Epiphytic Survival of Pseudomonas syringae on Hairy Vetch in Relation to Epidemiology of Bacterial Brown Spot of Bean in Wisconsin

Ercolani, G. L.

doi:10.1094/phyto-64-1330

Cited by 72 publications

(34 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Pseudomonas fluorescens is not known as a phytopathogen, although other members ofthe group such as P. svringae are known foliar pathogens which survive in association with their host plant (Ercolani et al, 1974).…”

Section: Discussionmentioning

confidence: 99%

The distribution of some fungal and bacterial endophytes in maize (Zea mays L.)

1992

View full text Add to dashboard Cite

SUMMARYEndophytic bacteria and fungi were isolated from healthy maize plants collected in a field in Devon. The average bacterial counts in the stem core tissues showed that the plant parts closer to the soil were more heavily colonized by bacteria than those near the top of the plants, and that the lower and middle part of the stems hosted the most frequently isolated bacterial species. Of the fungal species isolated, 12 had a relative importance of more than 10°o m the core, 15 in the epidermis, and only 5 in the leaves. In general the distribution patterns were different among the three tissue types studied, with core and epidermis of the stems showing almost equal colonization frequencies and the leaves being most heavily colonized. More fungal species were recovered from the core and epidermis of the stem than from the leaves. The fungi most frequently isolated showed some patterns of tissue specificity, with Alternaria alternata almost exclusively associated with the leaves and Aureobasidium pulhilans var. melanigerum most often present in the epidermal tissues.Assays showed low fungal colonization of seeds taken from freshly matured cobs and of seeds dried for 8 wk before testing, in contrast to higher colonization frequencies observed for the seeds used for planting. The mean values for fungal isolations in the stem pieces mostly in contact with the soil flora or close to the ground were lower than those of the more centrally placed sections. These areas of low fungal infection yielded the highest bacteriai counts. The potential role of bacterial endophytes in biological control is briefly discussed.

show abstract

Section: Discussionmentioning

confidence: 99%

The distribution of some fungal and bacterial endophytes in maize (Zea mays L.)

1992

View full text Add to dashboard Cite

show abstract

“…26 of E. herbicola (13). Field isolates were selected as discrete colonies from dilution platings of leaf washings on nutrient agar containing 2.5% glycerol or on modified Crosse's medium (6). P. syringae formed characteristic light blue, domed colonies on modified Crosse's medium; E. herbicola isolates active in ice nucleation formed mucoid bluish colonies with yellow patches after 4 d on this medium.…”

Section: Methodsmentioning

confidence: 99%

Bacterial Ice Nucleation: A Factor in Frost Injury to Plants

Lindow

Arny²,

Upper³

1982

Plant Physiol.

274

209

View full text Add to dashboard Cite

Heterogeneous ice nuclei are necessary, and the common epiphytic ice nucleation active (INA) bacteria Pseudomonas syringae van Hall and Erwinia herbicola (Lihnis) Dye are sufficient to incite frost injury to sensitive plants at -5C. The ice nucleation activity of the bacteria occurs at the same temperatures at which frost injury to sensitive plants occurs in nature. Bacterial ice nucleation on leaves can be detected at about -2°C, whereas the leaves themselves, ie. without INA bacteria, contain nuclei active only at much lower temperatures. The temperature at which injury to plants occurs is predictable on the basis of the ice nucleation activity of leaf discs, which in turn depends on the number and ice nucleation activity of their resident bacteria. Bacterial isolates which are able to incite injury to corn at -5°C are always active as ice nuclei at -5°C. INA bacteria incited frost injury to all of the species of sensitive plants tested.

show abstract

“…Although disease causation is of central importance from the perspective of humans, it is only one of several interactions that occur between Pss and its host. In the field, the bacterium is able to multiply and survive for many generations on leaf surfaces of host and nonhost plants, similar to the numerous nonpathogenic bacteria that exist as epiphytes in the phyllosphere (1,3,4).…”

mentioning

confidence: 99%

Role of the Hrp type III protein secretion system in growth of Pseudomonas syringae pv. syringae B728a on host plants in the field

Hirano

Charkowski

Collmer

et al. 1999

Proc. Natl. Acad. Sci. U.S.A.

101

View full text Add to dashboard Cite

ABSTRACThrp genes are reportedly required for pathogenicity in Pseudomonas syringae pv. syringae (Pss) and other phytopathogenic bacterial species. A subset of these genes encodes a type III secretion system through which virulence factors are thought to be delivered to plant cells. In this study, we sought to better understand the role that hrp genes play in interactions of Pss with its host as they occur naturally under field conditions. Population sizes of hrp mutants with defects in genes that encode components of the Hrp secretion system (⌬hrcC::nptII and hrpJ:: ⍀Spc) and a protein secreted via the system (⌬hrpZ::nptII) were similar to B728a on germinating seeds. However, phyllosphere (i.e., leaf) population sizes of the hrcC and hrpJ secretion mutants, but not the hrpZ mutant, were significantly reduced relative to B728a. Thus, the Hrp type III secretion system, but not HrpZ, plays an important role in enabling Pss to f lourish in the phyllosphere, but not the spermosphere. The hrcC and hrpJ mutants caused brown spot lesions on primary leaves at a low frequency when they were inoculated onto seeds at the time of planting. Pathogenic reactions also were found when the hrp secretion mutants were co-infiltrated into bean leaves with a non-lesion-forming gacS mutant of B728a. In both cases, the occurrence of disease was associated with elevated population sizes of the hrp secretion mutants. The role of the Hrp type III secretion system in pathogenicity appears to be largely mediated by its requirement for growth of Pss in the phyllosphere. Without growth, disease does not occur.

show abstract

Epiphytic Survival of Pseudomonas syringae on Hairy Vetch in Relation to Epidemiology of Bacterial Brown Spot of Bean in Wisconsin

Cited by 72 publications

References 12 publications

The distribution of some fungal and bacterial endophytes in maize (Zea mays L.)

The distribution of some fungal and bacterial endophytes in maize (Zea mays L.)

Bacterial Ice Nucleation: A Factor in Frost Injury to Plants

Role of the Hrp type III protein secretion system in growth of Pseudomonas syringae pv. syringae B728a on host plants in the field

Contact Info

Product

Resources

About