Epiphytic survival of Pseudomonas viridiflava on tomato and selected weed species

Abstract

A rifampicin-nalidixic acid mutant of Pseudomonas viridiflava (PV) was studied in the field and greenhouse with respect to its epiphytic survival on the roots and foliage of a susceptible (FM 6203) and resistant (Ontario 7710) tomato cultivar and 16 weed species. In the field, populations varied between years, which was attributed to differences in environmental conditions. Hot, dry conditions caused rapid decline or elimination of populations. Some hosts were more conducive than others in promoting epiphytic growth, and generally, roots were better survival sites than foliage. Some hosts such as johnsongrass, lambsquarters, pigweed, prickly sida, and red sorrel had no detectable populations of PV on foliage 2 weeks after inoculation. (Plants had been misted with a 10(8) cfu/ml suspension until run off occurred.) PV was recovered at week 4 on the foliage of the two tomato cultivars, beggarweed, jimsonweed, morning glory, smooth vetch, and wild mustard, and was recovered until week 16 on roots of buckhorn plantain in the field and for the same period on the ground cherry in the field and greenhouse. In scanning electron microscopy studies, PV was observed to survive as microcolonies in depressions between epidermal cells, around trichomes, along veins, and sometimes around stomates of tomato and beggarweed. Bacterial cells sometimes were held together and to the leaf surface by fibril-like strands. These studies show that PV does have an epiphytic stage on both tomato and certain weed species. However, the epidemiological significance of the epiphytic stage is probably dependent on environmental conditions.

Responses of Phyllosphere Microbial Population of Some Common Road Trees In Relation To Dust Deposition – A Case Study in Kolkata, India

“…Theabaxial surface of leaf generally consist more number of trichrome, stomata [31].Even another colonizing microbes, bacteria tends to colonize at the lower surface of bacteria, near the stomata and trichrome. This observation was supported by a group of researchers [32][33]. The large flux of UV radiation, water and nutrient availability were the major factors for microbial growth in phylloplane.…”

The biology of Canadian weeds. 130. Amaranthus retroflexus L., A. powellii S. Watson and A. hybridus L.

“…Amaranthus retroflexus in North America is a host of the following pathogenic bacteria: Clavibacter michiganensis (Smith) Davis ssp. michiganensis: Illinois (Chang et al 1992); Pseudomonas viridiflava (Burkholder) Dowson: Georgia (Mariano and McCarter 1993); Xanthomonas phaseoli (ex Smith) Gabriel: Michigan (Cafati and Saettler 1980 For personal use only.…”

The biology of Canadian weeds. 8. Sinapis arvensis. L. (updated)

“…(b) Bacteria -Pseudomonas viridiflava (Burkholder) Dowson, which causes disease in a variety of plant species including tomato, can survive epiphytically for various periods on foliage and roots of S. arvensis (Mariano and McCarter 1993). S. arvensis is also a host for Spiroplasma citri Saglio, a pathogen causing brittle root disease of horseradish (Armoracia rusticana Gaertn., Mey., & Sherb.)…”