Analysis of Sugars in Squash Xylem Sap

Iwai, Hiroaki; Usui, Masako; Hoshino, Haruko; Kamada, Hiroshi; Matsunaga, Toshiro; Kakegawa, Koichi; Ishii, Tadashi; Satoh, Shinobu

doi:10.1093/pcp/pcg075

Cited by 37 publications

(33 citation statements)

References 44 publications

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“…Standard media used to grow Fusarium (potato dextrose broth [PDB, rich] and Czapek Dox [CDB, minimal]) did not result in high expression levels of SIX1, but on a minimal medium based on 3% sucrose and 1% KNO 3 the SIX1 expression level was comparable to that of FEM1. Media designed to resemble plant and/or xylem sap conditions (Dixon and Pegg, 1972;Iwai et al, 2003;Joosten et al, 1990) did not induce SIX1 expression. In plants, on the other hand, SIX1 expression greatly exceeded FEM1 transcript levels (Fig.…”

Section: Six1 Is Strongly Expressed In Planta But Not or Very Weakly mentioning

confidence: 85%

Expression of effector gene SIX1 of Fusarium oxysporum requires living plant cells

Does

Duyvesteijn

Goltstein

et al. 2008

Fungal Genetics and Biology

100

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General rightsIt is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: http://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. b s t r a c tFusarium oxysporum is an asexual, soil inhabiting fungus that comprises many different formae speciales, each pathogenic towards a different host plant. In absence of a suitable host all F. oxysporum isolates appear to have a very similar lifestyle, feeding on plant debris and colonizing the rhizosphere of living plants. Upon infection F. oxysporum switches from a saprophytic to an infectious lifestyle, which probably includes the reprogramming of gene expression. In this work we show that the expression of the known effector gene SIX1 of F. oxysporum f. sp. lycopersici is strongly upregulated during colonization of the host plant. Using GFP (green fluorescent protein) as reporter, we show that induction of SIX1 expression starts immediately upon penetration of the root cortex. Induction requires living plant cells, but is not host specific and does not depend on morphological features of roots, since plant cells in culture can also induce SIX1 expression. Taken together, F. oxysporum seems to be able to distinguish between living and dead plant material, preventing unnecessary switches from a saprophytic to an infectious lifestyle.

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Section: Six1 Is Strongly Expressed In Planta But Not or Very Weakly mentioning

confidence: 85%

Expression of effector gene SIX1 of Fusarium oxysporum requires living plant cells

Does

Duyvesteijn

Goltstein

et al. 2008

Fungal Genetics and Biology

100

View full text Add to dashboard Cite

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“…1, A and B), which was probably caused by changes in the physiological concentrations of natural surfactants (Iwai et al, 2003;Ligat et al, 2011;Schenk et al, 2017) or, to less extent, of ions. Accordingly, g of the xylem sap was negatively related to its osmolality (Fig.…”

Section: Discussionmentioning

confidence: 99%

“…Besides the presence of non-surface-active molecules (Andersen et al, 1995;Schill and Hartung, 1996), such as inorganic salts and sugars that might increase g and alcohols that might decrease g, also natural surface-active compounds, such as phospholipids, proteins, and glycoproteins, known for decreasing g, were detected in the xylem sap (Iwai et al, 2003;Ligat et al, 2011;Schenk et al, 2017). ChristensenDalsgaard et al (2011) also found g of extracted xylem sap to steeply decrease until leveling off, thus indicating the presence of amphiphilic surfactants.…”

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confidence: 99%

Xylem Sap Surface Tension May Be Crucial for Hydraulic Safety

et al. 2017

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The surface tension (g) of xylem sap plays a key role in stabilizing air-water interfaces at the pits between water-and gas-filled conduits to avoid air seeding at low water potentials. We studied seasonal changes in xylem sap g in Picea abies and Pinus mugo growing at the alpine timberline. We analyzed their vulnerability to drought-induced embolism using solutions of different g and estimated the potential effect of seasonal changes in g on hydraulic vulnerability. In both species, xylem sap g showed distinct seasonal courses between about 50 and 68 mN m 21 . Solutions with low g caused higher vulnerability to drought-induced xylem embolism. The water potential at 50% loss of hydraulic conductivity in P. abies and P. . This indicates up to about 1 MPa seasonal variation in 50% loss of hydraulic conductivity. The results revealed pronounced effects of changes in xylem sap g on the hydraulic safety of trees in situ. These effects also are relevant in vulnerability analyses, where the use of standard solutions with high g overestimates hydraulic safety. Thus, g should be considered carefully in hydraulic studies.

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“…Hydrophobic properties of xylem conduit walls have been shown by contact angles between menisci of sap or water and wall surfaces that deviate substantially from zero (Zwieniecki and Holbrook, 2000;Kohonen, 2006;Brodersen et al, 2010;McCully et al, 2014) and based on probes used to characterize wall surface properties (McCully et al, 2014). The evidence for xylem surfactants also should not have come as a surprise, because it is well known that xylem sap contains a large variety of molecules with potential surface-active properties, such as many different proteins (Buhtz et al, 2004;Dafoe and Constabel, 2009;Krishnan et al, 2011;Ligat et al, 2011;Zhang et al, 2015), glycoproteins (Iwai et al, 2003), and possibly phospholipids, which have been found in apoplastic fluid but not specifically in xylem sap to date (Gonorazky et al, 2012).…”

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confidence: 99%

Xylem Surfactants Introduce a New Element to the Cohesion-Tension Theory

et al. 2016

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Vascular plants transport water under negative pressure without constantly creating gas bubbles that would disable their hydraulic systems. Attempts to replicate this feat in artificial systems almost invariably result in bubble formation, except under highly controlled conditions with pure water and only hydrophilic surfaces present. In theory, conditions in the xylem should favor bubble nucleation even more: there are millions of conduits with at least some hydrophobic surfaces, and xylem sap is saturated or sometimes supersaturated with atmospheric gas and may contain surface-active molecules that can lower surface tension. So how do plants transport water under negative pressure? Here, we show that angiosperm xylem contains abundant hydrophobic surfaces as well as insoluble lipid surfactants, including phospholipids, and proteins, a composition similar to pulmonary surfactants. Lipid surfactants were found in xylem sap and as nanoparticles under transmission electron microscopy in pores of intervessel pit membranes and deposited on vessel wall surfaces. Nanoparticles observed in xylem sap via nanoparticle-tracking analysis included surfactant-coated nanobubbles when examined by freeze-fracture electron microscopy. Based on their fracture behavior, this technique is able to distinguish between dense-core particles, liquid-filled, bilayer-coated vesicles/liposomes, and gas-filled bubbles. Xylem surfactants showed strong surface activity that reduces surface tension to low values when concentrated as they are in pit membrane pores. We hypothesize that xylem surfactants support water transport under negative pressure as explained by the cohesion-tension theory by coating hydrophobic surfaces and nanobubbles, thereby keeping the latter below the critical size at which bubbles would expand to form embolisms.

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Analysis of Sugars in Squash Xylem Sap

Cited by 37 publications

References 44 publications

Expression of effector gene SIX1 of Fusarium oxysporum requires living plant cells

Expression of effector gene SIX1 of Fusarium oxysporum requires living plant cells

Xylem Sap Surface Tension May Be Crucial for Hydraulic Safety

Xylem Surfactants Introduce a New Element to the Cohesion-Tension Theory

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