Article Figures & Data
Figures
- Figure 1.
DAPI test for MLO detection. A longitudinal section of white ash rootlet was treated with DAPI (4’,6-diamidino-2-phenylindole·2HCI) and observed by means of fluorescence microscopy. Brightly fluorescing objects (n) are plant nuclei. Xylem (x) and phloem fibers (pp) are autofluorescing. DNA of MLOs in phloem sieve tubes appears as fluorescent speckles. Sieve tubes, which lack nuclei when mature, are otherwise invisible. Bar = 50 μm.
- Figure 2.
MLO differentiation by restriction enzyme analysis. A segment, approximately 1200 base pairs (BP) long, of the 16S ribosomal RNA gene of each of several MLO strains was amplified by polymerase chain reaction (PCR). PCR products were digested with restriction enzyme Kpnl and subjected to electrophoresis in an agarose gel, then were stained with ethidium bromide and photographed under UV illumination. The amplified DNA segment from eight of the MLO strains was not cut by this enzyme, so a single band of DNA from each of these strains is visible in the gel. MLO strains belonging to the aster yellows cluster (GD1, AY1, and BB) have two recognition sites for KprΛ in the amplified DNA segment, resulting in three fragments after digestion and distinguishing these MLOs from the others tested. MLO designations: AshY-ash yellows, AY-aster yellows, BB-tomato bigbud, EY-elm yellows, GD-dogwood stunt, GR-goldenrod yellows, LWB-lilac witches’-broom, MW-milkweed yellows. “Healthy” refers to DNA from healthy periwinkle (no PCR product obtained). Outside lanes are molecular size standards.
Tables
- Table 1.
Differentiation and classification of mycoplasmalike organisms on the basis of DNA sequence analysisa
Disease Occurrence Classification based on References 16S rDNA homology MLO strain cluster ot Lee & Davis etal(81) Lee et al(63) Schneider et al(91) Namba (58) Aster yellows Europe, N. America I I I Aster yellows 58, 59, 63, 91 Apricot chlorotic leaf roll (in periwinkle) Spain I(T) II Aster yellows 91, D. Gundersen, pers. comm. Bigbud and stolbur of nightshade, pepper, tomato Australia, Equador, Europe, USA I I Aster yellows 58, 59, 63, 91 Blueberry stunt Michigan I 63 Chrysanthemum yellows Italy I Aster yellows 4, 59, 63 Dogwood stunt (of gray dogwood) USA I Aster yellows 32 Grapevine yellows Italy I Aster yellows 16, 87 Molière’s disease of cherry France I 91 Mulberry dwarf China, Japan, Korea I 81 Onion yellows Japan I 81 Paulownia witches’-broom China, Japan, Taiwan I I Aster yellows 58, 63, 81 Peach decline Italy I 91 Periwinkle little leaf USA I Aster yellows 58,63 Phyllody of clover, Europe, Israel, I I Aster yellows 59, 63, 91 hydrangea, safflower North America Plum leptonecrosis (in periwinkle) Italy II 91 Sandal spike India I 91 Tomato yellows Japan I 81 Virescence of columbine, Diplotaxis, evening primrose, hydrangea, larkspur, periwinkle, Plantago, primrose, rape Germany, Peru, Thailand, USA I 3, 4, 91 Peanut witches’-broom Taiwan II 63 Red bird cactus witches’-broom Taiwan II 63 Sweet potato witches’-broom Taiwan II (T) 63, D. Gundersen, pers. comm. Almond brown line California III (T) 111 Blueberry witches’-broom Germany VI 91 Clover yellow edge Canada III Peach X disease 62, 63 Flavescence dorée of grapevine Italy, USA III VI Peach X disease 87, 91 Goldenrod yellows Eastern USA III Peach X disease 32 Milkweed yellows Canada, USA III Peach-X disease 32 Peach yellows North America Peach X disease 48 Pear decline California III (T) Lee et al(unpub) Spirea stunt New York State III Peach X disease 32 X-diseases of cherry, peach, prune North America III VI Peach X disease 48, 58, 62, 63, 91 Tsuwabuki witches’-broom Japan in (T) II 81, D. Gundersen, pers. comm. Walnut witches’-broom Eastern USA HI (T) Peach X disease 48 Pecan bunch Eastern USA HI (T) Peach X disease 48 Lethal yellowing of palms Caribbean basin IV 63 Alder decline Europe IV Elm yellows 74, 91 Elm yellows, elm witches’-broom Europe, North America V IV Elm yellows 58, 61,63, 74, 91 Flavescence dorée of grapevine France V Elm yellows 87 Rubus stunt Germany IV 91 Clover proliferation Canada VI Clover proliferation 23, 58, 63 Potato witches’-broom Canada VI Clover proliferation 23, 58, 63 Tomato bigbud, virescence of periwinkle Western USA VI 58, 99 Ash yellows, lilac witches’-broom North America VII III Ash yellows 20, 32, 39, 63, 91 Loofah witches’-broom Taiwan VIII 63 Pigeon pea witches’-broom Florida IX 63 Apple proliferation Europe X V 63, 91 Apricot chlorotic leafroll Italy X 57 Decline of apricot, Germany V 91 flowering cherry, peach Pear decline Italy X 57 Plum leptonecrosis Italy X (T) 57 Rice yellow dwarf Asia XI (T) III Rice yellow dwarf 79, 81, D.Gundersen, pers. comm. Bermudagrass whiteleaf Asia VII 91 Sugarcane whiteleaf Asia VII 91 Unclassified Apricot proliferation USA 48 Black locust witches’-broom USA, Italy 93, 98 Chestnut yellows Japan 84, 97 Decline of European aspen and hawthorn Europe 94 Dogwood witches’-broom Eastern USA 90 Elder decline Germany 55 Jujube witches’-broom China, Korea 80 Lime witches’-broom Persian Gulf region 29 Oak decline Europe 30, E. Seemüller, pers. comm. Peach rosette USA 97 Pear decline California, Eastern USA, Great Britain 15, 49, 77, 95 Plum proliferation, prune decline California 48 Salix yellows (willow witches’-broom) Italy, USA 32, 42, 93 ↵a Assignments to groups and clusters are based primarily on schemes proposed by Lee and Davis (58), Lee et al. (63), and Schneider et al. (91). MLO group numbers in these schemes do not coincide. Tentative assignments are the authors’ interpretations. Many unclassified MLOs known in Asia are omitted. Dashed lines separate MLO groups and clusters that are likely to remain together as classification research continues. Some disease names appear in more than one category, because diverse MLOs have been found associated with them.
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