No political interference in US agricultural grants

I write on behalf of several former chief scientists in charge of the US Department of Agriculture’s National Research Initiative (NRI) competitive grants program. We wish to clarify part of your Editorial “A chance for growth” (Nature 432, 257; 2004). The Editorial could be interpreted as suggesting that the department’s competitive peer-reviewed research programs are influenced by political interests. Such interests have played a part in dictating the general areas in which to conduct research, but as chief scientists in the competitive programs area, we did not observe interference with the peer-review process itself

Book Review: GENETICALLY ENGINEERED ORGANISMS: BENEFITS AND RISKS

In the continuing debate on the introduction into the environment of genetically modified organisms, particularly those modified by recombinant DNA, there are few books suitably written for policymakers, the lay public and scientists in other fields. This book describes the current state of the science and art of genetic engineering, potential uses (particularly outside the laboratory), and the benefits that can be expected. It is particularly pertinent for examining potential risk and management of risk from the perspective of the United Kingdom

THE PLANT PATHOGENIC CORYNEBACTERIA

The plant pathogenic corynebacteria are a fascinating group of bacteria that produce effects as diverse as any in the microbial world, ranging from wilts to abnormal growths. Several new pathogens have been discovered since this group was reviewed by Jensen (75), Starr (157), and Lelliott (96). Most subsequent reviews have dealt with taxonomy. The areas covered in this review necessarily reflect my biases and limitations. However, this review attempts to be comprehensive in some areas, and it calls attention to other areas that would benefit from more detailed investigation

Synthetic and Complex Media for the Rapid Detection of Fluorescence of Phytopathogenic Pseudomonads: Effect of the Carbon Source

Fluorescence is of diagnostic value for differentiating among species of aerobic pseudomonads (R. Y. Stanier, N. J. Palleroni, and M. Doudoroff, J. Gen. Microbiol. 43:159, 1966). The standard medium for detecting fluorescence is Medium B (E. 0. King, M. K. Ward, and D. E. Raney, J. Lab. Clin. Med. 44:301, 1954), which supports fluorescent pigment production of most pseudomonads tested (0. Jessen, Pseudomonas aeruginosa and other green fluorescent pseudomonads, A taxonomic study, Munksgaard, Copenhagen, 1965; R. Y. Stanier et al., J. Gen. Microbiol. 43:159, 1966). Minerals (J. V. King, J. J. R. Campbell, and B. A. Eagles, Can. J. Res. C 26:514, 1948), amino acids (J. De Ley, Ann. Rev. Microbiol. 18:17, 1964), and peptones (E. 0. King et al., J. Lab. Clin. Med. 44:301, 1954) affect fluorescence. The effect of carbon sources had not been shown. Although glycerol, glucose, or maltose can be used interchangeably in Medium B for detecting fluorescence of most fluorescent pseudomonads, this report shows that these carbon sources are not equivalent for phytopathogenic pseudomonads

Public Policy on the Introduction of Genetically Engineered Microorganisms

This presentation raises questions of research needs and issues. Underlying assumptions are that only beneficial or useful microorganisms will be released ; that extensive laboratory and contained experiments will have been done prior to introduction and live microorganisms can be confined within the areas of introduction. Evidence to support these assertions will be presented. Critical needs for progress in this area include: 1) Recognition that the nature of the product introduced into the environment is of primary significance, not how the organism was genetically altered or modified. 2) Recognition that microorganisms are introduced into the environment as part of our daily lives. 3) Classification of microorganisms into categories, include a GRACE (Generally Regarded as Compatible with the Environment) list. For example, most microorganisms used by humans in food and agriculture would be on such a list. 4) Categorization of new traits transferred to microorganisms: all are not equal. 5) Revision of the Plant Pest Act. Interpretation by the USDA is now so broad that almost any microorganisms may be a plant pest . 6) Development of the means to enable continuation of basic research in small-scale traditional tests with GEMs. 7) Recognition of the adequacy of the methods used for mitigation and decontamination of microorganisms. 8) Development and use of selective, narrow spectrum chemicals and biologicals. 9) Critical evaluation of appropriate regulations and attendant costs for research on GEMs in the environment. These issues need recognition and wide-spread support among scientists, policy-makers and the public if the potential uses for microorganisms in the environment are to be realized

\u3ci\u3eCorynebacterium nebraskense\u3c/i\u3e, a New, Orange-Pigmented Phytopathogenic Species

A new species of Corynebacterium isolated from field corn is described. The isolates form a homogeneous group that is recognized as a new species, Corynebacterium nebraskense. The organism is characterized by orange-pig-mented colonies, inability to grow on 0.005% triphenyltetrazolium chloride agar, specific bacteriophage sensitivity, and a guanine plus cytosine content of 73.5 mol%. These and other characters differentiate this organism from other described phytopathogenic corynebacteria. The type strain of C. nebraskense is Fur-1 (= ATCC 27822 = NCPPB 2578)

Differential Effects of Lithium Chloride on In Vitro Growth of \u3ci\u3eClavibacter michiganense\u3c/i\u3e subsp. \u3ci\u3enebraskense\u3c/i\u3e Depending upon Inoculum Source

The bacterium Clavibacter michiganense subsp. nebraskense (Corynebacterium michiganense subsp. nebraskense) was grown in broth cultures and inoculated into corn plants. The plating efficiency of cells from broth cultures was essentially the same on nutrient broth-yeast extract and the semiselective medium for this bacterium, CNS. However, when cells were isolated from Goss bacterial wilt- and blight-infected corn, very few were recovered on CNS compared with the amount recovered on nutrient broth-yeast extract agar. When lithium chloride was omitted from the CNS, recoveries from infected corn were nearly the same as on nutrient broth-yeast extract agar. No other ingredient of CNS was inhibitory, nor did substitution of other salts for lithium chloride cause equal inhibition. The amount of inhibition was proportional to lithium chloride concentration. The inhibition by lithium chloride occurred with several strains of the bacterium isolated from one corn cultivar and with one of the strains recovered from three different cultivars of infected cor

Nitrogen Fixation (Acetylene Reduction) Associated with Roots of Winter Wheat and Sorghum in Nebraska

Root segments and root-soil cores (6.5-cm diameter) from fields and nurseries of winter wheat and sorghum were tested for N2 fixation by using the acetylene reduction assay. Wheat samples (~1,200) from 109 sites generally had low or no activity (0 to 3.1 nmol of C2H4 produced per h per g [dry weight] of root segments), even after 24 h of incubation. However, a commercial field of Scout 66, located in western Nebraska, exhibited appreciable activity (290 nmol of C2H4 produced per h per g [dry weight] of root segments). Of 400 sorghum lines and crosses, grain sorghums (i.e., CK-60A, Wheatland A, B517, and NP-16) generally exhibited higher nitrogenase activity than forage sorghums or winter wheats. CK-60A, a male sterile grain sorghum, was sampled at four locations and had the most consistent activity of 24 to 1,100 nmol of C2H4 produced per h per core. The maximum rate extrapolated to 2.5 g of N per hectare per day. Numerous N2-fixing bacterial isolates were obtained from wheat and sorghum roots that exhibited high nitrogenase activity. Most isolates were members of the Enterobacteriacae, i.e., Klebsiella pneumoniae, Enterobacter cloacae, and Erwinia herbicola

An Evolutionary Perspective of Pierce’s Disease of Grapevine, Citrus Variegated Chlorosis, and Mulberry Leaf Scorch Diseases

Xylella fastidiosa causes diseases on a growing list of economically important plants. An understanding of how xylellae diseases originated and evolved is important for disease prevention and management. In this study, we evaluated the phylogenetic relationships of X. fastidiosa strains from citrus, grapevine, and mulberry through the analyses of random amplified polymorphic DNAs (RAPDs) and conserved 16S rDNA genes. RAPD analysis emphasized the vigorous genome-wide divergence of X. fastidiosa and detected three clonal groups of strains that cause Pierce’s disease (PD) of grapevine, citrus variegated chlorosis (CVC), and mulberry leaf scorch (MLS). Analysis of 16S rDNA sequences also identified the PD and CVC groups, but with a less stable evolutionary tree. MLS strains were included in the PD group by the 16S rDNA analysis. The Asiatic origins of the major commercial grape and citrus cultivars suggest the recent evolution of both PD and CVC disease in North and South America, respectively, since X. fastidiosa is a New World organism. In order to prevent the development of new diseases caused by X. fastidiosa, it is important to understand the diversity of X. fastidiosa strains, how strains of X. fastidiosa select their hosts, and their ecological roles in the native vegetation