TY - JOUR
T1 - First report of a "Candidatus Phytoplasma australiense"
T2 - related strain in lucerne (Medicago sativa) in Australia
AU - Getachew, Mohammad Ali
AU - Mitchell, Andrew
AU - Gurr, Geoffrey
AU - Fletcher, Murray
AU - Pilkington, L.J.
AU - Nikandrow, Alex
AU - Elliot, Eric
N1 - Imported on 12 Apr 2017 - DigiTool details were: Journal title (773t) = Plant Disease: an international journal of applied plant pathology. ISSNs: 0191-2917;
PY - 2007
Y1 - 2007
N2 - investigation. 'Ca. P. asteris' and stolbur group (16SrXII) phytoplasmas have been reported in lucerne in the United States (2) and Italy (1), respectively. Within the stolbur group 16SrXII, 'Ca. P. australiense' and stolbur phytoplasma are regarded as separate species and both are distinct from 'Ca. P. asteris', a group 16SrI strain. To our knowledge, this is the first report of a 'Ca. P. australiense' related strain in lucerne.Australian lucerne yellows (ALuY), a phytoplasma-associated disease, is a major problem in Australia that causes the pasture seed industry millions of dollars in losses annually (3). Samples were collected from lucerne (Medicago sativa L.) plants exhibiting symptoms indicative of ALuY (4) in a seed lucerne paddock (cv CW 5558) at Griffith, southwestern New South Wales (NSW), Australia, in November 2005 and again in January 2006. Samples were kept at 4°C and processed within 36 h of collection. Total DNA was extracted from approximately 0.3 g of leaf midribs and petioles of each plant sample and used as template in a nested PCR assay with phytoplasma universal primer pairs P1/P7 and fU5/m23sr. PCR products resulting from the first amplification were diluted (1:30) with sterile distilled water (SDW) before reamplification with fU5/m23sr. DNA of Australian tomato big bud (TBB) phytoplasma and SDW were used as positive and negative assay controls, respectively. Ten of fifteen plant samples collected in November tested positive for phytoplasma DNA. Restriction digestion profiles of nested PCR amplicons with HpaII endonuclease were the same for all symptomatic plants but differed from the control. Phytoplasma identity was determined by sequencing two nested PCR products that yielded identical sequences. One was deposited in the GenBank database (Accession No. DQ786394). BLAST analysis of the latter sequence revealed a >99.6% similarity with 'Candidatus Phytoplasma australiense' (L76865) and related strains papaya dieback (Y10095), phormium yellow leaf (U43570), strawberry green petal (AJ243044), and strawberry lethal yellows (AJ243045). Direct PCR with primers FP 5'-GCATGTCGCGGTGAATAC-3' and RY 5'-TGAGCTATAGGCCCTTAATC-3' designed to specifically amplify DNA of 'Ca. P. australiense' detected the phytoplasma in 8 of 40 samples collected in January. Whether this phytoplasma is the etiological agent solely responsible for ALuY is currently under
AB - investigation. 'Ca. P. asteris' and stolbur group (16SrXII) phytoplasmas have been reported in lucerne in the United States (2) and Italy (1), respectively. Within the stolbur group 16SrXII, 'Ca. P. australiense' and stolbur phytoplasma are regarded as separate species and both are distinct from 'Ca. P. asteris', a group 16SrI strain. To our knowledge, this is the first report of a 'Ca. P. australiense' related strain in lucerne.Australian lucerne yellows (ALuY), a phytoplasma-associated disease, is a major problem in Australia that causes the pasture seed industry millions of dollars in losses annually (3). Samples were collected from lucerne (Medicago sativa L.) plants exhibiting symptoms indicative of ALuY (4) in a seed lucerne paddock (cv CW 5558) at Griffith, southwestern New South Wales (NSW), Australia, in November 2005 and again in January 2006. Samples were kept at 4°C and processed within 36 h of collection. Total DNA was extracted from approximately 0.3 g of leaf midribs and petioles of each plant sample and used as template in a nested PCR assay with phytoplasma universal primer pairs P1/P7 and fU5/m23sr. PCR products resulting from the first amplification were diluted (1:30) with sterile distilled water (SDW) before reamplification with fU5/m23sr. DNA of Australian tomato big bud (TBB) phytoplasma and SDW were used as positive and negative assay controls, respectively. Ten of fifteen plant samples collected in November tested positive for phytoplasma DNA. Restriction digestion profiles of nested PCR amplicons with HpaII endonuclease were the same for all symptomatic plants but differed from the control. Phytoplasma identity was determined by sequencing two nested PCR products that yielded identical sequences. One was deposited in the GenBank database (Accession No. DQ786394). BLAST analysis of the latter sequence revealed a >99.6% similarity with 'Candidatus Phytoplasma australiense' (L76865) and related strains papaya dieback (Y10095), phormium yellow leaf (U43570), strawberry green petal (AJ243044), and strawberry lethal yellows (AJ243045). Direct PCR with primers FP 5'-GCATGTCGCGGTGAATAC-3' and RY 5'-TGAGCTATAGGCCCTTAATC-3' designed to specifically amplify DNA of 'Ca. P. australiense' detected the phytoplasma in 8 of 40 samples collected in January. Whether this phytoplasma is the etiological agent solely responsible for ALuY is currently under
U2 - 10.1094/PD-91-0111A
DO - 10.1094/PD-91-0111A
M3 - Article
SN - 0191-2917
VL - 91
SP - 111
EP - 111
JO - Plant Disease
JF - Plant Disease
IS - 1
ER -