Occurrence and distribution of sugarcane yellows phytoplasma and sugarcane yellow leaf virus in Mauritius
| MSI00P3400 | |
| Aljanabi, S. M. Parmessur, Y. Moutia, Y. Saumtally, S. Dookun, A. | |
| Occurrence and distribution of sugarcane yellows phytoplasma and sugarcane yellow leaf virus in Mauritius | |
| 6th ISSCT Sugarcane Pathology Workshop, Thailand, July 16-23, 2000 | |
| Conference paper | |
| 2000 | |
| Sugarcane in several parts of the world including the African continent and surrounding countries are currently affected by yellow leaf syndrome (YLS), which causes a yellowing of the crop before it reaches maturity. This yellowing is transmitted through vegetative propagation suggesting that it is caused by a pathogen. A luteovirus, sugarcane yellow leaf virus (ScYLV) has been associated with the syndrome. The association of a phytoplasma, sugarcane yellows phytoplasma (ScYP), with the disease has also been established in South Africa. Molecular techniques were optimized for the detection of the two pathogens in Mauritian commercial varieties and imported clones in quarantine. Polymerase chain reaction (PCR) and reverse transcriptase-PCR (RT-PCR) were used to detect ScYP and ScYLV. To detect the presence of the phytoplasma, primers P6 (5' CGG TAG GGA TAC CTT GTT ACG ACT TA) and SN910601 (5' GTT TGA TCC TGG CTC AGG ATT 3') were used for the general amplification of the 16S rDNA. For amplification of an internal fragment of the 16S rDNA of ScYP, primers R16F2n (5' GAA ACG ACT GCT AAG ACT GG 3') and R16R2 (5' TGA CGG GCG GTG TGT ACA AAC CCC G 3') were used. A 1.25 kb DNA fragment encoding for the 16S rRNA was consistently amplified by nested PCR. PCR product was digested separately with two restriction enzymes RsaI and HaeIII and restriction fragment length polymorphism patterns observed indicated that the phytoplasma present belonged to group sugarcane yellows phytoplasma I (ScYP I). The phytoplasma was detected in 63 (43.4 per cent) varieties obtained from quarantine, germplasm collection plots and major commercial fields around the island. Both the phytoplasma and ScYLV were detected in symptomatic as well in asymptomatic varieties. Typical YLS symptoms were observed in 79 (54.5 per cent) of the 145 samples tested and of these 77.8per cent were found infected with the phytoplasma while 54 per cent with ScYLV. Fifty-two (35.9 per cent) samples were co-infected with both pathogens. Of the 66 (45.5per cent) samples with no symptoms only 11 (16.6per cent) were free from both pathogens. There was a significant correlation (r=0.36, P=0.01) between the presence of the phytoplasma and YLS symptoms. A non-significant correlation (r= 0.09) was found between the presence of the ScYLV and symptoms using RT-PCR. These results strongly suggested that sugarcane YLS in Mauritius is significantly associated with ScYP rather than | |
| 01-08-2000 | |
| En | |
| Mauritius Sugar Industry Research Institute, Réduit, Mauritius | |
| Path Biotech |