Degradation of Nodulation Signals from Rhizobium meliloti by its Host Plants

1997 ◽  
pp. 43-46 ◽  
Author(s):  
Christian Staehelin ◽  
Maud Vanney ◽  
Fabrice Foucher ◽  
Eva Kondorosi ◽  
Michael Schultze ◽  
...  
Keyword(s):  
Host Plants ◽  
Rhizobium Meliloti

Nodulating competitiveness amongst strains of Rhizobium meliloti and R. trifolii

1974 ◽  
Vol 25 (2) ◽  
pp. 317 ◽  
Author(s):  
C Marques Pinto ◽  
PY Yao ◽  
JM Vincent
Keyword(s):  
Medicago Sativa ◽  
Trifolium Repens ◽  
Host Plants ◽  
Rhizobium Meliloti ◽  
Root Surface ◽  
Mixed Infections ◽  
Relative Speed ◽  
Nitrogen Fixing ◽  
Single Culture ◽  
The One

The relative nodulating success of strains of Rhizobium meliloti, with Medicago sativa and M. truncatula, and R. trifolii, with Trifolium repens, T. glomeratum and T. subterraneum, has been determined with inocula of paired competitors, supplied in various proportions. Host plants were raised from surface-sterilized seed, grown on agar in enclosed tubes, and populations and strain ratios were determined on the root surface as well as in the supplied inoculum. The use of heavy inoculum did not prevent all growth, and strain representation on the root surface could differ from that of the inoculum, because of either different adherence or the narrowing of extreme ratios with time. The ratios of strains obtained from nodules when related to those on the root surface yielded a 'competitive index', defined as the ratio of nodules due to each strain under conditions of equal representation on the root. In the five available cases inferior nitrogen-fixing effectiveness of a strain with a particular host was reflected in poor nodulating competitiveness, but similar differences were found in six comparisons between equally effective pairs, and with the one ineffective pair. Competitiveness did not correlate with the relative speed with which the strains produced nodules when used as a single culture or with the number of nodules they produced. Cases of mixed infections were encountered throughout the study; they generally accounted for less than 10% of the nodules typed, but in some combinations of host and strains the figure exceeded 25%.

scholarly journals Rhizobium meliloti genes involved in sulfate activation: the two copies of nodPQ and a new locus, saa.

Genetics ◽  
1992 ◽  
Vol 132 (4) ◽  
pp. 899-909 ◽  
Author(s):  
J S Schwedock ◽  
S R Long
Keyword(s):  
Host Plants ◽  
Rhizobium Meliloti ◽  
Atp Sulfurylase ◽  
Plant Host ◽  
Nod Factor ◽  
Aps Kinase ◽  
Specific Host ◽  
Cysteine Synthesis ◽  
Sulfate Activation ◽  
Leguminous Host

Abstract The nitrogen-fixing symbiont Rhizobium meliloti establishes nodules on leguminous host plants. Nodulation (nod) genes used for this process are located in a cluster on the pSym-a megaplasmid of R. meliloti. These genes include nodP and nodQ (here termed nodPQ), which encode ATP sulfurylase and APS kinase, enzymes that catalyze the conversion of ATP and SO(4)2- into the activated sulfate form 3'-phosphoadenosine 5'-phosphosulfate (PAPS), an intermediate in cysteine synthesis. In Rhizobium, PAPS is also a precursor for sulfated and N-acylated oligosaccharide Nod-factor signals that cause symbiotic responses on specific host plants such as alfalfa. We previously found a highly conserved second copy of nodPQ in R. meliloti. We report here the mapping and cloning of this second copy, and its location on the second megaplasmid, pSym-b. The function of nodP2Q2 is equivalent to that of nodP1Q1 in complementation tests of R. meliloti and Escherichia coli mutants in ATP sulfurylase and adenosine 5'-phosphosulfate (APS) kinase. Mutations in nodP2Q2 do not have as severe an effect on symbiosis or plant host range as do those in nodP1Q1, however, possibly reflecting differences in expression and/or channeling of metabolites to specific enzymes involved in sulfate transfer. Strains mutated or deleted for both copies of nodQ are severely defective in symbiotic phenotypes, but remain prototrophic. This suggests the existence in R. meliloti of a third locus for ATP sulfurylase and APS kinase activities. We have found a new locus saa (sulfur amino acid), which may also encode these activities.

Yellow Brazilian Pepper-tree Leaf Galler (suggested common name) Calophya latiforceps Burckhardt (Insecta: Hemiptera: Calophyidae: Calophyinae)

EDIS ◽  
2017 ◽  
Vol 2017 (6) ◽  
Author(s):  
James P. Cuda ◽  
Patricia Prade ◽  
Carey R. Minteer-Killian
Keyword(s):  
Biological Control ◽  
North America ◽  
Natural Enemies ◽  
Host Plants ◽  
Classical Biological Control ◽  
Biological Control Agents ◽  
Pepper Tree ◽  
Brazilian Pepper ◽  
Close Relatives ◽  
Tree Leaf

In the late 1970s, Brazilian peppertree, Schinus terebinthifolia Raddi (Sapindales: Anacardiaceae), was targeted for classical biological control in Florida because its invasive properties (see Host Plants) are consistent with escape from natural enemies (Williams 1954), and there are no native Schinus spp. in North America. The lack of native close relatives should minimize the risk of damage to non-target plants from introduced biological control agents (Pemberton 2000). [...]

SPECIES, HOST RANGE, AND IDENTIFICATION KEY OF WHITEFLIES OF BOGOR AND SURROUNDING AREA

2019 ◽  
Vol 18 (2) ◽  
pp. 127
Author(s):  
Purnama Hidayat ◽  
Denny Bintoro ◽  
Lia Nurulalia ◽  
Muhammad Basri
Keyword(s):  
Host Range ◽  
Host Plants ◽  
Ornamental Plants ◽  
Identification Key ◽  
Agricultural Crops ◽  
Surrounding Area ◽  
Aleurodicus Dispersus ◽  
Agricultural Plants ◽  
Surrounding Areas ◽  
Forest Plants

Species identification, host range, and identification key of whiteflies of Bogor and surrounding area. Whitefly (Hemiptera: Aleyrodidae) is a group of insects that are small, white, soft-bodied, and easily found on various agricultural crops. Whitefly is a phytophagous insect; some species are important pests in agricultural crops that can cause direct damage and can become vectors of viral diseases. The last few years the damage caused by whitefly in Indonesia has increased. Unfortunately, information about their species and host plants in Indonesia, including in Bogor, is still limited. Kalshoven, in his book entitled Pest of Crops in Indonesia, published in the 1980s reported that there were 9 species of whitefly in Indonesia. The information on the book should be reconfirmed. Therefore, this study was conducted to determine whitefly species and its host plants in Bogor and its surroundings. Whiteflies is identified based on the ‘puparia’ (the last instar of the nymph) collected from various agricultural plants, ornamental plants, weeds, and forest plants. A total of 35 species of whiteflies were collected from 74 species and 29 families of plants. The collwcted whiteflies consist of four species belong to Subfamily Aleurodicinae and 31 species of Subfamily Aleyrodinae. The most often found whitefly species were Aleurodicus dispersus, A. dugesii, and Bemisia tabaci. A dichotomous identification key of whiteflies was completed based on morphological character of 35 collected species. The number of whitefly species in Bogor and surrounding areas were far exceeded the number of species reported previously by Kalshoven from all regions in Indonesia.

TUNGAU PADA DAUN MANGGA (Mangifera Indica)

2014 ◽  
Vol 13 (3) ◽  
Author(s):  
Rawati Panjaitan
Keyword(s):  
Life Cycle ◽  
Direct Observation ◽  
Host Plants ◽  
Body Shape ◽  
Leaf Surface ◽  
Mangifera Indica ◽  
Posterior Part ◽  
Mango Leaves

Mites have hostplant specifications or host plants. Mites can be destructive and deadly of which is the host plants a mango crop. Mites on mango crops will cause the leaves yellow and fall off prematurely. This is will lead to the disruption of the productivity of mango. It is necessary for research to identify the mites that infect the mango crop. The method is carried out by direct observation. Mites were taken from the surface of mango leaves later in preservation with several levels of concentration of alcohol, and polyvinyl laktofenol. Then, observed under a microscope and documented for identification purposes. Mites on the leaf surface of manalagi mango (<em>Mangifera indica</em>) found two species, it is <em>Oligonychus</em> sp. and <em>Oligonychus ilicis</em> (Family: Tetranychidae, Superfamily: Tetranychoidea). <em>Oligonychus</em> sp. hallmark is rounded body shape like a spider, with a body is transparent and there are two long seta on posterior part. While <em>Oligonychus ilicis</em> has a characteristic elongated rounded body shape, red, and there is a short posterior seta. <em>Oligonychus</em> sp. and <em>Oligonychus ilicis</em> live as parasites on the surface of mango leaves that can lead to wrinkled leaves, yellow and to fall. <em>Oligonychus</em> life cycle starts from the eggs develop into Nympha and then adult.

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