Source-sink relationships in wheat leaves infected with powdery mildew. II. Changes in the regulation of the Calvin cycle

Wright, Derek P.; Baldwin, Brian C.; Shephard, M. C.; Scholes, J. D.

doi:10.1006/pmpp.1995.1056

Cited by 31 publications

(15 citation statements)

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“…Wright et al (1995) described the same effects with mildewed wheat. Both the rate and duration of grain growth are important for a good yield and both can be reduced by mildew or rust diseases (McGrath and Pennypacker 1991).…”

Section: Discussionmentioning

confidence: 53%

Arbuscular mycorrhiza increased the activity of a biotrophic leaf pathogen - is a compensation possible?

2001

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Arbuscular mycorrhizal barley-plants were more susceptible to the obligate biotrophic shoot pathogen Erysiphe graminis f. sp. hordei. In experiments under greenhouse and open-air conditions on leaves of mycorrhizal plants, the sporulation rate of the mildew fungus was more than twice that on control plants. However, mycorrhizal plants suffered less than non-mycorrhizal plants in terms of grain number, ear yield and thousand-grain weight. Disease-yield-relationship analysis showed that the symbiosis neutralised the positive correlation between disease severity and yield loss (up to 25% infected leaf area tested). After mildew infection, nitrogen in ears of nonmycorrhizal barley was higher because of an impaired starch accumulation during grain filling. In mycorrhizal plants, leaf disease did not impair either the quantity or quality of grain yield. This improved compensation in mycorrhizal plants was related to maintained photosynthetic capacity and a delay in pathogen-induced senescence. Thus filling of long-term storage pools (fructans in internodes) and consequently reallocation of these reserves during grain filling was improved. The results suggest that higher availability of energy and material during grain formation, together with longer physiological activity, were the basis of yield maintenance and, therefore, expression of mycorrhiza-induced tolerance towards the pathogen.

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Section: Discussionmentioning

confidence: 53%

Arbuscular mycorrhiza increased the activity of a biotrophic leaf pathogen - is a compensation possible?

2001

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“…Accordingly, both partners appear to activate their own invertases, providing strong support to the theory that infection by pathogens creates a new sink that competes with existing sinks ( Figure 3 ). As a consequence, hexoses accumulate in the apoplast, and are taken up by co-regulated hexose transporters (Wright et al, 1995; Clark and Hall, 1998). …”

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.

953

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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“…Plants infected with fungal biotrophic pathogens, including powdery mildew, exhibit a reduced rate of photosynthesis (Roberts and Walters 1988;Wright et al 1995b;Sabri et al 1997;Huang 2001;Akhkha et al 2003). Powdery mildew can reduce host photosynthesis by various mechanisms, including reduction of assimilating leaf area (Moriondo et al 2005), lower supply of light energy due to covering of the leaf surface by mycelium (Yurina et al 1996) and inhibition of CO 2 influx due to stomata closure (Gordon and Duniway 1982).…”

Section: Changes In Photosynthesis Of Host Plantsmentioning

confidence: 99%

“…Powdery mildew can also affect photosynthesis via changes in source-sink relations and nutrient remobilization towards infection sites (Scholes et al 1994;Wright et al 1995a;Abood and Lösel 2003). This can result in the inhibition of the Calvin cycle (Gordon and Duniway 1982;Scholes et al 1994;Wright et al 1995b) and in the inhibition of photosynthetic light reactions in thylakoid membranes (Magyarosy et al 1976). It has been suggested that the down-regulation of photosynthesis during powdery mildew infection is caused by higher activity of a cell-wall invertase, which leads to the accumulation of hexose Fig.…”

Section: Changes In Photosynthesis Of Host Plantsmentioning

confidence: 99%

“…Means and SD are shown, n=3 (*n=2); statistically significant differences are indicated by different letters. Fw -fresh weighs, Missing data for S. chmielewskii are caused by abscission of leaves sugars (Scholes et al 1994;Wright et al 1995b;Swarbrick et al 2006) and subsequently to feed-back inhibition of the expression of some photosynthetic genes (especially cab and rbcS) (Scholes et al 1994;Fotopoulos et al 2003;Swarbrick et al 2006).…”

Section: Changes In Photosynthesis Of Host Plantsmentioning

confidence: 99%

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Resistance mechanisms of wild tomato germplasm to infection of Oidium neolycopersici

et al. 2013

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Tomato powdery mildew (Oidium neolycopersici) is one of the most devastating diseases of cultivated tomatoes worldwide. Although the first epidemics were recorded more than 25 years ago many aspects of this host-pathogen interaction are still not well understood. Detailed morphological and molecular studies of the anamorphs confirmed that O. neolycopersici is phylogeneticaly close to Erysiphe aquilegiae var. ranunculi. Host range is rather broad, apart from Solanaceae hosts were found in the families Apocynaceae, Campanulaceae, Crassulaceae, Cistaceae, Cucurbitaceae, Linaceae, Malvaceae, Papaveraceae, Pedialiaceae, Scrophulariaceae, Valerianaceae a Violaceae. Non-host resistance within these families is not based on inhibition of formation of primary haustorium, however, on post-haustorial hypersensitive reponse and another type of non-hypersensitive resistance. Screening of wild Solanum species (previous Lycopersicon spp.) germplasm revealed valuable sources of resistance (S. habrochaites, S. pennellii, S. cheesmaniae, S. chilense, S. peruvianum). The main resistance mechanism was found to be a hypersensitive response (HR), in some cases followed by limited development of the pathogen. However, there is a broad variation in resistance response on the histological and cytological level. Interaction between many wild Solanum spp. and O. neolycopersici is race-specific, at least three races were differentiated. In some interspecific crosses (S. lycopersicum × S. habrochaites) adult plant resistance was observed. Biochemical studies focusing on production of reactive oxygen species (ROS) and peroxidase activity during infection of O. neolycopersici showed that production of ROS and activity of corresponding enzymes is related to activation of defence responses in genotypes of wild Solanum sect. Lycopersicon. The significance of nitric oxide (NO) in O. neolycopersici pathogenesis was supported by experiments with NO donors and scavengers. In moderately resistant genotype S. chmielewskii, treatment by heat stress caused slight deceleration of pathogen development, increased production of jasmonic acid (JA) and abscisic acid (ABA) and increased peroxidase activity in infected plants. The different degree of tomato resistance/ susceptibility did not markedly change the rate and extent of photosynthetic response to O. neolycopersici; only minimal impairment of photosynthesis was found in both susceptible and moderately resistant genotypes during the Harper Adams University, Newport, Shropshire TF10 8NB, UK first 9 days after inoculation. The accumulated evidence confirm a crucial role of localised increased production of ROS and reactive nitrogen species (RNS) in response to pathogen penetration into plant tissue and its involvement in the plant resistance responses including the initiation and progression of plant cell death in host wild Solanum species. Crucial points of further research are discussed.

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Source-sink relationships in wheat leaves infected with powdery mildew. II. Changes in the regulation of the Calvin cycle

Cited by 31 publications

References 0 publications

Arbuscular mycorrhiza increased the activity of a biotrophic leaf pathogen - is a compensation possible?

Arbuscular mycorrhiza increased the activity of a biotrophic leaf pathogen - is a compensation possible?

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

Resistance mechanisms of wild tomato germplasm to infection of Oidium neolycopersici

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