A model of salt secretion in salt gland is also proposed.
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Affiliation(s)
| | | | | | | | | | | | - Baoshan Wang
- Shandong Provincial Key Laboratory of Plant Stress Research, College of Life Sciences, Shandong Normal University, Jinan 250014, China; (C.L.); (F.Y.); (J.G.); (G.H.); (C.W.); (M.C.)
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Dassanayake M, Larkin JC. Making Plants Break a Sweat: the Structure, Function, and Evolution of Plant Salt Glands. FRONTIERS IN PLANT SCIENCE 2017; 8:406. [PMID: 28400779 PMCID: PMC5368257 DOI: 10.3389/fpls.2017.00406] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Accepted: 03/09/2017] [Indexed: 05/25/2023]
Abstract
Salt stress is a complex trait that poses a grand challenge in developing new crops better adapted to saline environments. Some plants, called recretohalophytes, that have naturally evolved to secrete excess salts through salt glands, offer an underexplored genetic resource for examining how plant development, anatomy, and physiology integrate to prevent excess salt from building up to toxic levels in plant tissue. In this review we examine the structure and evolution of salt glands, salt gland-specific gene expression, and the possibility that all salt glands have originated via evolutionary modifications of trichomes. Salt secretion via salt glands is found in more than 50 species in 14 angiosperm families distributed in caryophyllales, asterids, rosids, and grasses. The salt glands of these distantly related clades can be grouped into four structural classes. Although salt glands appear to have originated independently at least 12 times, they share convergently evolved features that facilitate salt compartmentalization and excretion. We review the structural diversity and evolution of salt glands, major transporters and proteins associated with salt transport and secretion in halophytes, salt gland relevant gene expression regulation, and the prospect for using new genomic and transcriptomic tools in combination with information from model organisms to better understand how salt glands contribute to salt tolerance. Finally, we consider the prospects for using this knowledge to engineer salt glands to increase salt tolerance in model species, and ultimately in crops.
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Affiliation(s)
- Maheshi Dassanayake
- Department of Biological Sciences, Louisiana State University, Baton RougeLA, USA
| | - John C. Larkin
- Department of Biological Sciences, Louisiana State University, Baton RougeLA, USA
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Yuan F, Leng B, Wang B. Progress in Studying Salt Secretion from the Salt Glands in Recretohalophytes: How Do Plants Secrete Salt? FRONTIERS IN PLANT SCIENCE 2016; 7:977. [PMID: 27446195 PMCID: PMC4927796 DOI: 10.3389/fpls.2016.00977] [Citation(s) in RCA: 142] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Accepted: 06/20/2016] [Indexed: 05/18/2023]
Abstract
To survive in a saline environment, halophytes have evolved many strategies to resist salt stress. The salt glands of recretohalophytes are exceptional features for directly secreting salt out of a plant. Knowledge of the pathway(s) of salt secretion in relation to the function of salt glands may help us to change the salt-tolerance of crops and to cultivate the extensive saline lands that are available. Recently, ultrastructural studies of salt glands and the mechanism of salt secretion, particularly the candidate genes involved in salt secretion, have been illustrated in detail. In this review, we summarize current researches on salt gland structure, salt secretion mechanism and candidate genes involved, and provide an overview of the salt secretion pathway and the asymmetric ion transport of the salt gland. A new model recretohalophyte is also proposed.
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Affiliation(s)
| | | | - Baoshan Wang
- Key Lab of Plant Stress Research, College of Life Science, Shandong Normal UniversityJi’nan, China
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