Effects of Wheat Genotype, Time After Inoculation, and Leaf Age on Conidia Production by<i>Drechslera tritici-repentis</i>

Riaz, Muhammad

doi:10.1094/phyto-81-1298

Cited by 15 publications

(11 citation statements)

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“…Other pathogens are known that preferentially infect new leaves, such as the eucalypt rust P. psidii, which is affected by host phenology (Xavier et al, 2001) and other pathosystems (Eshenaur & Milholland, 1989;Nita et al, 2003). On the other hand, there are pathogens that preferentially infect old leaves (Chang & Hwang, 2003;Cox and Hosford, 1987;Hosford et al, 1990;Hosford et al, 1987;Jonsson et al, 1998;Raymond et al, 1985;Riaz et al, 1991;Tekauz, 1986). Chang & Hwang (2003) observed that adlay plant leaf position and age had a significant influence on leaf blight severity, which was higher on the lower (older) leaves than on the upper (younger) leaves, regardless of growth stage and cultivar.…”

Section: Discussionmentioning

confidence: 99%

Effects of leaf position, surface, and entry sites on Quambalaria eucalypti infection in eucalypt

Máfia¹,

Alfenas²,

Ferreira³

et al. 2009

Trop. plant pathol.

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The objectives of this study were to determine the effects of leaf position, surface, and the need for entry sites, such as wounds, other pathogen lesions or natural openings, to promote infection of Quambalaria eucalypti in Eucalyptus spp. We carried out a series of artificial inoculations in wounded and unwounded leaves from seedlings of Eucalyptus globulus and two hybrid clones (UFV-100 �� E. grandis x E. urophylla and UFV-101 -E. saligna x E. maidenii). E. globulus was more susceptible to infection than clones UFV-100 and UFV-101. Artificial wounds greatly favored pathogen penetration. However, old lesions caused by Cylindrocladium pteridis and Puccinia psidii did not provide infection sites for Q. eucalypti. Differences in fungal spore germination and leaf surface colonization were not observed between expanding and fully expanded leaves. Q. eucalypti penetrated through the wounded leaves and we didn't observe direct penetration thought the epidermis. Stomata neither attracted nor repelled germ tube and somatic hyphae. Young expanding leaves were more susceptible to Q. eucalypti infection than fully expanded leaves located in the upper third of the plant. Infection took place preferentially on the abaxial leaf surface. Keywords: Eucalyptus, host-pathogen interaction, inoculation protocol, leaf spot. RESUMO Efeito da posição e superfície foliar sobre a infecção de Quambalaria eucalypti e determinação sítios de entrada em eucaliptoObjetivou-se, neste estudo, determinar os efeitos da posição da folha, superfície foliar e os sítios de entrada, assim como ferimentos, lesões de outros patógenos ou aberturas naturais sobre a infecção de Quambalaria eucalypti em Eucalyptus spp. Para isso, realizaram-se inoculações artificiais em folhas de mudas seminais de Eucalyptus globulus e dois clones híbridos de Eucalyptus (UFV-100 �� E. grandis x E. urophylla e UFV-101 -E. saligna x E. maidenii). E. globulus foi mais suscetível à infecção que os clones UFV-100 e UFV-101. Os ferimentos artificiais favoreceram a penetração do patógeno. Entretanto, lesões velhas causadas por Cylindrocladium pteridis e Puccinia psidii não foram sítios de entrada de Q. eucalypti. Não foram observadas diferenças na germinação de esporos e colonização entre folhas em expansão e completamente expandidas. Q. eucalypti penetrou em folhas com ferimentos. Contudo não foi possível observar a penetração direta através da epiderme. Folhas jovens foram mais suscetíveis à infecção de Q. eucalypti que folhas completamente expandidas no terço superior da planta. A infecção ocorreu preferencialmente na superfície abaxial da folha. Palavras-chave: Eucalyptus, interação patógeno-hospedeiro, protocolo de inoculação, mancha foliar.

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Section: Discussionmentioning

confidence: 99%

Effects of leaf position, surface, and entry sites on Quambalaria eucalypti infection in eucalypt

Máfia¹,

Alfenas²,

Ferreira³

et al. 2009

Trop. plant pathol.

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“…Conidia used for inoculation were obtained by transferring mycelial plugs from slants to V8 agar (Raymond et al 1985), which were kept in the dark at room temperature (20±2°C) for 5 days. The aerial mycelium was knocked down with a sterile, bent glass rod, and plates were placed 28 cm below four cool-white fluorescent tubes (about 35 l mol m À2 s À1 ) for 18 h at 20±2°C for conidiophore formation and then incubated in the dark for 24 h at 4°C for conidiation (Riaz et al 1991). Conidia were harvested from petri plates by adding distilled water to the surface of the plates and dislodging conidia with a sterile, bent metal rod, and then filtered through two layers of cheesecloth.…”

Section: Inoculation With Pyrenophoramentioning

confidence: 99%

“…For all treatments, plants were removed from the mist chamber after 48 h and placed on greenhouse benches until leaves were harvested on day 11. Pots were placed in shallow pans and watered from below to prevent free water from touching the leaves (Riaz et al 1991). …”

Section: Inoculation With Pucciniamentioning

confidence: 99%

“…The temperature regime in the growth chamber was 25°C during a 12-h photoperiod and 16°C during a 12-h dark period for 5 days. After this 5-day period, all segments of each leaf were cut into 1-cm pieces with scissors and blended in 15 ml of distilled water in a small blender (model 91-264, Dynamic Corporation of America, New Harford, CN, USA) for 15 s. After blending, three to four subsamples were taken using a pipette and placed on a grid designed for counting conidia (six units of 0.01 ml each) (Riaz et al 1991). The urediniospore counts were made using a hemacytometer.…”

Section: Assessment Of Sporulation On Leavesmentioning

confidence: 99%

“…Shoemaker), causal agent of tan spot in wheat and several wild grass species (Krupinsky 1992;C. M. Cox, in preparation), can survive as a saprophyte and produces significantly more conidia on older leaves than younger leaves (Riaz et al 1991;Fernandez et al 2002) because younger leaves are more resistant to the fungus (Raymond et al 1985;Cox and Hosford 1987).…”

Section: Introductionmentioning

confidence: 99%

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Competition, facilitation, and niche differentiation in two foliar pathogens

2005

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We studied competition between the obligate biotroph Puccinia triticina (designated here as Puccinia) and the facultative saprophyte Pyrenophora tritici-repentis (designated here as Pyrenophora) in older and younger leaves in a set of three host genotypes selected to be resistant to Puccinia only, Pyrenophora only, or neither. Age-related resistance is important for both of these pathogens. The facultative saprophyte Pyrenophora was generally a stronger competitor than the biotrophic Puccinia, even experiencing facilitation from the presence of Puccinia when Pyrenophora had the advantage of earlier inoculation. Both pathogen species produced the most spores when they were introduced before the competing species and more spores when introduced simultaneously compared to after the competitor. The pre-interactive niche of Puccinia was larger than the post-interactive niche and sporulation by Puccinia was substantially reduced in environments in which Pyrenophora had high sporulation rates. The pre-interactive niche of Pyrenophora was similar to the post-interactive niche and Pyrenophora had proportionally lower reductions in sporulation due to interspecific competition in the pre-interactive niche.

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Yield increases due to fungicide control of leaf blotch diseases in wheat and barley as a basis for IPM decision-making in the Nordic-Baltic region

et al. 2020

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Fungal plant diseases driven by weather factors are common in European wheat and barley crops. Among these, septoria tritici blotch (Zymoseptoria tritici), tan spot (Pyrenophora tritici-repentis), and stagonospora nodorum blotch (Parastagonospora nodorum) are common in the Nordic-Baltic region at variable incidence and severity both in spring and winter wheat fields. In spring barley, net blotch (Pyrenophora teres), scald (Rhynchosporium graminicola, syn. Rhynchosporium commune) and ramularia leaf spot (Ramularia collo-cygni) are common yield limiting foliar diseases. We analysed data from 449 field trials from 2007 to 2017 in wheat and barley crops in the Nordic-Baltic region and explored the differences in severity of leaf blotch diseases between countries and years, and the impact of the diseases on yield. In the experiments, septoria tritici blotch dominated in winter wheat in Denmark and southern Sweden; while in Lithuania, both septoria tritici blotch and tan spot were common. In spring wheat, stagonospora nodorum blotch dominated in Norway and tan spot in Finland. Net blotch and ramularia leaf blotch were the most severe barley diseases over large areas, while scald occurred more locally and had less yield impact in all countries. Leaf blotch diseases, with severity >50% at DC 73–77, caused an average yield loss of 1072 kg/ha in winter wheat and 1114 kg/ha in spring barley across all countries over 5 years. These data verify a large regional and yearly variation in disease severity, distribution and impact on yield, emphasizing the need to adapt fungicide applications to the actual need based on locally adapted risk assessment systems.

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Effects of Wheat Genotype, Time After Inoculation, and Leaf Age on Conidia Production byDrechslera tritici-repentis

Cited by 15 publications

References 0 publications

Effects of leaf position, surface, and entry sites on Quambalaria eucalypti infection in eucalypt

Effects of leaf position, surface, and entry sites on Quambalaria eucalypti infection in eucalypt

Competition, facilitation, and niche differentiation in two foliar pathogens

Yield increases due to fungicide control of leaf blotch diseases in wheat and barley as a basis for IPM decision-making in the Nordic-Baltic region

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