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Huizinga S, Bouwmeester HJ. Role of Strigolactones in the Host Specificity of Broomrapes and Witchweeds. PLANT & CELL PHYSIOLOGY 2023; 64:936-954. [PMID: 37319019 PMCID: PMC10504575 DOI: 10.1093/pcp/pcad058] [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: 05/11/2023] [Revised: 06/05/2023] [Accepted: 06/14/2023] [Indexed: 06/17/2023]
Abstract
Root parasitic plants of the Orobanchaceae, broomrapes and witchweeds, pose a severe problem to agriculture in Europe, Asia and especially Africa. These parasites are totally dependent on their host for survival, and therefore, their germination is tightly regulated by host presence. Indeed, their seeds remain dormant in the soil until a host root is detected through compounds called germination stimulants. Strigolactones (SLs) are the most important class of germination stimulants. They play an important role in planta as a phytohormone and, upon exudation from the root, function in the recruitment of symbiotic arbuscular mycorrhizal fungi. Plants exude mixtures of various different SLs, possibly to evade detection by these parasites and still recruit symbionts. Vice versa, parasitic plants must only respond to the SL composition that is exuded by their host, or else risk germination in the presence of non-hosts. Therefore, parasitic plants have evolved an entire clade of SL receptors, called HTL/KAI2s, to perceive the SL cues. It has been demonstrated that these receptors each have a distinct sensitivity and specificity to the different known SLs, which possibly allows them to recognize the SL-blend characteristic of their host. In this review, we will discuss the molecular basis of SL sensitivity and specificity in these parasitic plants through HTL/KAI2s and review the evidence that these receptors contribute to host specificity of parasitic plants.
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Affiliation(s)
- Sjors Huizinga
- Plant Hormone Biology Group, Green Life Sciences Cluster, Swammerdam Institute for Life Science, University of Amsterdam, Science Park 904, Amsterdam 1098 XH, The Netherlands
| | - Harro J Bouwmeester
- Plant Hormone Biology Group, Green Life Sciences Cluster, Swammerdam Institute for Life Science, University of Amsterdam, Science Park 904, Amsterdam 1098 XH, The Netherlands
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Probing strigolactone perception mechanisms with rationally designed small-molecule agonists stimulating germination of root parasitic weeds. Nat Commun 2022; 13:3987. [PMID: 35810153 PMCID: PMC9271048 DOI: 10.1038/s41467-022-31710-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Accepted: 06/29/2022] [Indexed: 01/11/2023] Open
Abstract
The development of potent strigolactone (SL) agonists as suicidal germination inducers could be a useful strategy for controlling root parasitic weeds, but uncertainty about the SL perception mechanism impedes real progress. Here we describe small-molecule agonists that efficiently stimulate Phelipanchce aegyptiaca, and Striga hermonthica, germination in concentrations as low as 10−8 to 10−17 M. We show that full efficiency of synthetic SL agonists in triggering signaling through the Striga SL receptor, ShHTL7, depends on the receptor-catalyzed hydrolytic reaction of the agonists. Additionally, we reveal that the stereochemistry of synthetic SL analogs affects the hydrolytic ability of ShHTL7 by influencing the probability of the privileged conformations of ShHTL7. Importantly, an alternative ShHTL7-mediated hydrolysis mechanism, proceeding via nucleophilic attack of the NE2 atom of H246 to the 2′C of the D-ring, is reported. Together, our findings provide insight into SL hydrolysis and structure-perception mechanisms, and potent suicide germination stimulants, which would contribute to the elimination of the noxious parasitic weeds. Strigolactone agonists could potentially help control noxious weeds by promoting suicidal germination. Here the authors describe a series of small molecule agonists that stimulate germination via the Striga ShHTL7 receptor and show that stereochemistry and hydrolysis-independent signalling mediate potency.
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White ARF, Mendez JA, Khosla A, Nelson DC. Rapid analysis of strigolactone receptor activity in a Nicotiana benthamiana dwarf14 mutant. PLANT DIRECT 2022; 6:e389. [PMID: 35355884 PMCID: PMC8948499 DOI: 10.1002/pld3.389] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 12/03/2021] [Accepted: 02/17/2022] [Indexed: 05/29/2023]
Abstract
DWARF14 (D14) is an ɑ/β-hydrolase and receptor for the plant hormone strigolactone (SL) in angiosperms. Upon SL perception, D14 works with MORE AXILLARY GROWTH2 (MAX2) to trigger polyubiquitination and degradation of DWARF53(D53)-type proteins in the SUPPRESSOR OF MAX2 1-LIKE (SMXL) family. We used CRISPR-Cas9 to generate knockout alleles of the two homoeologous D14 genes in the Nicotiana benthamiana genome. The Nbd14a,b double mutant had several phenotypes that are consistent with the loss of SL perception in other plants, including increased axillary bud outgrowth, reduced height, shortened petioles, and smaller leaves. A ratiometric fluorescent reporter system was used to monitor degradation of SMXL7 from Arabidopsis thaliana (AtSMXL7) after transient expression in N. benthamiana and treatment with the strigolactone analog GR24. AtSMXL7 was degraded after treatment with GR245DS, which has the stereochemical configuration of natural SLs, as well as its enantiomer GR24 ent-5DS. In Nbd14a,b leaves, AtSMXL7 abundance was unaffected by rac-GR24 or either GR24 stereoisomer. Transient coexpression of AtD14 with the AtSMXL7 reporter in Nbd14a,b restored the degradation response to rac-GR24, but required an active catalytic triad. We used this platform to evaluate the ability of several AtD14 mutants that had not been characterized in plants to target AtSMXL7 for degradation.
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Affiliation(s)
- Alexandra R. F. White
- Department of Botany and Plant SciencesUniversity of CaliforniaRiversideCaliforniaUSA
| | - Jose A. Mendez
- Department of Botany and Plant SciencesUniversity of CaliforniaRiversideCaliforniaUSA
| | - Aashima Khosla
- Department of Botany and Plant SciencesUniversity of CaliforniaRiversideCaliforniaUSA
| | - David C. Nelson
- Department of Botany and Plant SciencesUniversity of CaliforniaRiversideCaliforniaUSA
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Krasylenko Y, Komis G, Hlynska S, Vavrdová T, Ovečka M, Pospíšil T, Šamaj J. GR24, A Synthetic Strigolactone Analog, and Light Affect the Organization of Cortical Microtubules in Arabidopsis Hypocotyl Cells. FRONTIERS IN PLANT SCIENCE 2021; 12:675981. [PMID: 34305975 PMCID: PMC8293678 DOI: 10.3389/fpls.2021.675981] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 05/06/2021] [Indexed: 06/01/2023]
Abstract
Strigolactones are plant hormones regulating cytoskeleton-mediated developmental events in roots, such as lateral root formation and elongation of root hairs and hypocotyls. The latter process was addressed herein by the exogenous application of a synthetic strigolactone, GR24, and an inhibitor of strigolactone biosynthesis, TIS108, on hypocotyls of wild-type Arabidopsis and a strigolactone signaling mutant max2-1 (more axillary growth 2-1). Owing to the interdependence between light and strigolactone signaling, the present work was extended to seedlings grown under a standard light/dark regime, or under continuous darkness. Given the essential role of the cortical microtubules in cell elongation, their organization and dynamics were characterized under the conditions of altered strigolactone signaling using fluorescence microscopy methods with different spatiotemporal capacities, such as confocal laser scanning microscopy (CLSM) and structured illumination microscopy (SIM). It was found that GR24-dependent inhibition of hypocotyl elongation correlated with changes in cortical microtubule organization and dynamics, observed in living wild-type and max2-1 seedlings stably expressing genetically encoded fluorescent molecular markers for microtubules. Quantitative assessment of microscopic datasets revealed that chemical and/or genetic manipulation of strigolactone signaling affected microtubule remodeling, especially under light conditions. The application of GR24 in dark conditions partially alleviated cytoskeletal rearrangement, suggesting a new mechanistic connection between cytoskeletal behavior and the light-dependence of strigolactone signaling.
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Affiliation(s)
- Yuliya Krasylenko
- Department of Cell Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University Olomouc, Olomouc, Czechia
| | - George Komis
- Department of Cell Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University Olomouc, Olomouc, Czechia
| | - Sofiia Hlynska
- Department of Cell Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University Olomouc, Olomouc, Czechia
| | - Tereza Vavrdová
- Department of Cell Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University Olomouc, Olomouc, Czechia
| | - Miroslav Ovečka
- Department of Cell Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University Olomouc, Olomouc, Czechia
| | - Tomáš Pospíšil
- Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University Olomouc, Olomouc, Czechia
| | - Jozef Šamaj
- Department of Cell Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University Olomouc, Olomouc, Czechia
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Wang Y, Yao R, Du X, Guo L, Chen L, Xie D, Smith SM. Molecular basis for high ligand sensitivity and selectivity of strigolactone receptors in Striga. PLANT PHYSIOLOGY 2021; 185:1411-1428. [PMID: 33793945 PMCID: PMC8133601 DOI: 10.1093/plphys/kiaa048] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Accepted: 11/11/2020] [Indexed: 05/30/2023]
Abstract
Seeds of the root parasitic plant Striga hermonthica can sense very low concentrations of strigolactones (SLs) exuded from host roots. The S. hermonthica hyposensitive to light (ShHTL) proteins are putative SL receptors, among which ShHTL7 reportedly confers sensitivity to picomolar levels of SL when expressed in Arabidopsis thaliana. However, the molecular mechanism underlying ShHTL7 sensitivity is unknown. Here we determined the ShHTL7 crystal structure and quantified its interactions with various SLs and key interacting proteins. We established that ShHTL7 has an active-site pocket with broad-spectrum response to different SLs and moderate affinity. However, in contrast to other ShHTLs, we observed particularly high affinity of ShHTL7 for F-box protein AtMAX2. Furthermore, ShHTL7 interacted with AtMAX2 and with transcriptional regulator AtSMAX1 in response to nanomolar SL concentration. ShHTL7 mutagenesis analyses identified surface residues that contribute to its high-affinity binding to AtMAX2 and residues in the ligand binding pocket that confer broad-spectrum response to SLs with various structures. Crucially, yeast-three hybrid experiments showed that AtMAX2 confers responsiveness of the ShHTL7-AtSMAX1 interaction to picomolar levels of SL in line with the previously reported physiological sensitivity. These findings highlight the key role of SL-induced MAX2-ShHTL7-SMAX1 complex formation in determining the sensitivity to SL. Moreover, these data suggest a strategy to screen for compounds that could promote suicidal seed germination at physiologically relevant levels.
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Affiliation(s)
- Yupei Wang
- MOE Key Laboratory of Bioinformatics, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Ruifeng Yao
- State Key Laboratory of Chemo/Biosensing and Chemometrics, Hunan Provincial Key Laboratory of Plant Functional Genomics and Developmental Regulation, College of Biology, Hunan University, Changsha 410082, China
| | - Xiaoxi Du
- MOE Key Laboratory of Bioinformatics, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Lvjun Guo
- MOE Key Laboratory of Bioinformatics, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Li Chen
- State Key Laboratory of Chemo/Biosensing and Chemometrics, Hunan Provincial Key Laboratory of Plant Functional Genomics and Developmental Regulation, College of Biology, Hunan University, Changsha 410082, China
| | - Daoxin Xie
- MOE Key Laboratory of Bioinformatics, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Steven M Smith
- Australian Research Council Centre of Excellence for Plant Success in Nature and Agriculture, School of Natural Sciences, University of Tasmania, Hobart, Tasmania 7001, Australia
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
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Nelson DC. The mechanism of host-induced germination in root parasitic plants. PLANT PHYSIOLOGY 2021; 185:1353-1373. [PMID: 33793958 PMCID: PMC8133615 DOI: 10.1093/plphys/kiab043] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 01/25/2021] [Indexed: 05/25/2023]
Abstract
Chemical signals known as strigolactones (SLs) were discovered more than 50 years ago as host-derived germination stimulants of parasitic plants in the Orobanchaceae. Strigolactone-responsive germination is an essential adaptation of obligate parasites in this family, which depend upon a host for survival. Several species of obligate parasites, including witchweeds (Striga, Alectra spp.) and broomrapes (Orobanche, Phelipanche spp.), are highly destructive agricultural weeds that pose a significant threat to global food security. Understanding how parasites sense SLs and other host-derived stimulants will catalyze the development of innovative chemical and biological control methods. This review synthesizes the recent discoveries of strigolactone receptors in parasitic Orobanchaceae, their signaling mechanism, and key steps in their evolution.
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Affiliation(s)
- David C Nelson
- Department of Botany and Plant Sciences, University of California, Riverside, CA 92521 USA
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Brun G, Spallek T, Simier P, Delavault P. Molecular actors of seed germination and haustoriogenesis in parasitic weeds. PLANT PHYSIOLOGY 2021; 185:1270-1281. [PMID: 33793893 PMCID: PMC8133557 DOI: 10.1093/plphys/kiaa041] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 09/02/2020] [Indexed: 05/06/2023]
Abstract
One-sentence summary Recent advances provide insight into the molecular mechanisms underlying host-dependent seed germination and haustorium formation in parasitic plants.
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Affiliation(s)
- Guillaume Brun
- Department for Systematic Botany and Biodiversity, Institute for Biology, Humboldt-Universität zu Berlin, Philippstr. 13, D-10115 Berlin, Germany
| | - Thomas Spallek
- Department of Plant Physiology and Biochemistry, University of Hohenheim, D-70599 Stuttgart, Germany
| | - Philippe Simier
- Laboratory of Plant Biology and Pathology, University of Nantes, F-44322 Nantes Cedex 3, France
| | - Philippe Delavault
- Laboratory of Plant Biology and Pathology, University of Nantes, F-44322 Nantes Cedex 3, France
- Author for communication:
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Bouwmeester H, Li C, Thiombiano B, Rahimi M, Dong L. Adaptation of the parasitic plant lifecycle: germination is controlled by essential host signaling molecules. PLANT PHYSIOLOGY 2021; 185:1292-1308. [PMID: 33793901 PMCID: PMC8133609 DOI: 10.1093/plphys/kiaa066] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 11/12/2020] [Indexed: 05/25/2023]
Abstract
Parasitic plants are plants that connect with a haustorium to the vasculature of another, host, plant from which they absorb water, assimilates, and nutrients. Because of this parasitic lifestyle, parasitic plants need to coordinate their lifecycle with that of their host. Parasitic plants have evolved a number of host detection/host response mechanisms of which the germination in response to chemical host signals in one of the major families of parasitic plants, the Orobanchaceae, is a striking example. In this update review, we discuss these germination stimulants. We review the different compound classes that function as germination stimulants, how they are produced, and in which host plants. We discuss why they are reliable signals, how parasitic plants have evolved mechanisms that detect and respond to them, and whether they play a role in host specificity. The advances in the knowledge underlying this signaling relationship between host and parasitic plant have greatly improved our understanding of the evolution of plant parasitism and are facilitating the development of more effective control measures in cases where these parasitic plants have developed into weeds.
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Affiliation(s)
- Harro Bouwmeester
- Plant Hormone Biology group, Green Life Sciences cluster, Swammerdam Institute for Life Science, University of Amsterdam, 1098 XH Amsterdam, The Netherlands
| | - Changsheng Li
- Plant Hormone Biology group, Green Life Sciences cluster, Swammerdam Institute for Life Science, University of Amsterdam, 1098 XH Amsterdam, The Netherlands
| | - Benjamin Thiombiano
- Plant Hormone Biology group, Green Life Sciences cluster, Swammerdam Institute for Life Science, University of Amsterdam, 1098 XH Amsterdam, The Netherlands
| | - Mehran Rahimi
- Plant Hormone Biology group, Green Life Sciences cluster, Swammerdam Institute for Life Science, University of Amsterdam, 1098 XH Amsterdam, The Netherlands
| | - Lemeng Dong
- Plant Hormone Biology group, Green Life Sciences cluster, Swammerdam Institute for Life Science, University of Amsterdam, 1098 XH Amsterdam, The Netherlands
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Aquino B, Bradley JM, Lumba S. On the outside looking in: roles of endogenous and exogenous strigolactones. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 105:322-334. [PMID: 33215770 DOI: 10.1111/tpj.15087] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 09/27/2020] [Accepted: 10/21/2020] [Indexed: 05/15/2023]
Abstract
A collection of small molecules called strigolactones (SLs) act as both endogenous hormones to control plant development and as ecological communication cues between organisms. SL signalling overlaps with that of a class of smoke-derived compounds, karrikins (KARs), which have distinct yet overlapping developmental effects on plants. Although the roles of SLs in shoot and root development, in the promotion of arbuscular mycorrhizal (AM) fungal branching and in parasitic plant germination have been well characterized, recent data have illustrated broader roles for these compounds in the rhizosphere. Here, we review the known roles of SLs in development, growth of AM fungi and germination of parasitic plants to develop a framework for understanding the use of SLs as molecules of communication in the rhizosphere. It appears, for example, that there are many connections between SLs and phosphate utilization. Low phosphate levels regulate SL metabolism and, in turn, SLs sculpt root and shoot architecture to coordinate growth and optimize phosphate uptake from the environment. Plant-exuded SLs attract fungal symbionts to deliver inorganic phosphate (Pi) to the host. These and other examples suggest the boundary between exogenous and endogenous SL functions can be easily blurred and a more holistic view of these small molecules is likely to be required to fully understand SL biology. Related to this, we summarize and discuss evidence for a primitive role of SLs in moss as a quorum sensing-like molecule, providing a unifying concept of SLs as endogenous and exogenous signalling molecules.
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Affiliation(s)
- Bruno Aquino
- Department of Cell and Systems Biology, University of Toronto, 25 Willcocks Street, Toronto, M5S 3B2, Canada
| | - James M Bradley
- Department of Cell and Systems Biology, University of Toronto, 25 Willcocks Street, Toronto, M5S 3B2, Canada
| | - Shelley Lumba
- Department of Cell and Systems Biology, University of Toronto, 25 Willcocks Street, Toronto, M5S 3B2, Canada
- Centre for the Analysis of Genome Evolution and Function, University of Toronto, 25 Willcocks Street, Toronto, ON, M5S 3B2, Canada
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Fernández-Aparicio M, Delavault P, Timko MP. Management of Infection by Parasitic Weeds: A Review. PLANTS (BASEL, SWITZERLAND) 2020; 9:E1184. [PMID: 32932904 PMCID: PMC7570238 DOI: 10.3390/plants9091184] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 09/03/2020] [Accepted: 09/09/2020] [Indexed: 12/30/2022]
Abstract
Parasitic plants rely on neighboring host plants to complete their life cycle, forming vascular connections through which they withdraw needed nutritive resources. In natural ecosystems, parasitic plants form one component of the plant community and parasitism contributes to overall community balance. In contrast, when parasitic plants become established in low biodiversified agroecosystems, their persistence causes tremendous yield losses rendering agricultural lands uncultivable. The control of parasitic weeds is challenging because there are few sources of crop resistance and it is difficult to apply controlling methods selective enough to kill the weeds without damaging the crop to which they are physically and biochemically attached. The management of parasitic weeds is also hindered by their high fecundity, dispersal efficiency, persistent seedbank, and rapid responses to changes in agricultural practices, which allow them to adapt to new hosts and manifest increased aggressiveness against new resistant cultivars. New understanding of the physiological and molecular mechanisms behind the processes of germination and haustorium development, and behind the crop resistant response, in addition to the discovery of new targets for herbicides and bioherbicides will guide researchers on the design of modern agricultural strategies for more effective, durable, and health compatible parasitic weed control.
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Affiliation(s)
- Mónica Fernández-Aparicio
- Institute for Sustainable Agriculture, Consejo Superior de Investigaciones Científicas (CSIC), 14004 Córdoba, Spain
| | - Philippe Delavault
- Laboratory of Plant Biology and Pathology, University of Nantes, 44035 Nantes, France;
| | - Michael P. Timko
- Department of Biology University of Virginia, Charlottesville, VA 22904-4328, USA;
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Adewale SA, Badu-Apraku B, Akinwale RO, Paterne AA, Gedil M, Garcia-Oliveira AL. Genome-wide association study of Striga resistance in early maturing white tropical maize inbred lines. BMC PLANT BIOLOGY 2020; 20:203. [PMID: 32393176 PMCID: PMC7212567 DOI: 10.1186/s12870-020-02360-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 03/24/2020] [Indexed: 05/04/2023]
Abstract
BACKGROUND Striga hermonthica (Benth.) parasitism militates against increased maize production and productivity in savannas of sub-Saharan Africa (SSA). Identification of Striga resistance genes is important in developing genotypes with durable resistance. So far, there is only one report on the existence of QTL for Striga resistance on chromosome 6 of maize. The objective of this study was to identify genomic regions significantly associated with grain yield and other agronomic traits under artificial Striga field infestation. A panel of 132 early-maturing maize inbreds were phenotyped for key agronomic traits under Striga-infested and Striga-free conditions. The inbred lines were also genotyped using 47,440 DArTseq markers from which 7224 markers were retained for population structure analysis and genome-wide association study (GWAS). RESULTS The inbred lines were grouped into two major clusters based on structure analysis as well as the neighbor-joining hierarchical clustering. A total of 24 SNPs significantly associated with grain yield, Striga damage at 8 and 10 weeks after planting (WAP), ears per plant and ear aspect under Striga infestation were detected. Under Striga-free conditions, 11 SNPs significantly associated with grain yield, number of ears per plant and ear aspect were identified. Three markers physically located close to the putative genes GRMZM2G164743 (bin 10.05), GRMZM2G060216 (bin 3.06) and GRMZM2G103085 (bin 5.07) were detected, linked to grain yield, Striga damage at 8 and 10 WAP and number of ears per plant under Striga infestation, explaining 9 to 42% of the phenotypic variance. Furthermore, the S9_154,978,426 locus on chromosome 9 was found at 2.61 Mb close to the ZmCCD1 gene known to be associated with the reduction of strigolactone production in the maize roots. CONCLUSIONS Presented in this study is the first report of the identification of significant loci on chromosomes 9 and 10 of maize that are closely linked to ZmCCD1 and amt5 genes, respectively and may be related to plant defense mechanisms against Striga parasitism. After validation, the identified loci could be targets for breeders for marker-assisted selection (MAS) to accelerate genetic enhancement of maize for Striga resistance in the tropics, particularly in SSA, where the parasitic weed is endemic.
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Affiliation(s)
- Samuel Adeyemi Adewale
- International Institute of Tropical Agriculture (IITA), PMB 5320, Oyo Road, Ibadan, Nigeria
- Department of Crop Production and Protection, Obafemi Awolowo University, Ile-Ife, Nigeria
| | - Baffour Badu-Apraku
- International Institute of Tropical Agriculture (IITA), PMB 5320, Oyo Road, Ibadan, Nigeria
| | | | - Agre Angelot Paterne
- International Institute of Tropical Agriculture (IITA), PMB 5320, Oyo Road, Ibadan, Nigeria
| | - Melaku Gedil
- International Institute of Tropical Agriculture (IITA), PMB 5320, Oyo Road, Ibadan, Nigeria
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Emran S, Nawade B, Yahyaa M, Abu Nassar J, Tholl D, Eizenberg H, Ibdah M. Broomrape infestation in carrot (Daucus carota): Changes in carotenoid gene expression and carotenoid accumulation in the parasitic weed Phelipanche aegyptiaca and its host. Sci Rep 2020; 10:324. [PMID: 31942014 PMCID: PMC6962276 DOI: 10.1038/s41598-019-57298-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Accepted: 12/26/2019] [Indexed: 12/13/2022] Open
Abstract
Carotenogenesis has been intensively studied in carrot roots, and transcriptional regulation is thought to be the major factor in carotenoid accumulation in these organs. However, little is known about the transcriptional regulation of carotenoid biosynthetic genes concerning carotenoid accumulation during infestation by the obligate parasite Phelipanche aegyptiaca. HPLC analysis revealed a decrease in carotenoid levels of the different carrot cultivars when parasitized by P. aegyptiaca. Besides, we isolated and analyzed P. aegyptiaca tubercles parasitizing the various carrot root cultivars and show that they accumulate different carotenoids compared to those in non-infested carrot roots. Expression analysis of PHYTOENE SYNTHASE (PSY1) and CAROTENOID ISOMERASE (CRTISO) as well as the strigolactone apocarotenoid biosynthetic genes DWARF27 (D27), CAROTENOID CLEAVAGE DIOXYGENASE 7 (CCD7) and CCD8 revealed that their transcript levels showed significant variation in P. aegyptiaca infested carrot roots. After parasite infestation, the expression of these genes was strongly reduced, as were the carotenoid levels and this was more pronounced in the uncommon non-orange varieties. We also analyzed the parasite genes encoding D27, CCD7 and CCD8 and show that they are expressed in tubercles. This raises important questions of whether the parasite produces its carotenoids and apocarotenoids including strigolactones and whether the latter might have a role in tubercle development.
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Affiliation(s)
- Sewar Emran
- Newe Ya'ar Research Center, Agricultural Research Organization (ARO), Ramat Yishay, Israel
| | - Bhagwat Nawade
- Newe Ya'ar Research Center, Agricultural Research Organization (ARO), Ramat Yishay, Israel
| | - Mosaab Yahyaa
- Newe Ya'ar Research Center, Agricultural Research Organization (ARO), Ramat Yishay, Israel
| | - Jackline Abu Nassar
- Newe Ya'ar Research Center, Agricultural Research Organization (ARO), Ramat Yishay, Israel
| | - Dorothea Tholl
- Department of Biological Sciences, Virginia Polytechnic Institute and State University, 409 Latham Hall, 220 Ag Quad Lane, Blacksburg, Virginia, 24061, United States
| | - Hanan Eizenberg
- Newe Ya'ar Research Center, Agricultural Research Organization (ARO), Ramat Yishay, Israel
| | - Mwafaq Ibdah
- Newe Ya'ar Research Center, Agricultural Research Organization (ARO), Ramat Yishay, Israel.
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Brun G, Thoiron S, Braem L, Pouvreau JB, Montiel G, Lechat MM, Simier P, Gevaert K, Goormachtig S, Delavault P. CYP707As are effectors of karrikin and strigolactone signalling pathways in Arabidopsis thaliana and parasitic plants. PLANT, CELL & ENVIRONMENT 2019; 42:2612-2626. [PMID: 31134630 DOI: 10.1111/pce.13594] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Revised: 05/17/2019] [Accepted: 05/19/2019] [Indexed: 05/10/2023]
Abstract
Karrikins stimulate Arabidopsis thaliana germination, whereas parasitic weeds of the Orobanchaceae family have evolved to respond to host-exuded compounds such as strigolactones, dehydrocostus lactone, and 2-phenylethyl isothiocyanate. In Phelipanche ramosa, strigolactone-induced germination was shown to require one of the CYP707A proteins involved in abscisic acid catabolism. Here, germination and gene expression were analysed to investigate the role of CYP707As in germination of both parasitic plants and Arabidopsis upon perception of germination stimulants, after using pharmacological inhibitors and Arabidopsis mutants disrupting germination signals. CYP707A genes were up-regulated upon treatment with effective germination stimulants in both parasitic plants and Arabidopsis. Obligate parasitic plants exhibited both intensified up-regulation of CYP707A genes and increased sensitivity to the CYP707A inhibitor abscinazole-E2B, whereas Arabidopsis cyp707a mutants still positively responded to germination stimulation. In Arabidopsis, CYP707A regulation required the canonical karrikin signalling pathway KAI2/MAX2/SMAX1 and the transcription factor WRKY33. Finally, CYP707As and WRKY33 also modulated Arabidopsis root architecture in response to the synthetic strigolactone rac-GR24, and wrky33-1 exhibited a shoot hyperbranched phenotype. This study suggests that the lack of host-independent germination in obligate parasites is associated with an exacerbated CYP707A induction and that CYP707As and WRKY33 are new players involved in a variety of strigolactone/karrikin responses.
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Affiliation(s)
- Guillaume Brun
- Université de Nantes, Laboratoire de Biologie et Pathologie Végétales LBPV, EA1157 F-44000, Nantes, France
| | - Séverine Thoiron
- Université de Nantes, Laboratoire de Biologie et Pathologie Végétales LBPV, EA1157 F-44000, Nantes, France
| | - Lukas Braem
- VIB Center for Plant Systems Biology, Technologiepark 71, 9052, Zwijnaarde, Belgium
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark, 71, 9052, Zwijnaarde, Belgium
- VIB Center for Medical Biotechnology, Albert Baertsoenkaai, 3, 9000, Ghent, Belgium
- Department of Biochemistry, Ghent University, Albert Baertsoenkaai 3, 9000, Ghent, Belgium
| | - Jean-Bernard Pouvreau
- Université de Nantes, Laboratoire de Biologie et Pathologie Végétales LBPV, EA1157 F-44000, Nantes, France
| | - Grégory Montiel
- Université de Nantes, Laboratoire de Biologie et Pathologie Végétales LBPV, EA1157 F-44000, Nantes, France
| | - Marc-Marie Lechat
- Université de Nantes, Laboratoire de Biologie et Pathologie Végétales LBPV, EA1157 F-44000, Nantes, France
| | - Philippe Simier
- Université de Nantes, Laboratoire de Biologie et Pathologie Végétales LBPV, EA1157 F-44000, Nantes, France
| | - Kris Gevaert
- VIB Center for Medical Biotechnology, Albert Baertsoenkaai, 3, 9000, Ghent, Belgium
- Department of Biochemistry, Ghent University, Albert Baertsoenkaai 3, 9000, Ghent, Belgium
| | - Sofie Goormachtig
- VIB Center for Plant Systems Biology, Technologiepark 71, 9052, Zwijnaarde, Belgium
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark, 71, 9052, Zwijnaarde, Belgium
| | - Philippe Delavault
- Université de Nantes, Laboratoire de Biologie et Pathologie Végétales LBPV, EA1157 F-44000, Nantes, France
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14
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Structural analysis of HTL and D14 proteins reveals the basis for ligand selectivity in Striga. Nat Commun 2018; 9:3947. [PMID: 30258184 PMCID: PMC6158167 DOI: 10.1038/s41467-018-06452-2] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 08/29/2018] [Indexed: 12/20/2022] Open
Abstract
HYPOSENSITIVE TO LIGHT (HTL) and DWARF14 (D14) mediate the perception of karrikin and strigolactone, which stimulates germination of the parasitic weed Striga. However, their role in parasitic seeds is poorly understood, and the basis for their differing responsiveness remains unclear. Here, we show that Striga hermonthica HTL proteins (ShHTLs) in ‘conserved’ and ‘intermediate’ clades are able to bind karrikin. The ‘divergent’ clade is able to hydrolyze strigolactone. Unexpectedly, we find that ShD14 is also capable of hydrolyzing strigolactone. Through comparative analysis of ShHTLs and ShD14 crystal structures, we provide insights into the basis for their selectivity. Moreover, we show that both ShD14 and divergent clade ShHTLs, but not conserved and intermediate clade ShHTLs, can interact with the putative downstream signaling component ShMAX2 in the presence of the synthetic strigolactone, rac-GR24. These findings provide insight into how strigolactone is perceived and how ligand specificity is determined. HTL and D14 receptors perceive the structurally similar signaling compounds karrikin and strigolactone. Here, the authors show that ShD14 and a divergent clade of ShHTLs from Strigae capable of recognizing strigolact are capable of recognizing strigolactone and provide structural insights into the evolution of ligand specificity.
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15
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Jiang K, Asami T. Chemical regulators of plant hormones and their applications in basic research and agriculture*. Biosci Biotechnol Biochem 2018; 82:1265-1300. [DOI: 10.1080/09168451.2018.1462693] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
ABSTRACT
Plant hormones are small molecules that play versatile roles in regulating plant growth, development, and responses to the environment. Classic methodologies, including genetics, analytic chemistry, biochemistry, and molecular biology, have contributed to the progress in plant hormone studies. In addition, chemical regulators of plant hormone functions have been important in such studies. Today, synthetic chemicals, including plant growth regulators, are used to study and manipulate biological systems, collectively referred to as chemical biology. Here, we summarize the available chemical regulators and their contributions to plant hormone studies. We also pose questions that remain to be addressed in plant hormone studies and that might be solved with the help of chemical regulators.
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Affiliation(s)
- Kai Jiang
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Tadao Asami
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
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16
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Cheng T, Wang D, Wang Y, Zhang S, Zhang C, Liu S, Xi Y, Sun F. Identification and functional characterization of a MAX2 ortholog from switchgrass (Panicum virgatum L.). PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2018; 128:106-114. [PMID: 29775862 DOI: 10.1016/j.plaphy.2018.05.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 05/09/2018] [Accepted: 05/09/2018] [Indexed: 06/08/2023]
Abstract
Switchgrass (Panicum virgatum L.) is a sustainable cellulosic energy crop with high biomass yield on marginal soils. Tillering, an important agronomic characteristic related to biomass production in gramineous plants, is regulated by complex interacting factors, such as plant hormones. Strigolactones (SLs) comprise a novel class of plant hormones that inhibit shoot branching. The MORE AXILLARY GROWTH2 (MAX2)/DWARF 3 (D3)/RAMOSUS (RMS4) genes encode proteins involved in the SL signaling pathway in various plants. The switchgrass tetraploid genome likely contains two high-similarity MAX2 homologs, one of which is 6 bp longer than the other. The longest is named PvMAX2 and is the ortholog of MAX2 in Arabidopsis, D3 in rice, and RMS4 in petunia. PvMAX2 is expressed ubiquitously in switchgrass tissues, with higher expression levels observed in the stem and shoot. PvMAX2 gene expression is upregulated by GR24, a synthetic SL analog. Ectopic expression of PvMAX2 in the Arabidopsis max2 mutant rescued the dwarf and bushy phenotypes and small leaf size in the mutant, suggesting that functions of AtMAX2 in Arabidopsis are conserved in PvMAX2. Ectopic PvMAX2 expression also restored the wild-type primary root and hypocotyl length phenotypes and restored the response to GR24. These results indicate that PvMAX2 may play an important role in switchgrass tillering through the SL pathway.
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Affiliation(s)
- Tingting Cheng
- College of Agronomy, Northwest A&F University, Yangling, Shaanxi 712100, China; State Key Laboratory of Crop Stress Biology for Arid Areas, Yangling, Shaanxi 712100, China
| | - Donghua Wang
- College of Agronomy, Northwest A&F University, Yangling, Shaanxi 712100, China; State Key Laboratory of Crop Stress Biology for Arid Areas, Yangling, Shaanxi 712100, China
| | - Yongfeng Wang
- College of Agronomy, Northwest A&F University, Yangling, Shaanxi 712100, China; State Key Laboratory of Crop Stress Biology for Arid Areas, Yangling, Shaanxi 712100, China
| | - Shumeng Zhang
- College of Agronomy, Northwest A&F University, Yangling, Shaanxi 712100, China; State Key Laboratory of Crop Stress Biology for Arid Areas, Yangling, Shaanxi 712100, China
| | - Chao Zhang
- College of Agronomy, Northwest A&F University, Yangling, Shaanxi 712100, China; State Key Laboratory of Crop Stress Biology for Arid Areas, Yangling, Shaanxi 712100, China
| | - Shudong Liu
- College of Agronomy, Northwest A&F University, Yangling, Shaanxi 712100, China; State Key Laboratory of Crop Stress Biology for Arid Areas, Yangling, Shaanxi 712100, China
| | - Yajun Xi
- College of Agronomy, Northwest A&F University, Yangling, Shaanxi 712100, China; State Key Laboratory of Crop Stress Biology for Arid Areas, Yangling, Shaanxi 712100, China
| | - Fengli Sun
- College of Agronomy, Northwest A&F University, Yangling, Shaanxi 712100, China; State Key Laboratory of Crop Stress Biology for Arid Areas, Yangling, Shaanxi 712100, China.
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17
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Brun G, Braem L, Thoiron S, Gevaert K, Goormachtig S, Delavault P. Seed germination in parasitic plants: what insights can we expect from strigolactone research? JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:2265-2280. [PMID: 29281042 DOI: 10.1093/jxb/erx472] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 12/14/2017] [Indexed: 06/07/2023]
Abstract
Obligate root-parasitic plants belonging to the Orobanchaceae family are deadly pests for major crops all over the world. Because these heterotrophic plants severely damage their hosts even before emerging from the soil, there is an unequivocal need to design early and efficient methods for their control. The germination process of these species has probably undergone numerous selective pressure events in the course of evolution, in that the perception of host-derived molecules is a necessary condition for seeds to germinate. Although most of these molecules belong to the strigolactones, structurally different molecules have been identified. Since strigolactones are also classified as novel plant hormones that regulate several physiological processes other than germination, the use of autotrophic model plant species has allowed the identification of many actors involved in the strigolactone biosynthesis, perception, and signal transduction pathways. Nevertheless, many questions remain to be answered regarding the germination process of parasitic plants. For instance, how did parasitic plants evolve to germinate in response to a wide variety of molecules, while autotrophic plants do not? What particular features are associated with their lack of spontaneous germination? In this review, we attempt to illustrate to what extent conclusions from research into strigolactones could be applied to better understand the biology of parasitic plants.
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Affiliation(s)
- Guillaume Brun
- Laboratoire de Biologie et Pathologie Végétales, EA, Université de Nantes, BP Nantes Cedex, France
| | - Lukas Braem
- VIB-UGent Center for Plant Systems Biology, Technologiepark Zwijnaarde, Belgium
- VIB-UGent Center for Medical Biotechnology, Albert Baertsoenkaai Ghent, Belgium
| | - Séverine Thoiron
- Laboratoire de Biologie et Pathologie Végétales, EA, Université de Nantes, BP Nantes Cedex, France
| | - Kris Gevaert
- VIB-UGent Center for Medical Biotechnology, Albert Baertsoenkaai Ghent, Belgium
- Department of Biochemistry, Ghent University, Albert Baertsoenkaai Ghent, Belgium
| | - Sofie Goormachtig
- VIB-UGent Center for Plant Systems Biology, Technologiepark Zwijnaarde, Belgium
| | - Philippe Delavault
- Laboratoire de Biologie et Pathologie Végétales, EA, Université de Nantes, BP Nantes Cedex, France
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18
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Tsuchiya Y, Yoshimura M, Hagihara S. The dynamics of strigolactone perception in Striga hermonthica: a working hypothesis. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:2281-2290. [PMID: 29474634 DOI: 10.1093/jxb/ery061] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 02/14/2018] [Indexed: 06/08/2023]
Abstract
Plant-derived strigolactones have diverse functions at ecological scale, including effects upon the growth of plants themselves. The parasitic plants from the family Orobanchaceae interfere with the ecological and hormonal functions of strigolactones to generate unique germination abilities based on the sensing of host-derived strigolactones. Although the recent discovery of strigolactone receptors has enabled us to begin elucidating the mechanism of strigolactone perception, how perception relates to plant parasitism is still a mystery. In this review, we explore emerging questions by introducing recent advances in strigolactone research in parasitic plants. We also attempt to construct a conceptual framework for the unique in planta dynamics of strigolactone perception uncovered through the use of fluorescent probes for strigolactone receptors. Understanding the mechanisms of strigolactone-related processes is essential for controlling the parasitic plant Striga hermonthica, which has caused devastating damage to crop production in Africa.
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Affiliation(s)
- Yuichiro Tsuchiya
- Institute of Transformative Bio-Molecules, Nagoya University, Chikusa, Nagoya, Japan
| | - Masahiko Yoshimura
- Department of Chemistry, Graduate School of Science, Nagoya University, Chikusa, Nagoya, Japan
| | - Shinya Hagihara
- Department of Chemistry, Graduate School of Science, Nagoya University, Chikusa, Nagoya, Japan
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19
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Wang Y, Bouwmeester HJ. Structural diversity in the strigolactones. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:2219-2230. [PMID: 29522118 DOI: 10.1093/jxb/ery091] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2017] [Accepted: 03/05/2018] [Indexed: 05/25/2023]
Abstract
Strigolactones (SLs) are a class of signalling molecules secreted by the roots of plants into the rhizosphere. On the one hand, they serve as the signal for recruiting arbuscular mycorrhizal fungi which have a symbiotic relationship with plants. On the other hand, they are also host detection signals for the non-symbiotic, pathogenic, root parasitic plants, which use the SLs as germination stimulants. Finally, recently the SLs were discovered to be a new class of plant hormones that regulate processes such as branching/tillering and root architecture. Intriguingly, >25 different SLs have already been discovered that all have the so-called D-ring but otherwise display many differences in structure and functional groups. In this review, we will critically discuss the structural diversity in the SLs. How are they synthesized in plants; how has this structural diversity possibly evolved; what is the biological relevance of this diversity; and what does this imply for the perception of the SLs by receptors in the plant itself and in other organisms? Finally, we conclude that only little is known about the biological significance of this structural diversity, and we will give an outlook on how to elucidate their importance further.
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Affiliation(s)
- Yanting Wang
- Plant hormone biology, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park, XH Amsterdam, The Netherlands
| | - Harro J Bouwmeester
- Plant hormone biology, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park, XH Amsterdam, The Netherlands
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20
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Hamiaux C, Drummond RSM, Luo Z, Lee HW, Sharma P, Janssen BJ, Perry NB, Denny WA, Snowden KC. Inhibition of strigolactone receptors by N-phenylanthranilic acid derivatives: Structural and functional insights. J Biol Chem 2018. [PMID: 29523686 DOI: 10.1074/jbc.ra117.001154] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The strigolactone (SL) family of plant hormones regulates a broad range of physiological processes affecting plant growth and development and also plays essential roles in controlling interactions with parasitic weeds and symbiotic fungi. Recent progress elucidating details of SL biosynthesis, signaling, and transport offers many opportunities for discovering new plant-growth regulators via chemical interference. Here, using high-throughput screening and downstream biochemical assays, we identified N-phenylanthranilic acid derivatives as potent inhibitors of the SL receptors from petunia (DAD2), rice (OsD14), and Arabidopsis (AtD14). Crystal structures of DAD2 and OsD14 in complex with inhibitors further provided detailed insights into the inhibition mechanism, and in silico modeling of 19 other plant strigolactone receptors suggested that these compounds are active across a large range of plant species. Altogether, these results provide chemical tools for investigating SL signaling and further define a framework for structure-based approaches to design and validate optimized inhibitors of SL receptors for specific plant targets.
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Affiliation(s)
- Cyril Hamiaux
- From the New Zealand Institute for Plant and Food Research Limited, Private Bag 92169, Auckland 1142, New Zealand,
| | - Revel S M Drummond
- From the New Zealand Institute for Plant and Food Research Limited, Private Bag 92169, Auckland 1142, New Zealand
| | - Zhiwei Luo
- From the New Zealand Institute for Plant and Food Research Limited, Private Bag 92169, Auckland 1142, New Zealand
| | - Hui Wen Lee
- From the New Zealand Institute for Plant and Food Research Limited, Private Bag 92169, Auckland 1142, New Zealand.,the School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Prachi Sharma
- From the New Zealand Institute for Plant and Food Research Limited, Private Bag 92169, Auckland 1142, New Zealand.,the School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Bart J Janssen
- From the New Zealand Institute for Plant and Food Research Limited, Private Bag 92169, Auckland 1142, New Zealand
| | - Nigel B Perry
- the Department of Chemistry, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand.,the New Zealand Institute for Plant and Food Research Limited, Department of Chemistry, University of Otago, P.O. Box 56, Dunedin, New Zealand, and
| | - William A Denny
- the Auckland Cancer Society Research Centre, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Kimberley C Snowden
- From the New Zealand Institute for Plant and Food Research Limited, Private Bag 92169, Auckland 1142, New Zealand,
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21
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De Cuyper C, Struk S, Braem L, Gevaert K, De Jaeger G, Goormachtig S. Strigolactones, karrikins and beyond. PLANT, CELL & ENVIRONMENT 2017; 40:1691-1703. [PMID: 28558130 DOI: 10.1111/pce.12996] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2016] [Revised: 05/24/2017] [Accepted: 05/24/2017] [Indexed: 05/12/2023]
Abstract
The plant hormones strigolactones are synthesized from carotenoids and signal via the α/β hydrolase DWARF 14 (D14) and the F-box protein MORE AXILLARY GROWTH 2 (MAX2). Karrikins, molecules produced upon fire, share MAX2 for signalling, but depend on the D14 paralog KARRIKIN INSENSITIVE 2 (KAI2) for perception with strong evidence that the MAX2-KAI2 protein complex might also recognize so far unknown plant-made karrikin-like molecules. Thus, the phenotypes of the max2 mutants are the complex consequence of a loss of both D14-dependent and KAI2-dependent signalling, hence, the reason why some biological roles, attributed to strigolactones based on max2 phenotypes, could never be observed in d14 or in the strigolactone-deficient max3 and max4 mutants. Moreover, the broadly used synthetic strigolactone analog rac-GR24 has been shown to mimic strigolactone as well as karrikin(-like) signals, providing an extra level of complexity in the distinction of the unique and common roles of both molecules in plant biology. Here, a critical overview is provided of the diverse biological processes regulated by strigolactones and/or karrikins. These two growth regulators are considered beyond their boundaries, and the importance of the yet unknown karrikin-like molecules is discussed as well.
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Affiliation(s)
- Carolien De Cuyper
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052, Ghent, Belgium
- Center for Plant Systems Biology, VIB, 9052, Ghent, Belgium
| | - Sylwia Struk
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052, Ghent, Belgium
- Center for Plant Systems Biology, VIB, 9052, Ghent, Belgium
| | - Lukas Braem
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052, Ghent, Belgium
- Center for Plant Systems Biology, VIB, 9052, Ghent, Belgium
- Department of Biochemistry, Ghent University, 9000, Ghent, Belgium
- Medical Biotechnology Center, VIB, 9000, Ghent, Belgium
| | - Kris Gevaert
- Department of Biochemistry, Ghent University, 9000, Ghent, Belgium
- Medical Biotechnology Center, VIB, 9000, Ghent, Belgium
| | - Geert De Jaeger
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052, Ghent, Belgium
- Center for Plant Systems Biology, VIB, 9052, Ghent, Belgium
| | - Sofie Goormachtig
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052, Ghent, Belgium
- Center for Plant Systems Biology, VIB, 9052, Ghent, Belgium
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22
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Lumba S, Subha A, McCourt P. Found in Translation: Applying Lessons from Model Systems to Strigolactone Signaling in Parasitic Plants. Trends Biochem Sci 2017; 42:556-565. [PMID: 28495334 DOI: 10.1016/j.tibs.2017.04.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Revised: 04/05/2017] [Accepted: 04/20/2017] [Indexed: 01/14/2023]
Abstract
Strigolactones (SLs) are small molecules that act as endogenous hormones to regulate plant development as well as exogenous cues that help parasitic plants to infect their hosts. Given that parasitic plants are experimentally challenging systems, researchers are using two approaches to understand how they respond to host-derived SLs. The first involves extrapolating information on SLs from model genetic systems to dissect their roles in parasitic plants. The second uses chemicals to probe SL signaling directly in the parasite Striga hermonthica. These approaches indicate that parasitic plants have co-opted a family of α/β hydrolases to perceive SLs. The importance of this genetic and chemical information cannot be overstated since parasitic plant infestations are major obstacles to food security in the developing world.
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Affiliation(s)
- Shelley Lumba
- Cell and Systems Biology, University of Toronto and the Centre for the Analysis of Genome Evolution and Function, University of Toronto, Toronto, ON M5S 3B2, Canada
| | - Asrinus Subha
- Cell and Systems Biology, University of Toronto and the Centre for the Analysis of Genome Evolution and Function, University of Toronto, Toronto, ON M5S 3B2, Canada
| | - Peter McCourt
- Cell and Systems Biology, University of Toronto and the Centre for the Analysis of Genome Evolution and Function, University of Toronto, Toronto, ON M5S 3B2, Canada.
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23
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OaMAX2 of Orobanche aegyptiaca and Arabidopsis AtMAX2 share conserved functions in both development and drought responses. Biochem Biophys Res Commun 2016; 478:521-6. [PMID: 27425246 DOI: 10.1016/j.bbrc.2016.07.065] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Accepted: 07/13/2016] [Indexed: 11/20/2022]
Abstract
Previous studies in Arabidopsis reported that the MAX2 (more axillary growth 2) gene is a component of the strigolactone (SL) signaling pathway, which regulates a wide range of biological processes, from plant growth and development to environmental stress responses. Orobanche aegyptiaca is a harmful parasitic plant for many economically important crops. Seed germination of O. aegyptiaca is very sensitive to SLs, suggesting that O. aegyptiaca may contain components of the SL signaling pathway. To investigate this hypothesis, we identified and cloned a MAX2 ortholog from O. aegyptiaca for complementation analyses using the Arabidopsis Atmax2 mutant. The so-called OaMAX2 gene could rescue phenotypes of the Atmax2 mutant in various tested developmental aspects, including seed germination, shoot branching, leaf senescence and growth and development of hypocotyl, root hair, primary root and lateral root. More importantly, OaMAX2 could enhance the drought tolerance of Atmax2 mutant, suggesting its ability to restore the drought-tolerant phenotype of mutant plants defected in AtMAX2 function. Thus, this study provides genetic evidence that the functions of the MAX2 orthologs, and perhaps the MAX2 signaling pathways, are conserved in parasitic and non-parasitic plants. Furthermore, the results of our study enable us to develop a strategy to fight against parasitic plants by suppressing the MAX signaling, which ultimately leads to enhanced productivity of crop plants.
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Fernández-Aparicio M, Reboud X, Gibot-Leclerc S. Broomrape Weeds. Underground Mechanisms of Parasitism and Associated Strategies for their Control: A Review. FRONTIERS IN PLANT SCIENCE 2016; 7:135. [PMID: 26925071 PMCID: PMC4759268 DOI: 10.3389/fpls.2016.00135] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Accepted: 01/12/2016] [Indexed: 05/20/2023]
Abstract
Broomrapes are plant-parasitic weeds which constitute one of the most difficult-to-control of all biotic constraints that affect crops in Mediterranean, central and eastern Europe, and Asia. Due to their physical and metabolic overlap with the crop, their underground parasitism, their achlorophyllous nature, and hardly destructible seed bank, broomrape weeds are usually not controlled by management strategies designed for non-parasitic weeds. Instead, broomrapes are in current state of intensification and spread due to lack of broomrape-specific control programs, unconscious introduction to new areas and may be decline of herbicide use and global warming to a lesser degree. We reviewed relevant facts about the biology and physiology of broomrape weeds and the major feasible control strategies. The points of vulnerability of some underground events, key for their parasitism such as crop-induced germination or haustorial development are reviewed as inhibition targets of the broomrape-crop association. Among the reviewed strategies are those aimed (1) to reduce broomrape seed bank viability, such as fumigation, herbigation, solarization and use of broomrape-specific pathogens; (2) diversion strategies to reduce the broomrape ability to timely detect the host such as those based on promotion of suicidal germination, on introduction of allelochemical interference, or on down-regulating host exudation of germination-inducing factors; (3) strategies to inhibit the capacity of the broomrape seedling to penetrate the crop and connect with the vascular system, such as biotic or abiotic inhibition of broomrape radicle growth and crop resistance to broomrape penetration either natural, genetically engineered or elicited by biotic- or abiotic-resistance-inducing agents; and (4) strategies acting once broomrape seedling has bridged its vascular system with that of the host, aimed to impede or to endure the parasitic sink such as those based on the delivery of herbicides via haustoria, use of resistant or tolerant varieties and implementation of cultural practices improving crop competitiveness.
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Tsuchiya Y, Yoshimura M, Sato Y, Kuwata K, Toh S, Holbrook-Smith D, Zhang H, McCourt P, Itami K, Kinoshita T, Hagihara S. PARASITIC PLANTS. Probing strigolactone receptors in Striga hermonthica with fluorescence. Science 2015; 349:864-8. [PMID: 26293962 DOI: 10.1126/science.aab3831] [Citation(s) in RCA: 186] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Elucidating the signaling mechanism of strigolactones has been the key to controlling the devastating problem caused by the parasitic plant Striga hermonthica. To overcome the genetic intractability that has previously interfered with identification of the strigolactone receptor, we developed a fluorescence turn-on probe, Yoshimulactone Green (YLG), which activates strigolactone signaling and illuminates signal perception by the strigolactone receptors. Here we describe how strigolactones bind to and act via ShHTLs, the diverged family of α/β hydrolase-fold proteins in Striga. Live imaging using YLGs revealed that a dynamic wavelike propagation of strigolactone perception wakes up Striga seeds. We conclude that ShHTLs function as the strigolactone receptors mediating seed germination in Striga. Our findings enable access to strigolactone receptors and observation of the regulatory dynamics for strigolactone signal transduction in Striga.
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Affiliation(s)
- Yuichiro Tsuchiya
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan. Department of Cell and Systems Biology, University of Toronto, 25 Willcocks Street, Toronto, Ontario M5S 3B2, Canada.
| | - Masahiko Yoshimura
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan. Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
| | - Yoshikatsu Sato
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
| | - Keiko Kuwata
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
| | - Shigeo Toh
- Department of Cell and Systems Biology, University of Toronto, 25 Willcocks Street, Toronto, Ontario M5S 3B2, Canada
| | - Duncan Holbrook-Smith
- Department of Cell and Systems Biology, University of Toronto, 25 Willcocks Street, Toronto, Ontario M5S 3B2, Canada
| | - Hua Zhang
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
| | - Peter McCourt
- Department of Cell and Systems Biology, University of Toronto, 25 Willcocks Street, Toronto, Ontario M5S 3B2, Canada
| | - Kenichiro Itami
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan. Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan. Japan Science and Technology Agency-Exploratory Research for Advanced Technology, Itami Molecular Nanocarbon Project, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
| | - Toshinori Kinoshita
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan. Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
| | - Shinya Hagihara
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan. Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan.
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Conn CE, Bythell-Douglas R, Neumann D, Yoshida S, Whittington B, Westwood JH, Shirasu K, Bond CS, Dyer KA, Nelson DC. Convergent evolution of strigolactone perception enabled host detection in parasitic plants. Science 2015; 349:540-3. [DOI: 10.1126/science.aab1140] [Citation(s) in RCA: 219] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Mitsumasu K, Seto Y, Yoshida S. Apoplastic interactions between plants and plant root intruders. FRONTIERS IN PLANT SCIENCE 2015; 6:617. [PMID: 26322059 PMCID: PMC4536382 DOI: 10.3389/fpls.2015.00617] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Accepted: 07/27/2015] [Indexed: 05/06/2023]
Abstract
Numerous pathogenic or parasitic organisms attack plant roots to obtain nutrients, and the apoplast including the plant cell wall is where the plant cell meets such organisms. Root parasitic angiosperms and nematodes are two distinct types of plant root parasites but share some common features in their strategies for breaking into plant roots. Striga and Orobanche are obligate root parasitic angiosperms that cause devastating agricultural problems worldwide. Parasitic plants form an invasion organ called a haustorium, where plant cell wall degrading enzymes (PCWDEs) are highly expressed. Plant-parasitic nematodes are another type of agriculturally important plant root parasite. These nematodes breach the plant cell walls by protruding a sclerotized stylet from which PCWDEs are secreted. Responding to such parasitic invasion, host plants activate their own defense responses against parasites. Endoparasitic nematodes secrete apoplastic effectors to modulate host immune responses and to facilitate the formation of a feeding site. Apoplastic communication between hosts and parasitic plants also contributes to their interaction. Parasitic plant germination stimulants, strigolactones, are recently identified apoplastic signals that are transmitted over long distances from biosynthetic sites to functioning sites. Here, we discuss recent advances in understanding the importance of apoplastic signals and cell walls for plant-parasite interactions.
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Affiliation(s)
- Kanako Mitsumasu
- Graduate School of Science and Technology, Kumamoto University, Chuo-ku, Japan
| | - Yoshiya Seto
- Department of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, Aoba-ku, Japan
| | - Satoko Yoshida
- RIKEN Center for Sustainable Resource Science, Yokohama, Japan
- *Correspondence: Satoko Yoshida, RIKEN Center for Sustainable Resource Science, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan,
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Das M, Fernández-Aparicio M, Yang Z, Huang K, Wickett NJ, Alford S, Wafula EK, dePamphilis C, Bouwmeester H, Timko MP, Yoder JI, Westwood JH. Parasitic Plants <i>Striga</i> and <i>Phelipanche</i> Dependent upon Exogenous Strigolactones for Germination Have Retained Genes for Strigolactone Biosynthesis. ACTA ACUST UNITED AC 2015. [DOI: 10.4236/ajps.2015.68120] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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29
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Yang Z, Wafula EK, Honaas LA, Zhang H, Das M, Fernandez-Aparicio M, Huang K, Bandaranayake PCG, Wu B, Der JP, Clarke CR, Ralph PE, Landherr L, Altman NS, Timko MP, Yoder JI, Westwood JH, dePamphilis CW. Comparative transcriptome analyses reveal core parasitism genes and suggest gene duplication and repurposing as sources of structural novelty. Mol Biol Evol 2014; 32:767-90. [PMID: 25534030 PMCID: PMC4327159 DOI: 10.1093/molbev/msu343] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The origin of novel traits is recognized as an important process underlying many major evolutionary radiations. We studied the genetic basis for the evolution of haustoria, the novel feeding organs of parasitic flowering plants, using comparative transcriptome sequencing in three species of Orobanchaceae. Around 180 genes are upregulated during haustorial development following host attachment in at least two species, and these are enriched in proteases, cell wall modifying enzymes, and extracellular secretion proteins. Additionally, about 100 shared genes are upregulated in response to haustorium inducing factors prior to host attachment. Collectively, we refer to these newly identified genes as putative “parasitism genes.” Most of these parasitism genes are derived from gene duplications in a common ancestor of Orobanchaceae and Mimulus guttatus, a related nonparasitic plant. Additionally, the signature of relaxed purifying selection and/or adaptive evolution at specific sites was detected in many haustorial genes, and may play an important role in parasite evolution. Comparative analysis of gene expression patterns in parasitic and nonparasitic angiosperms suggests that parasitism genes are derived primarily from root and floral tissues, but with some genes co-opted from other tissues. Gene duplication, often taking place in a nonparasitic ancestor of Orobanchaceae, followed by regulatory neofunctionalization, was an important process in the origin of parasitic haustoria.
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Affiliation(s)
- Zhenzhen Yang
- Intercollege Graduate Program in Plant Biology, Huck Institutes of the Life Sciences, The Pennsylvania State University Department of Biology, The Pennsylvania State University Institute of Molecular Evolutionary Genetics, Huck Institutes of the Life Sciences, The Pennsylvania State University
| | - Eric K Wafula
- Department of Biology, The Pennsylvania State University Institute of Molecular Evolutionary Genetics, Huck Institutes of the Life Sciences, The Pennsylvania State University
| | - Loren A Honaas
- Intercollege Graduate Program in Plant Biology, Huck Institutes of the Life Sciences, The Pennsylvania State University Department of Biology, The Pennsylvania State University Institute of Molecular Evolutionary Genetics, Huck Institutes of the Life Sciences, The Pennsylvania State University
| | - Huiting Zhang
- Intercollege Graduate Program in Plant Biology, Huck Institutes of the Life Sciences, The Pennsylvania State University Department of Biology, The Pennsylvania State University
| | - Malay Das
- Department of Plant Pathology, Physiology and Weed Science, Virginia Polytechnic Institute and State University
| | - Monica Fernandez-Aparicio
- Department of Plant Pathology, Physiology and Weed Science, Virginia Polytechnic Institute and State University Department of Biology, University of Virginia
| | - Kan Huang
- Department of Biology, University of Virginia
| | | | - Biao Wu
- Department of Plant Sciences, University of California, Davis
| | - Joshua P Der
- Department of Biology, The Pennsylvania State University Institute of Molecular Evolutionary Genetics, Huck Institutes of the Life Sciences, The Pennsylvania State University
| | - Christopher R Clarke
- Department of Plant Pathology, Physiology and Weed Science, Virginia Polytechnic Institute and State University
| | - Paula E Ralph
- Department of Biology, The Pennsylvania State University
| | - Lena Landherr
- Department of Biology, The Pennsylvania State University
| | - Naomi S Altman
- Department of Statistics and Huck Institutes of the Life Sciences, The Pennsylvania State University
| | | | - John I Yoder
- Department of Plant Sciences, University of California, Davis
| | - James H Westwood
- Department of Plant Pathology, Physiology and Weed Science, Virginia Polytechnic Institute and State University
| | - Claude W dePamphilis
- Intercollege Graduate Program in Plant Biology, Huck Institutes of the Life Sciences, The Pennsylvania State University Department of Biology, The Pennsylvania State University Institute of Molecular Evolutionary Genetics, Huck Institutes of the Life Sciences, The Pennsylvania State University
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Koltai H. Receptors, repressors, PINs: a playground for strigolactone signaling. TRENDS IN PLANT SCIENCE 2014; 19:727-33. [PMID: 25037847 DOI: 10.1016/j.tplants.2014.06.008] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Revised: 06/13/2014] [Accepted: 06/20/2014] [Indexed: 05/20/2023]
Abstract
Strigolactones, previously identified as active stimuli of seed germination in parasitic plants, are now recognized as a new group of plant hormones that are active in both shoots and roots. Here, we review recent insights into the concepts of strigolactones-signal transduction and their mode of action. Although strigolactones are sensed via a cell-specific reception system, at least some aspects of their activity are conducted in a non-cell-autonomous fashion. Strigolactones also affect trafficking and plasma-membrane localization of the auxin transporter PIN, thereby regulating auxin flux. We present a model for strigolactone-signal transduction that might also explain the integration of strigolactones into other hormone-signaling pathways via the regulation of PIN auxin transporters.
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Affiliation(s)
- Hinanit Koltai
- Institute of Plant Sciences, ARO, Volcani Center, Bet-Dagan 50250, Israel.
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Koltai H. Implications of non-specific strigolactone signaling in the rhizosphere. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2014; 225:9-14. [PMID: 25017154 DOI: 10.1016/j.plantsci.2014.04.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Revised: 04/25/2014] [Accepted: 04/30/2014] [Indexed: 06/03/2023]
Abstract
Strigolactones produced by various plant species are involved in the development of different plant parts. They are also exuded by plant roots to the rhizosphere, where they are involved in the induction of seed germination of the parasitic plants Striga and Orobanche, hyphal branching of the symbiotic arbuscular mycorrhizal fungi (AMF), and the symbiotic interaction with Rhizobium. In the present discussion paper, the essentialness of strigolactones as communication signals in these plant interactions is discussed in view of the existence of other plant-derived substances that are able to promote these plant interactions. In addition, the importance of strigolactones for determination of interaction specificity is discussed based on current knowledge on strigolactone composition, perception and delivery. The different activities of strigolactones in plant development and in the rhizosphere suggest their possible use in agriculture. However, despite efforts made in this direction, there is no current, practical implementation. Possible reasons for the encountered difficulties and suggested solutions to promote strigolactone use in agriculture are discussed.
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Affiliation(s)
- Hinanit Koltai
- Institute of Plant Sciences, ARO, Volcani Center, Bet-Dagan 50250, Israel.
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33
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Aly R, Dubey NK, Yahyaa M, Abu-Nassar J, Ibdah M. Gene silencing of CCD7 and CCD8 in Phelipanche aegyptiaca by tobacco rattle virus system retarded the parasite development on the host. PLANT SIGNALING & BEHAVIOR 2014; 9:e29376. [PMID: 25763619 PMCID: PMC4203721 DOI: 10.4161/psb.29376] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Revised: 05/27/2014] [Accepted: 05/27/2014] [Indexed: 05/11/2023]
Abstract
Strigolactones are phytohormones that stimulate seed germination of parasitic plants including Phelipanche aegyptiaca. Strigolactones are derived from carotenoids via a pathway involving the carotenoid cleavage dioxygenases CCD7 and CCD8. We report here identification of PaCCD7 and PaCCD8 orthologous genes from P. aegyptiaca. Expression analysis of PaCCD7 and PaCCD8 genes showed significant variation in their transcript levels in seeds and tubercles of P. aegyptiaca at different developmental stages. These two parasitic PaCCD7 and PaCCD8 genes were silenced in P. aegyptiaca using a trans-silencing approach in Nicotiana benthamiana. The transient knock-down of PaCCD7 and PaCCD8 inhibited tubercle development and the infestation process in host plants. Our results suggest an important role of the strigolactone associated genes (PaCCD7 and PaCCD8) in the parasite life cycle.
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Affiliation(s)
| | | | | | - Jackline Abu-Nassar
- NeweYaar Research Center; Agriculture Research Organization; Ramat Yishay, Israel
| | - Mwafaq Ibdah
- NeweYaar Research Center; Agriculture Research Organization; Ramat Yishay, Israel
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