Identification and characterization of phytoplasmal genes, employing a novel method of isolating phytoplasmal genomic DNA.
Phytoplasmas are unculturable, insect-transmissible plant pathogens belonging to the class Mollicutes. To be transmitted, the phytoplasmas replicate in the insect body and are delivered to the insect's salivary glands, from where they are injected into the recipient plant. Because phytoplasmas cannot be cultured, any attempt to recover phytoplasmal DNA from infected plants or insects has resulted in preparations with a large background of host DNA. Thus, studies of the phytoplasmal genome have been greatly hampered, and aside from the rRNA genes, only a few genes have hitherto been isolated and characterized. We developed a unique method to obtain host-free phytoplasmal genomic DNA from the insect vector's saliva, and we demonstrated the feasibility of this method by isolating and characterizing 78 new putative phytoplasmal open reading frames and their deduced proteins. Based on the newly accumulated information on phytoplasmal genes, preliminary characteristics of the phytoplasmal genome are discussed.
Melamed
Sharon
S
Institute for Plant Sciences, Faculty of Agricultural, Food and Environmental Quality Sciences, The Hebrew University of Jerusalem, Rehovot 76100, Israel.
Tanne
Edna
E
Ben-Haim
Raz
R
Edelbaum
Orit
O
Yogev
David
D
Sela
Ilan
I
D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics*; D001431:Bacteriological Techniques; D003001:Cloning, Molecular; D003062:Codon; D019295:Computational Biology; D004269:DNA, Bacterial / Q000032:analysis / Q000302:isolation & purification*; D016680:Genome, Bacterial; D006430:Hemiptera / Q000382:microbiology*; D007303:Insect Vectors / Q000382:microbiology*; D008969:Molecular Sequence Data; D016366:Open Reading Frames / Q000235:genetics; D010935:Plant Diseases / Q000382:microbiology; D012463:Saliva / Q000382:microbiology*; D017422:Sequence Analysis, DNA; D008973:Tenericutes / Q000235:genetics* / Q000302:isolation & purification
D001426:Bacterial Proteins; D003062:Codon; D004269:DNA, Bacterial