Dna extraction and storage methods have been evaluated with laboratoryreared leafhoppers andor fieldcollected leafhoppers and psyllids. A unique virulence factor for proliferation and dwarfism. The speediest of these bacteria, mycoplasma mobile, can move at speeds of up to 4 mms. Effect of polyclonal, monoclonal, and recombinant single. The results indicate the presence of two sets of ribosomal genes in all strains examined. Candidatus phytoplasma palmae lethal yellowing of coconut. New perspectives on phytopathogenic mollicutes phytoplasma identity and disease etiology r. Phylogenetic positions of candidatus phytoplasma asteris and spiroplasma kunkelii. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext. Their propulsive organelle is located in a protrusion that projects from the anterior of the cell miyata and uenoyama, 2002. Phytoplasmas are uncultured wallless bacteria class mollicutes that live in the phloem of their host plants and are transmitted by insect vectors belonging to the order homoptera. The record is currently held by a phytopathogenic bermudagrass phytoplasma at 530 kb. In large part, this progress has resulted from the development and use of molecular methods to detect.
She is the author of 800 publications, editorinchief of phytopathogenic mollicutes, senior editor of phytopathologia mediterranea, and founded and heads the international phytoplasmologist working group ipwg. The pigeon pea witchesbroom phytoplasma group 16srix comprises diverse strains that cause numerous diseases in leguminous trees and herbaceous crops, vegetables, a fruit, a nut tree and a forest tree. Interestingly, french researcher chastel 1987 found a total of 23 spiroplasma strains isolated from four species of mosquitoes. Pdf phylogenetic classification of phytopathogenic. Lethal yellowing and related diseases pose a significant threat to global coconut production harries, 1978b. This book will be useful to everyone interested in mollicutes, phytoplasma, spiroplasmas, plant pathology, disease control and plant biology and serve as an exhaustive and uptodate compendium of references on various aspects of different groups of phytoplasmas affecting important crops worldwide. Phytopathogenic mollicutes, which include spiroplasmas and phytoplasmas, are cell wallless.
In case of print copy, the member will also have to bear the postage of journal. Bacterial colonies on a nutrient medium acilliform bacterium. Extensive phylogenetic analyses were performed based on sequences of the 16s rrna gene and two ribosomal protein rp genes, rplv rpl22 and rpsc rps3, from 46 phytoplasma strains representing 12 phytoplasma 16sr groups, 16 other mollicutes and 28 grampositive walled bacteria. Mollicutes is a class of bacteria distinguished by the absence of a cell wall. Differentiation and classification of phytoplasmas in the. The journal publishes papers that describe translational and applied research focusing on practical aspects of disease diagnosis, development, and management in agricultural and horticultural crops.
The following is a general classification agrios, 5th ed, 2005 of phytopathogenic prokaryotes with the exception of the division tenericutes, class mollicutes, which will be addressed in a later section. Comparative phylogenetic analyses of the highly conserved 16s rrna gene and the moderately conserved rplv rpl22rpsc rps3 and secy. The abstract book of the meeting is published in the phytopathogenic mollicutes volume 9, number 1 june 2019 issue and it can be downloaded as. Detection of four different phytopathogenic phytoplasmas, belonging to three taxonomic groups, has been achieved by several direct or nested polymerase chain reaction pcr methods with such dna extracts. Phytoplasmas basically survive in phloem tissues of plants and produce symptoms like yellowing, phyllody and witches brooms. Phytoplasmas are wallless prokaryote which are phytopathogenic and belong to class mollicutes. This is why expression of antibodies in plants is an attractive strategy to control phytopathogenic mollicutes, especially since at this time, there is no other curative method. Presence of two sets of ribosomal genes in phytopathogenic. Spiroplasma and candidatus phytoplasma comprise two genera of insect. Ribosomal r rna interoperon sequence heterogeneity in the fragaria multicipita phytoplasma, a member of group 16srvi, was initially observed in rflp patterns of rdna amplified in the polymerase chain reaction pcr, and was confirmed through sequence analysis of cloned rdna. Thus mollicutes possibly became the smallest selfreplicating organism in nature. Phylogenetic positions of candidatus phytoplasma asteris.
Only recently, through the introduction ofmolecular methods into plant mycoplasmology, has it becomepossible to differentiate. Diversity, host range, and the impact of farming practices on disease incidence abstract the coconut palm cocos nucifera is a major cash crop that is widely grown in coastal tropical regions of the. The phylogenetic tree inferred from rp genes had a similar overall topology to that inferred from the 16s rrna gene. Nonhelical phytopathogenic mollicutes, usually known as mycoplasmalike organisms mlos, are a group of widely distributed, wallless prokaryotes that are associated with diseases of several hundred plant species 10, 11. Google scholar rasu t, rajendran r, lingan r, sundarasu s, gandhi k, sevugapperumal n, ramalingam r, ramasamy s 2011 first report of little leaf disease associated with phytoplasma on sugar beet beta vulgaris l. Internet conference on phytopathogenic mollicutes, invited lecture, spiroplasma taxonomy, 2001. The life cycles of plant pathogenic spiroplasmas and phytoplasmas are very similar, and the infection patterns of these organisms exhibit common characteristics. She has received numerous awards, including the emmy klienenbergernobel award for distinguished research in mycoplasmology. Many are able to move about through gliding, but members of the genus spiroplasma are helical and move by twisting.
Generally bacteria are saprophytic but few species are parasitic which can be found within or outside plant. Department of plant pathology, cornell university, ithaca, ny 148534203. Articles are characterized by their novelty, innovativeness, and the hypothesisdriven nature of their. The members of tsbas will receive free either print online copy or print copy of the phytopathogenic mollicutes.
During the past decade, research has yielded new knowledge about the plant and insect host ranges, geographical distribution, and phylogenetic relationships of phytoplasmas, and a taxonomic system has emerged in which distinct phytoplasmas are named as separate phytoplasma species. Phytopathogenic bacteria are causative infectious agents of plant diseases. They vary in form, although most have sterols that make the cell membrane somewhat more rigid. Molecular plant pathology laboratory, agricultural research serviceusda, beltsville, md 20705. Technology society of basic and applied sciences mollicutes. With the discovery of several groups of mycoplasma like organism, it has been categorised as mycoplasmas infect animals. They are transmitted by insects belonging to the families. The word phyto refers to plant and pathogenic bacteria, fungi, molds and viruses specific to plant species are responsible for induction of disease symptoms. Phytoplasma diseases of industrial crops springerlink.
The fact that mollicutes have the smallest known genomes has made this group a target for genomics projects. Coconut lethal yellowing phytoplasma disease in mozambique. A unique virulence factor for proliferation and dwarfism in plants identified from a phytopathogenic bacterium ayaka hoshia,1, kenro oshimaa,1, shigeyuki kakizawaa,1, yoshiko ishiia, johji ozekia, masayoshi hashimotoa, ken komatsua, satoshi kagiwadab, yasuyuki yamajia, and shigetou nambaa,2 adepartment of agricultural and environmental biology, graduate school of agricultural and life. Another class of mollicutes, the mycoplasmas, move by gliding over surfaces. To discourage inadvertant spread of ly in the tropics, commercial movement of living palms and palm seeds from affected to unaffected areas is generally not permitted. Plant disease is the leading international journal for rapid reporting of research on new, emerging, and established plant diseases. Sequences from operons rrna and rrnb were amplified in pcr primed by primer pair p1p7 but from only rrna in pcr. The phylogenetic relationships of 17 phytopathogenic mycoplasmalike organisms mlos representing seven major taxonomic groups established on the basis of mlo 16s ribosomal dna rdna restriction patterns were examined by performing a sequence. Mollicutes clade, suggesting that the genes encoding the. Differential amplification of sequence heterogeneous.
Presence of two ribosomal genes phytopathogenic mollicutes. Taxonomy based on 16s ribosomal gene, is it enough. The phytoplasmas are presently subdivided into 15 groups based on the similarity of their 16s ribosomal dna rdna sequences. The word mollicutes is derived from the latin mollis meaning soft or pliable, and cutis meaning skin. Perspectives for the management of phytoplasma diseases through genetic or induced resistance. These pathogenic bacteria are walled proteobacteria. Dna from 28 strains of phytopathogenic mycoplasmalike organisms that represented five primary taxonomic clusters was digested with restriction endonucleases and hybridized with several ribosomal probes. Increasing incidence of sugarcane grassy shoot disease in uttar pradesh, and its impact on yield and quality of sugarcane in india. In 1992, the subcommittee on the taxonomy of mollicutes proposed the use of phytoplasma rather than mycoplasmalike organisms for reference to the phytopathogenic mollicutes. Phytopathogenic mollicutes an international journal on phytoplasma, spiroplasma and other phloemlimited plant pathogens published by. Identification and molecular characterization of the. Phytopathogenic bacteria bacterial diseases in plants. In 2004, the generic name phytoplasma was adopted and is currently of candidatus ca.
842 1001 266 474 129 956 1327 1500 1073 1126 1021 656 1240 202 752 36 474 566 233 831 708 343 923 45 1088 808 1593 829 59 53 939 1485 467 10 826 754 1184 1411 518 208 303 523