Signal and nutrient exchange at biotrophic plant–fungus interfaces

Hahn, Matthias; Mendgen, Kurt

doi:10.1016/s1369-5266(00)00180-1

Cited by 126 publications

(91 citation statements)

References 53 publications

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“…Nevertheless, secretory activity is required by both partners to form the interface layers that are observed in biotrophic interactions. They contribute in an unknown way to the maintenance of compatibility and to the lack of host defense mechanisms [35,45].…”

Section: Resultsmentioning

confidence: 99%

“…AAT1p is a proton symporter with highest activities for histidine and lysine [34]. The AAT2-encoded protein shows high similarity to AAT1p (55.1% identity) and was detected by immunofluorescence in haustoria only [35]. AAT3 was found to encode a low-specificity amino-acid-proton symporter with a preference for S-containing amino acids (C. Struck et al, unpublished).…”

Section: Biotrophic Developmentmentioning

confidence: 99%

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Plant infection and the establishment of fungal biotrophy

Mendgen

Hahn

2002

Trends in Plant Science

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367

236

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To exploit plants as living substrates, biotrophic fungi have evolved remarkable variations of their tubular cells, the hyphae. They form infection structures such as appressoria, penetration hyphae and infection hyphae to invade the plant with minimal damage to host cells. To establish compatibility with the host, controlled secretory activity and distinct interface layers appear to be essential. Colletotrichum species switch from initial biotrophic to necrotrophic growth and are amenable to mutant analysis and molecular studies. Obligate biotrophic rust fungi can form the most specialized hypha: the haustorium. Gene expression and immunocytological studies with rust fungi support the idea that the haustorium is a transfer apparatus for the long-term absorption of host nutrients.

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Section: Resultsmentioning

confidence: 99%

Section: Biotrophic Developmentmentioning

confidence: 99%

Plant infection and the establishment of fungal biotrophy

Mendgen

Hahn

2002

Trends in Plant Science

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367

236

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“…However, no mechanism has been identified by which filamentous eukaryotic pathogens, such as fungi and oomycetes, deliver effectors to the host cytoplasm. Many oomycete and fungal pathogens, especially those that are biotrophic or hemibiotrophic, form differentiated feeding structures inside host cells called haustoria (Hahn and Mendgen, 2001;Hardham, 2007). The hyphae displace, but do not penetrate, the plant plasma cell membrane, resulting in the formation of a specialized haustorial interface consisting of the plasma cell membranes of the two organisms, separated by a modified pathogen cell wall (Figure 8) (Hahn and Mendgen, 2001;Hardham, 2007).…”

Section: Discussionmentioning

confidence: 99%

“…Many oomycete and fungal pathogens, especially those that are biotrophic or hemibiotrophic, form differentiated feeding structures inside host cells called haustoria (Hahn and Mendgen, 2001;Hardham, 2007). The hyphae displace, but do not penetrate, the plant plasma cell membrane, resulting in the formation of a specialized haustorial interface consisting of the plasma cell membranes of the two organisms, separated by a modified pathogen cell wall (Figure 8) (Hahn and Mendgen, 2001;Hardham, 2007). Haustoria are an obvious site for the release of effector proteins from the pathogen into the plant tissue, as the secreted effectors will be concentrated in close proximity with the plant plasma cell membrane.…”

Section: Discussionmentioning

confidence: 99%

RXLR-Mediated Entry of Phytophthora sojae Effector Avr1b into Soybean Cells Does Not Require Pathogen-Encoded Machinery

et al. 2008

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Effector proteins secreted by oomycete and fungal pathogens have been inferred to enter host cells, where they interact with host resistance gene products. Using the effector protein Avr1b of Phytophthora sojae, an oomycete pathogen of soybean (Glycine max), we show that a pair of sequence motifs, RXLR and dEER, plus surrounding sequences, are both necessary and sufficient to deliver the protein into plant cells. Particle bombardment experiments demonstrate that these motifs function in the absence of the pathogen, indicating that no additional pathogen-encoded machinery is required for effector protein entry into host cells. Furthermore, fusion of the Avr1b RXLR-dEER domain to green fluorescent protein (GFP) allows GFP to enter soybean root cells autonomously. The conclusion that RXLR and dEER serve to transduce oomycete effectors into host cells indicates that the >370 RXLR-dEER–containing proteins encoded in the genome sequence of P. sojae are candidate effectors. We further show that the RXLR and dEER motifs can be replaced by the closely related erythrocyte targeting signals found in effector proteins of Plasmodium, the protozoan that causes malaria in humans. Mutational analysis of the RXLR motif shows that the required residues are very similar in the motifs of Plasmodium and Phytophthora. Thus, the machinery of the hosts (soybean and human) targeted by the effectors may be very ancient.

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“…al.·Silvae Genetica (2008) 57-4/5, 235-242 2002HE and WOLYN, 2005). In the ECM symbiosis, on the other hand, the defence responses are thought to be weak or only transient (HAHN and MENDGEN, 2001). In a recent microarray assay of B. pendula-P. involutus ECMs, expression of the precursor genes of lignin biosynthesis, CCoAOMT (caffeoyl-coenzyme A 3-Omethyltransferase) and SAD (sinapyl alcohol dehydrogenase), as well as a gene homolog to a dirigent protein, were induced in specific developmental phases of ECMs (LE QUÉRÉ et al, 2005).…”

Section: Discussionmentioning

confidence: 99%

Paxillus involutus Forms an Ectomycorrhizal Symbiosis and Enhances Survival of PtCOMT-modified Betula pendula in vitro

Tiimonen¹,

Aronen²,

Laakso³

et al. 2008

Silvae Genetica

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The ability of the PtCOMT (caffeate/5-hydroxyferulate O-methyltransferase from Populus tremuloides L.) -modified Betula pendula Roth. lines to form symbiosis with an ectomycorrhizal (ECM) fungus Paxillus involutus Batsch Fr. was studied in vitro. Lignin precursor gene PtCOMT was introduced into two B. pendula clones under the control of the cauliflower mosaic virus 35S promoter or the promoter of the sunflower polyubiquitin gene UbB1. Of the four transgenic lines, one 35S-PtCOMT line (23) had a decreased syringyl/guaiacyl (S/G) ratio of root lignin, and two UbB1-PtCOMT lines (110 and 130) retarded root growth compared to the control clone. Both control clones and all transgenic lines were able to form ECMs with P. involutus, but the transgenic lines differed from the controls in the characteristics of the ECMs. The number of lateral roots covered with fungal hyphae and/or development of a Hartig net (HN) were reduced in line 23 with a decreased S/G ratio, and in lines 110 and 130 with slower root formation and changed root morphology, respectively. However, line 23 benefited more from the inoculation in lateral root formation than the control, and in lines 110 and 130 the percentage of viable plants increased most due to inoculation. The results show that B. pendula plants genetically transformed with the lignin gene PtCOMT could form mycorrhizal symbiosis regardless of changes in either the root S/G ratio or development. The benefits of the symbiosis were variable even in the closed in vitro system, and dependent on the clone or transgenic line and the ECM fungal symbiont.

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Signal and nutrient exchange at biotrophic plant–fungus interfaces

Cited by 126 publications

References 53 publications

Plant infection and the establishment of fungal biotrophy

Plant infection and the establishment of fungal biotrophy

RXLR-Mediated Entry of Phytophthora sojae Effector Avr1b into Soybean Cells Does Not Require Pathogen-Encoded Machinery

Paxillus involutus Forms an Ectomycorrhizal Symbiosis and Enhances Survival of PtCOMT-modified Betula pendula in vitro

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