Glyphosate inhibits the translocation of green fluorescent protein and sucrose from a transgenic tobacco host to Cuscuta campestris Yunk.

Nadler-Hassar, Talia; Goldshmidt, Alexander; Rubin, Baruch; Wolf, Shmuel

doi:10.1007/s00425-004-1288-4

Cited by 18 publications

(9 citation statements)

References 13 publications

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“…The use of herbicides could also be a strategy to get rid of parasitic plants. Glyphosate, a systemic herbicide, is accumulated in the parasite due to its strong sink activity, without significant damage to the host (Nadler-Hassar et al, 2004). Glyphosate usually inhibits 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS), a key enzyme in the shikimate pathway.…”

Section: Effects Of Biotic Stressmentioning

confidence: 99%

Source-to-sink transport of sugar and regulation by environmental factors

Lemoine¹,

Camera²,

Atanassova³

et al. 2013

Front. Plant Sci.

974

655

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Source-to-sink transport of sugar is one of the major determinants of plant growth and relies on the efficient and controlled distribution of sucrose (and some other sugars such as raffinose and polyols) across plant organs through the phloem. However, sugar transport through the phloem can be affected by many environmental factors that alter source/sink relationships. In this paper, we summarize current knowledge about the phloem transport mechanisms and review the effects of several abiotic (water and salt stress, mineral deficiency, CO2, light, temperature, air, and soil pollutants) and biotic (mutualistic and pathogenic microbes, viruses, aphids, and parasitic plants) factors. Concerning abiotic constraints, alteration of the distribution of sugar among sinks is often reported, with some sinks as roots favored in case of mineral deficiency. Many of these constraints impair the transport function of the phloem but the exact mechanisms are far from being completely known. Phloem integrity can be disrupted (e.g., by callose deposition) and under certain conditions, phloem transport is affected, earlier than photosynthesis. Photosynthesis inhibition could result from the increase in sugar concentration due to phloem transport decrease. Biotic interactions (aphids, fungi, viruses…) also affect crop plant productivity. Recent breakthroughs have identified some of the sugar transporters involved in these interactions on the host and pathogen sides. The different data are discussed in relation to the phloem transport pathways. When possible, the link with current knowledge on the pathways at the molecular level will be highlighted.

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Section: Effects Of Biotic Stressmentioning

confidence: 99%

Source-to-sink transport of sugar and regulation by environmental factors

Lemoine¹,

Camera²,

Atanassova³

et al. 2013

Front. Plant Sci.

974

655

View full text Add to dashboard Cite

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“…A transgenic tomato expressing GFP in its companion cells under the At SUC2 promoter (Imlau et al, 1999 ) was used as a GFP host sensitive to glyphosate (GGST). In these plants, GFP is secreted into the phloem system and is transported throughout the plant along the source-to-sink pathway (Imlau et al, 1999 ; Nadler-Hassar et al, 2004 ; Birschwilks et al, 2006 ; Aly et al, 2011 ). A GFP host resistant to glyphosate (GGRT) was prepared by crossing GGST plants with GRT plants.…”

Section: Methodsmentioning

confidence: 99%

“…Since the shikimate pathway metabolizes about 30% of the assimilated carbon in photosynthetic plants (Maeda and Dudareva, 2012 ), it is reasonable to assume that related metabolic pathways may be affected within hours after the inhibition of EPSPS, due to the impairment of carbon metabolism (Servaites et al, 1987 ; Siehl, 1997 ; Orcaray et al, 2012 ). These changes, in turn, might lead to changes in source-sink relations and limit the translocation of solutes, as seen in autotrophic plants and also in a study of Cuscuta campestris parasitism, in which the translocation of [ 14 C]sucrose and GFP in the phloem were limited by glyphosate application to the host plants (Nadler-Hassar et al, 2004 ).…”

Section: Introductionmentioning

confidence: 99%

Secondary Effects of Glyphosate Action in Phelipanche aegyptiaca: Inhibition of Solute Transport from the Host Plant to the Parasite

et al. 2017

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It is currently held that glyphosate efficiently controls the obligate holoparasite Phelipanche aegyptiaca (Egyptian broomrape) by inhibiting its endogenous shikimate pathway, thereby causing a deficiency in aromatic amino acids (AAA). While there is no argument regarding the shikimate pathway being the primary site of the herbicide's action, the fact that the parasite receives a constant supply of nutrients, including proteins and amino acids, from the host does not fit with an AAA deficiency. This apparent contradiction implies that glyphosate mechanism of action in P. aegyptiaca is probably more complex and does not end with the inhibition of the AAA biosynthetic pathway alone. A possible explanation would lie in a limitation of the translocation of solutes from the host as a secondary effect. We examined the following hypotheses: (a) glyphosate does not affects P. aegyptiaca during its independent phase and (b) glyphosate has a secondary effect on the ability of P. aegyptiaca to attract nutrients, limiting the translocation to the parasite. By using a glyphosate-resistant host plant expressing the “phloem-mobile” green fluorescent protein (GFP), it was shown that glyphosate interacts specifically with P. aegyptiaca, initiating a deceleration of GFP translocation to the parasite within 24 h of treatment. Additionally, changes in the entire sugars profile (together with that of other metabolites) of P. aegyptiaca were induced by glyphosate. In addition, glyphosate did not impair germination or seedling development of P. aegyptiaca but begun to exert its action only after the parasite has established a connection to the host vascular system and became exposed to the herbicide. Our findings thus indicate that glyphosate does indeed have a secondary effect in P. aegyptiaca, probably as a consequence of its primary target inhibition—via inhibition of the translocation of phloem-mobile solutes to the parasite, as was simulated by the mobile GFP. The observed disruption in the metabolism of major sugars that are abundant in P. aegyptiaca within 48 h after glyphosate treatment provides a possible explanation for this inhibition of translocation and might reflect a critical secondary effect of the herbicide's primary action that results in loss of the parasite's superior sink for solutes.

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“…Subsequently, Nadler‐Hassar et al . () developed an experimental system that allowed characterisation of the kinetics of protein and sucrose transport from a host plant to C. campestris . In this system, tobacco plants expressing GFP in the sieve element–companion cell complex, under the control of the AtSUC2 promoter, were used to monitor the effect of the herbicide glyphosate on the trafficking of the fluorescent protein to the parasite.…”

Section: Movement Of Molecules and Macromolecules Between Host Plantsmentioning

confidence: 99%

Trafficking of molecules between parasitic plants and their hosts

Aly

2013

Weed Research

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Parasitic plants have evolved various methods of invading host plants. Some invade aerial parts, whereas others invade the roots to obtain necessary nutrients for their development. Phelipanche and Orobanche spp. (broomrapes) and Cuscuta spp. (dodders) are holoparasitic plants that subsist on roots and shoots, respectively, of a variety of agricultural crops. These weeds are able to connect directly with the vascular system of the host, thereby acquiring the water, minerals and carbohydrates necessary for their own growth and reproduction. This exploitation by parasitic plants often causes severe losses in yield quality and quantity of host crops. The key to an effective means for controlling parasitic plants lies in the development of resistant crops, supported by an improved understanding of broomrape and dodder biology. The

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Glyphosate inhibits the translocation of green fluorescent protein and sucrose from a transgenic tobacco host to Cuscuta campestris Yunk.

Cited by 18 publications

References 13 publications

Source-to-sink transport of sugar and regulation by environmental factors

Source-to-sink transport of sugar and regulation by environmental factors

Secondary Effects of Glyphosate Action in Phelipanche aegyptiaca: Inhibition of Solute Transport from the Host Plant to the Parasite

Trafficking of molecules between parasitic plants and their hosts

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