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Grover S, Mou DF, Shrestha K, Puri H, Pingault L, Sattler SE, Louis J. Impaired Brown midrib12 function orchestrates sorghum resistance to aphids via an auxin conjugate indole-3-acetic acid-aspartic acid. THE NEW PHYTOLOGIST 2024. [PMID: 39233513 DOI: 10.1111/nph.20091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Accepted: 08/08/2024] [Indexed: 09/06/2024]
Abstract
Lignin, a complex heterogenous polymer present in virtually all plant cell walls, plays a critical role in protecting plants from various stresses. However, little is known about how lignin modifications in sorghum will impact plant defense against sugarcane aphids (SCA), a key pest of sorghum. We utilized the sorghum brown midrib (bmr) mutants, which are impaired in monolignol synthesis, to understand sorghum defense mechanisms against SCA. We found that loss of Bmr12 function and overexpression (OE) of Bmr12 provided enhanced resistance and susceptibility to SCA, respectively, as compared with wild-type (WT; RTx430) plants. Monitoring of the aphid feeding behavior indicated that SCA spent more time in reaching the first sieve element phase on bmr12 plants compared with RTx430 and Bmr12-OE plants. A combination of transcriptomic and metabolomic analyses revealed that bmr12 plants displayed altered auxin metabolism upon SCA infestation and specifically, elevated levels of auxin conjugate indole-3-acetic acid-aspartic acid (IAA-Asp) were observed in bmr12 plants compared with RTx430 and Bmr12-OE plants. Furthermore, exogenous application of IAA-Asp restored resistance in Bmr12-OE plants, and artificial diet aphid feeding trial bioassays revealed that IAA-Asp is associated with enhanced resistance to SCA. Our findings highlight the molecular underpinnings that contribute to sorghum bmr12-mediated resistance to SCA.
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Affiliation(s)
- Sajjan Grover
- Department of Entomology, University of Nebraska-Lincoln, Lincoln, NE, 68583, USA
| | - De-Fen Mou
- Department of Entomology, University of Nebraska-Lincoln, Lincoln, NE, 68583, USA
| | - Kumar Shrestha
- Department of Entomology, University of Nebraska-Lincoln, Lincoln, NE, 68583, USA
| | - Heena Puri
- Department of Entomology, University of Nebraska-Lincoln, Lincoln, NE, 68583, USA
| | - Lise Pingault
- Department of Entomology, University of Nebraska-Lincoln, Lincoln, NE, 68583, USA
| | - Scott E Sattler
- Wheat, Sorghum, and Forage Research Unit, U.S. Department of Agriculture-Agricultural Research Service, Lincoln, NE, 68583, USA
| | - Joe Louis
- Department of Entomology, University of Nebraska-Lincoln, Lincoln, NE, 68583, USA
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE, 68583, USA
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Rosati VC, Quinn AA, Gleadow RM, Blomstedt CK. The Putative GATA Transcription Factor SbGATA22 as a Novel Regulator of Dhurrin Biosynthesis. Life (Basel) 2024; 14:470. [PMID: 38672741 PMCID: PMC11051066 DOI: 10.3390/life14040470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Revised: 03/21/2024] [Accepted: 04/02/2024] [Indexed: 04/28/2024] Open
Abstract
Cyanogenic glucosides are specialized metabolites produced by over 3000 species of higher plants from more than 130 families. The deployment of cyanogenic glucosides is influenced by biotic and abiotic factors in addition to being developmentally regulated, consistent with their roles in plant defense and stress mitigation. Despite their ubiquity, very little is known regarding the molecular mechanisms that regulate their biosynthesis. The biosynthetic pathway of dhurrin, the cyanogenic glucoside found in the important cereal crop sorghum (Sorghum bicolor (L.) Moench), was described over 20 years ago, and yet no direct regulator of the biosynthetic genes has been identified. To isolate regulatory proteins that bind to the promoter region of the key dhurrin biosynthetic gene of sorghum, SbCYP79A1, yeast one-hybrid screens were performed. A bait fragment containing 1204 base pairs of the SbCYP79A1 5' regulatory region was cloned upstream of a reporter gene and introduced into Saccharomyces cerevisiae. Subsequently, the yeast was transformed with library cDNA representing RNA from two different sorghum developmental stages. From these screens, we identified SbGATA22, an LLM domain B-GATA transcription factor that binds to the putative GATA transcription factor binding motifs in the SbCYP79A1 promoter region. Transient assays in Nicotiana benthamiana show that SbGATA22 localizes to the nucleus. The expression of SbGATA22, in comparison with SbCYP79A1 expression and dhurrin concentration, was analyzed over 14 days of sorghum development and in response to nitrogen application, as these conditions are known to affect dhurrin levels. Collectively, these findings suggest that SbGATA22 may act as a negative regulator of SbCYP79A1 expression and provide a preliminary insight into the molecular regulation of dhurrin biosynthesis in sorghum.
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Affiliation(s)
- Viviana C. Rosati
- School of Biological Sciences, Monash University, Wellington Road, Clayton, VIC 3800, Australia; (V.C.R.); (A.A.Q.); (R.M.G.)
| | - Alicia A. Quinn
- School of Biological Sciences, Monash University, Wellington Road, Clayton, VIC 3800, Australia; (V.C.R.); (A.A.Q.); (R.M.G.)
| | - Roslyn M. Gleadow
- School of Biological Sciences, Monash University, Wellington Road, Clayton, VIC 3800, Australia; (V.C.R.); (A.A.Q.); (R.M.G.)
- Queensland Alliance for Agriculture & Food Innovation, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Cecilia K. Blomstedt
- School of Biological Sciences, Monash University, Wellington Road, Clayton, VIC 3800, Australia; (V.C.R.); (A.A.Q.); (R.M.G.)
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Boter M, Diaz I. Cyanogenesis, a Plant Defence Strategy against Herbivores. Int J Mol Sci 2023; 24:ijms24086982. [PMID: 37108149 PMCID: PMC10138981 DOI: 10.3390/ijms24086982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 03/29/2023] [Accepted: 04/03/2023] [Indexed: 04/29/2023] Open
Abstract
Plants and phytophagous arthropods have coevolved in a long battle for survival. Plants respond to phytophagous feeders by producing a battery of antiherbivore chemical defences, while herbivores try to adapt to their hosts by attenuating the toxic effect of the defence compounds. Cyanogenic glucosides are a widespread group of defence chemicals that come from cyanogenic plants. Among the non-cyanogenic ones, the Brassicaceae family has evolved an alternative cyanogenic pathway to produce cyanohydrin as a way to expand defences. When a plant tissue is disrupted by an herbivore attack, cyanogenic substrates are brought into contact with degrading enzymes that cause the release of toxic hydrogen cyanide and derived carbonyl compounds. In this review, we focus our attention on the plant metabolic pathways linked to cyanogenesis to generate cyanide. It also highlights the role of cyanogenesis as a key defence mechanism of plants to fight against herbivore arthropods, and we discuss the potential of cyanogenesis-derived molecules as alternative strategies for pest control.
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Affiliation(s)
- Marta Boter
- Centro de Biotecnología y Genómica de Plantas (CBGP), Universidad Politécnica de Madrid (UPM)-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA/CSIC), Campus de Montegancedo, 20223 Madrid, Spain
| | - Isabel Diaz
- Centro de Biotecnología y Genómica de Plantas (CBGP), Universidad Politécnica de Madrid (UPM)-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA/CSIC), Campus de Montegancedo, 20223 Madrid, Spain
- Departamento de Biotecnología-Biología Vegetal, Escuela Técnica Superior de Ingeniería Agronómica, Alimentaria y de Biosistemas, Universidad Politécnica de Madrid (UPM), 28040 Madrid, Spain
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Liu H, Micic N, Miller S, Crocoll C, Bjarnholt N. Species-specific dynamics of specialized metabolism in germinating sorghum grain revealed by temporal and tissue-resolved transcriptomics and metabolomics. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2023; 196:807-820. [PMID: 36863218 DOI: 10.1016/j.plaphy.2023.02.031] [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: 10/02/2022] [Revised: 02/12/2023] [Accepted: 02/14/2023] [Indexed: 06/19/2023]
Abstract
Seed germination is crucial for plant productivity, and the biochemical changes during germination affect seedling survival, plant health and yield. While the general metabolism of germination is extensively studied, the role of specialized metabolism is less investigated. We therefore analyzed the metabolism of the defense compound dhurrin during sorghum (Sorghum bicolor) grain germination and early seedling development. Dhurrin is a cyanogenic glucoside, which is catabolized into different bioactive compounds at other stages of plant development, but its fate and role during germination is unknown. We dissected sorghum grain into three different tissues and investigated dhurrin biosynthesis and catabolism at the transcriptomic, metabolomic and biochemical level. We further analyzed transcriptional signature differences of cyanogenic glucoside metabolism between sorghum and barley (Hordeum vulgare), which produces similar specialized metabolites. We found that dhurrin is de novo biosynthesized and catabolized in the growing embryonic axis as well as the scutellum and aleurone layer, two tissues otherwise mainly acknowledged for their involvement in release and transport of general metabolites from the endosperm to the embryonic axis. In contrast, genes encoding cyanogenic glucoside biosynthesis in barley are exclusively expressed in the embryonic axis. Glutathione transferase enzymes (GSTs) are involved in dhurrin catabolism and the tissue-resolved analysis of GST expression identified new pathway candidate genes and conserved GSTs as potentially important in cereal germination. Our study demonstrates a highly dynamic tissue- and species-specific specialized metabolism during cereal grain germination, highlighting the importance of tissue-resolved analyses and identification of specific roles of specialized metabolites in fundamental plant processes.
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Affiliation(s)
- Huijun Liu
- Plant Biochemistry Laboratory, Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, 1871, Denmark; Copenhagen Plant Science Center, Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, 1871, Denmark.
| | - Nikola Micic
- Plant Biochemistry Laboratory, Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, 1871, Denmark; Copenhagen Plant Science Center, Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, 1871, Denmark.
| | - Sara Miller
- Plant Biochemistry Laboratory, Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, 1871, Denmark; Copenhagen Plant Science Center, Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, 1871, Denmark.
| | - Christoph Crocoll
- DynaMo Center, Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, 1871, Denmark.
| | - Nanna Bjarnholt
- Plant Biochemistry Laboratory, Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, 1871, Denmark; Copenhagen Plant Science Center, Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, 1871, Denmark.
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Yadav M, Singh IK, Singh A. Dhurrin: A naturally occurring phytochemical as a weapon against insect herbivores. PHYTOCHEMISTRY 2023; 205:113483. [PMID: 36279963 DOI: 10.1016/j.phytochem.2022.113483] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 10/18/2022] [Accepted: 10/19/2022] [Indexed: 06/16/2023]
Abstract
Dhurrin, a cyanogenic glucoside, is a plant defensive chemical synthesized from aliphatic amino acids and consists of β-d-glucopyranose linked to α-hydroxy nitrile. It is catabolized by the consecutive action of hydroxynitrilase and β-glucosidase to release hydrogen cyanide on tissue disruption during herbivory. These phytoanticipins are widely distributed across various monocot and dicot plants such as Sorghum, Macadamia, Ostrya sp., and many other plant species with ornamental, pharmaceutical, medicinal, and food value. Although repellent properties of dhurrin against herbivores are often reported, less is known about its distribution, metabolism, mode of action against insects, and application for pest control. Herein, we highlight recent updates on dhurrin distribution, biosynthesis, and catabolism along with the cyanide detoxification pathway. Additionally, this article focuses on biological activities of dhurrin against various herbivores and opportunities to explore the utilization of dhurrin as a natural pest control agent and a substitute for chemically synthesized pesticides.
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Affiliation(s)
- Manisha Yadav
- Department of Botany, Hansraj College, University of Delhi, Delhi, 110007, India
| | - Indrakant K Singh
- Molecular Biology Research Lab, Department of Zoology, Deshbandhu College, University of Delhi, Kalkaji, New Delhi, 110019, India.
| | - Archana Singh
- Department of Botany, Hansraj College, University of Delhi, Delhi, 110007, India; Delhi School of Climate Change and Sustainability, Institution of Eminence, Maharishi Karnad Bhawan, University of Delhi, Delhi, 110007, India.
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