Search results for: M. P. You

Items from 1 to 20 out of 23 results

article

Geographic location and year determine virulence, and year determines genetic change, in populations of Neopseudocercosporella capsellae

T. Murtza, M. P. You, M. J. Barbetti

White leaf spot (Neopseudocercosporella capsellae) can be severe and problematic worldwide across both horticultural and oilseed Brassicaceae, including susceptible rapeseed. In this study, 82 isolates from 2015 and 106 isolates from across Australia in 2016 were first assessed for their virulence against three different rapeseed (Brassica napus) cultivars. For both years there were significant (P...

article

Manipulating the ecosystem enables management of soilborne pathogen complexes in annual legume forage systems

M. P. You, M. J. Barbetti

Plant Pathology > 68 > 3 > 454 - 469

Studies were undertaken to examine the potential for manipulating the ecosystem by altering forage species composition, intensity of grazing or by adding Rhizobium, to enhance productivity of subterranean clover (Trifolium subterraneum) forages affected by the soilborne pathogens Pythium irregulare and Rhizoctonia solani. Levels of tap and lateral root disease on clover and its productivity were differentially...

article

Incidence, pathogenicity and diversity of Alternaria spp. associated with alternaria leaf spot of canola (Brassica napus) in Australia

H. F. D. Al‐Lami, M. P. You, M. J. Barbetti

Plant Pathology > 68 > 3 > 492 - 503

Studies were undertaken to determine Alternaria spp. associated with leaf spot symptoms on canola (Brassica napus) in two cropping seasons (2015, 2016) across southern Australia. Major allergen Alt a1 and plasma membrane ATPase genes were used to identify Alternaria spp. In 2015, 112 isolates of seven Alternaria spp. were obtained, with A. metachromatica predominating. In 2016, 251 isolates of 12...

article

Pathotypes and phylogenetic variation determine downy mildew epidemics in Brassica spp. in Australia

A. E. Mohammed, M. P. You, H. F. D. Al‐lami, M. J. Barbetti

Plant Pathology > 67 > 7 > 1514 - 1527

Isolates of Hyaloperonospora brassicae inoculated onto cotyledons of 28 diverse Brassicaceae genotypes, 13 from Brassica napus, two from B. juncea, five from B. oleracea, two from Eruca vesicaria, and one each from B. nigra, B. carinata, B. rapa, Crambe abyssinica, Raphanus sativus and R. raphanistrum, showed significant effects (P ≤ 0.001) of isolate, host and their interaction. Host responses ranged...

article

Critical factors driving aphanomyces damping‐off and root disease in clover revealed and explained using linear and generalized linear models and boosted regression trees

M. P. You, K. Rensing, M. Renton, M. J. Barbetti

Plant Pathology > 67 > 6 > 1374 - 1387

Subterranean clover (Trifolium subterraneum) is an important forage legume in Mediterranean regions worldwide. Aphanomyces damping‐off and root disease (Aphanomyces trifolii) poses significant threat to its persistence and productivity. Studies were conducted to define how environmental explanatory variables (temperature, soil type, moisture, nutrition) and variety influence disease severity and consequent...

article

Extended survival of Puccinia graminis f. sp. tritici urediniospores: implications for biosecurity and on‐farm management

P. Barua, M. P. You, K. L. Bayliss, V. Lanoiselet, more

Plant Pathology > 67 > 4 > 799 - 809

Puccinia graminis f. sp. tritici (Pgt), the causal organism of stem rust, is of global importance across wheat‐growing countries. However, some epidemics commence without the obvious presence of ‘alternate’ or ‘green bridge’ hosts, suggesting urediniospores can survive in the absence of suitable host plants for many weeks. Testing a range of inert material types, including metals, plastics, fabrics...

article

Plant age and ambient temperature: significant drivers for powdery mildew (Erysiphe cruciferarum) epidemics on oilseed rape (Brassica napus)

M. B. Uloth, M. P. You, M. J. Barbetti

Plant Pathology > 67 > 2 > 445 - 456

Powdery mildew (Erysiphe cruciferarum) is an important disease in oilseed rape crops worldwide, but of sporadic importance in most southern Australian crops. Six Brassica napus cultivars were exposed to E. cruciferarum simultaneously in four plant age cohorts. First symptoms of powdery mildew appeared 9 days after inoculation (dai) on the oldest plants [42 days after seeding (das)], but 44 dai in...

article

Expression of defence‐related genes in stems and leaves of resistant and susceptible field pea (Pisum sativum) during infection by Phoma koolunga

H. S. Tran, M. P. You, M. J. Barbetti

Plant Pathology > 67 > 1 > 156 - 166

The differential expression of 13 defence‐related genes during Phoma koolunga infection of stems and leaves of susceptible versus resistant field pea (Pisum sativum) was determined using qRT‐PCR. Expression, in terms of relative mRNA level ratios, of genes encoding ferredoxin NADP oxidoreductase, 6a‐hydroxymaackiain methyltransferase (hmm6), chalcone synthase (PSCHS3) and ascorbate peroxidase in leaves...

article

Cultivation offers effective management of subterranean clover damping‐off and root disease

M. P. You, K. Guo, D. Nicol, D. Kidd, more

Grass and Forage Science > 72 > 4 > 785 - 793

Soil cultivation studies involving subterranean clover pastures were undertaken utilizing field cores from five farms and two in‐field trials. Tap and lateral root disease in cores was less (p < .001) severe and root and shoot weights greater (p < .001) following simulated cultivation. Germination and severity of root disease were both affected (p < .005) by three‐way interactions with cultivation,...

article

Long‐term viability of the northern anthracnose pathogen, Kabatiella caulivora, facilitates its transportation and spread

P. Barua, M. P. You, K. L. Bayliss, V. Lanoiselet, more

Plant Pathology > 66 > 9 > 1463 - 1471

The conidia and resting hyphae of the northern anthracnose pathogen of Trifolium species, Kabatiella caulivora, were effectively carried by, and maintained long‐term viability on, a range of materials, including metals, fabrics, woods and plastics. Conidia and hyphae became thick‐walled and melanized with time. There were significant (P < 0.001) differences in conidia/resting hyphae survival between...

article

Severity of phytophthora root rot and pre‐emergence damping‐off in subterranean clover influenced by moisture, temperature, nutrition, soil type, cultivar and their interactions

M. P. You, M. J. Barbetti

Plant Pathology > 66 > 7 > 1162 - 1181

Studies were carried out in controlled environment rooms reflecting field situations. In the presence of the devastating soilborne pathogen Phytophthora clandestina, subterranean clover (Trifolium subterraneum) seedling emergence was significantly affected by moisture, soil type, temperature and cultivar. The level of rotting of tap and lateral roots was significantly affected by nutrition, soil type,...

article

Unique infection structures produced by Pseudocercosporella capsellae on oilseed crops Brassica carinata, B. juncea and B. napus in Western Australia

N. Gunasinghe, M. P. You, P. Clode, G. R. Cawthray, more

Plant Pathology > 66 > 2 > 304 - 315

White leaf spot disease (Pseudocercosporella capsellae) is widespread across oilseed, vegetable and forage brassicas. Light (LM) and scanning electron (SEM) microscope studies were undertaken to investigate host–pathogen interactions on cotyledons of resistant and susceptible Brassica carinata, B. juncea and B. napus. Under LM, unique brown structures were present, particularly on susceptible genotypes,...

article

Infection process of Phoma koolunga on stem and leaf tissue of resistant and susceptible field pea (Pisum sativum)

H. S. Tran, M. P. You, T. N. Khan, M. J. Barbetti

Plant Pathology > 66 > 2 > 212 - 222

This study investigates the infection process of Phoma koolunga on field pea (Pisum sativum) stems and leaves using different susceptible and resistant pea genotypes for each tissue, viz. 05P778‐BSR‐701 (resistant) and 06P830‐(F5)‐BSR‐5 (susceptible) for stems and ATC 866 (resistant) and ATC 5347 (susceptible) for leaves. On both resistant and susceptible genotypes, light and scanning electron microscopy...

article

Mechanisms of resistance in Brassica carinata, B. napus and B. juncea to Pseudocercosporella capsellae

N. Gunasinghe, M. P. You, P. L. Clode, M. J. Barbetti

Plant Pathology > 65 > 6 > 888 - 900

Studies were undertaken to compare susceptible and resistant host responses to Pseudocercosporella capsellae in cotyledons of Brassica carinata, B. juncea and B. napus in order to define the mechanisms of resistance in these three species. On both resistant and susceptible hosts, hyphal penetration was always through stomatal openings and without infection pegs or appressoria. On resistant B. carinata...

article

Host resistances to Aphanomyces trifolii root rot of subterranean clover: first opportunity to successfully manage this severe pasture disease

M. P. You, T. A. O'Rourke, K. Foster, R. Snowball, more

Plant Pathology > 65 > 6 > 901 - 913

Subterranean clover (Trifolium subterraneum) is an important pasture legume in Australia (29 million ha) and elsewhere. However, severe pasture decline occurs in association with several root pathogens, including Aphanomyces trifolii, that has been misidentified for decades as A. euteiches until recently confirmed as A. trifolii. A series of controlled environment experiments was undertaken to identify...

article

Phenotypic and phylogenetic studies associated with the crucifer white leaf spot pathogen, Pseudocercosporella capsellae, in Western Australia

N. Gunasinghe, M. P. You, M. J. Barbetti

Plant Pathology > 65 > 2 > 205 - 217

Pseudocercosporella capsellae (white leaf spot disease) is an important disease on crucifers. Fifty‐four single‐conidial isolates collected from Brassica juncea (Indian mustard), B. napus (oilseed rape), B. rapa (turnip), and Raphanus raphanistrum (wild radish) across Western Australia were investigated for differences in pathogenicity and virulence using cotyledon screening tests, genetic differences...

article

Temperature adaptation in isolates of Sclerotinia sclerotiorum affects their ability to infect Brassica carinata

M.B. Uloth, M. P. You, G. Cawthray, M. J. Barbetti

Plant Pathology > 64 > 5 > 1140 - 1148

Sclerotinia stem rot (Sclerotinia sclerotiorum) is a serious disease in oilseed Brassica crops worldwide. In this study, temperature adaptation in isolates of S. sclerotiorum collected from differing climatic zones is reported for the first time on any crop. Sclerotinia sclerotiorum isolates from oilseed rape (Brassica napus) crops in warmer northern agricultural regions of Western Australia (WW3,...

article

Molecular variation among isolates belonging to eight races of Phytophthora clandestina

X. L. Ma, P. Kong, M. P. You, Hua Li, more

Australasian Plant Pathology > 2009 > 38 > 6 > 608-616

Phytophthora clandestina, a serious pathogen of subterranean clover (Trifolium subterraneum), has only been recorded in Australia. A rapid method was used to characterise genetic variation among 61 isolates of P. clandestina belonging to eight pathogenic races based on DNA sequencing and single-strand conformation polymorphism (SSCP) analyses of the β-tubulin gene of the pathogen. The β-tubulin gene...

article

A new leaf blight disease of Trifolium dasyurum caused by Botrytis fabae

M. P. You, H. A. Yang, K. Sivasithamparam, M. J. Barbetti

European Journal of Plant Pathology > 2009 > 123 > 1 > 99-103

A new disease was observed on Trifolium dasyurum, with symptoms beginning as a halo spot and developing into a leaf blight. The causal organism was identified by microscopy and DNA sequence studies as Botrytis fabae. This strain of B. fabae was also demonstrated to cause disease on foliage of a range of pulse crops, including Vicia faba, Pisum sativum, and Lens culinaris. This study demonstrates the...

article

The association of necrotrophic fungal pathogens and plant parasitic nematodes with the loss of productivity of annual medic-based pastures in Australia and options for their management

M. J. Barbetti, I. T. Riley, M. P. You, Hua Li, more

Australasian Plant Pathology > 2006 > 35 > 6 > 691-706

Annual medics (annual Medicago spp.) are often an integral component of dry-land farming and cropping systems worldwide, including significant areas of the winter rainfall regions of southern Australia. Necrotrophic fungal pathogens frequently dominate such areas because of the ease of survival of these trash-and soilborne pathogens on infested residues over the relatively dry summer period. Necrotrophic...

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Search results for: M. P. You

Geographic location and year determine virulence, and year determines genetic change, in populations of Neopseudocercosporella capsellae

Manipulating the ecosystem enables management of soilborne pathogen complexes in annual legume forage systems

Incidence, pathogenicity and diversity of Alternaria spp. associated with alternaria leaf spot of canola (Brassica napus) in Australia

Pathotypes and phylogenetic variation determine downy mildew epidemics in Brassica spp. in Australia

Critical factors driving aphanomyces damping‐off and root disease in clover revealed and explained using linear and generalized linear models and boosted regression trees

Extended survival of Puccinia graminis f. sp. tritici urediniospores: implications for biosecurity and on‐farm management

Plant age and ambient temperature: significant drivers for powdery mildew (Erysiphe cruciferarum) epidemics on oilseed rape (Brassica napus)

Expression of defence‐related genes in stems and leaves of resistant and susceptible field pea (Pisum sativum) during infection by Phoma koolunga

Cultivation offers effective management of subterranean clover damping‐off and root disease

Long‐term viability of the northern anthracnose pathogen, Kabatiella caulivora, facilitates its transportation and spread

Severity of phytophthora root rot and pre‐emergence damping‐off in subterranean clover influenced by moisture, temperature, nutrition, soil type, cultivar and their interactions

Unique infection structures produced by Pseudocercosporella capsellae on oilseed crops Brassica carinata, B. juncea and B. napus in Western Australia

Infection process of Phoma koolunga on stem and leaf tissue of resistant and susceptible field pea (Pisum sativum)

Mechanisms of resistance in Brassica carinata, B. napus and B. juncea to Pseudocercosporella capsellae

Host resistances to Aphanomyces trifolii root rot of subterranean clover: first opportunity to successfully manage this severe pasture disease

Phenotypic and phylogenetic studies associated with the crucifer white leaf spot pathogen, Pseudocercosporella capsellae, in Western Australia

Temperature adaptation in isolates of Sclerotinia sclerotiorum affects their ability to infect Brassica carinata

Molecular variation among isolates belonging to eight races of Phytophthora clandestina

A new leaf blight disease of Trifolium dasyurum caused by Botrytis fabae

The association of necrotrophic fungal pathogens and plant parasitic nematodes with the loss of productivity of annual medic-based pastures in Australia and options for their management

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