A total of 22 strains of a yellow-pigmented bacterium which I designated YB, which were isolated from leaves of various plants, were compared with the type strains of , and and six strains of , a pathogen of soybeans and garden beans. These species comprise the genus YB was nonpathogenic when it was inoculated onto leaves of soybeans and garden beans and produced β-carotene, as did both and These species and YB were all originally isolated from plants. YB could be distinguished from all previously described species of the genus on the basis of more rapid production of acid from maltose and xylose, more rapid hydrolysis of gelatin, susceptibility to bacteriophage PYB-3 infection, inability to hydrolyze hippurate, growth in the presence of 10% sodium chloride, and higher deoxyribonucleic acid guanine-plus-cytosine content. Because the YB strains represent a new center of variation in the genus , a new species, , is proposed. This bacterium was isolated from leaves of three soybean cultivars at weekly intervals. Mean populations, expressed in colony-forming units (CFU) per gram of leaf tissue, increased gradually over the season from 28 CFU/g at 5 weeks after planting to 158 CFU/g at plant maturity. The bacterium was also isolated from leaves of 10 soybean cultivars and 10 corn inbred lines in each of 3 years, from leaves in one soybean field and one corn field in each of 25 Iowa counties, and from leaves of each of 100 soybean plants from one field and 100 corn plants from one field. Over a 2-year period, it was isolated from all 200 plant species sampled. The samples represented 62 plant families and included trees (both broad leaved, and conifers), shrubs, annuals, and perennials. The bacterium was isolated from field-grown immature and mature soybean seeds and from leaves of soybean and corn seedlings grown in a microbe-free environment from seeds treated to eliminate external microorganisms. I concluded that is seed transmitted in soybeans and corn and is ubiquitous in the leaves of plants.


Article metrics loading...

Loading full text...

Full text loading...


Most cited this month Most Cited RSS feed

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error