FUSARIUM FUJIKUROI ASSOCIATED WITH BAKANAE DISEASE OF RICE IN SOUTHERN LAO PDR.
Scherm, B.; Infantino, A.; Balmas, V.; Aragona, M.; Ireland, K.; Phantavong, S.; Phitsanoukane, P.; Vongvichid, K.; Burgess, L.
Book of Abstract 13th European Fusarium Seminar, Martina Franca (TA), Italy, 11-14 maggio 2015.
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Samples of rice plants, showing typical symptoms of bakanae disease were
collected in 2013 and 2014 from three provinces in southern Laos: Champasak;
Saravan and Savannakhet. Symptomatic plants were scattered but easy to detect
due to the abnormal stem elongation. However there were some stunted plants
with symptoms of stem base browning and necrosis. These were also collected.
The presence of white-violet mycelium was occasionally observed on the stem of
diseased plants. Up to 20 plants were collected from each sampling site. Isolations
were attempted by plating a 2 cm length including the 2nd node from one
symptomatic stem of each plant. Two hundred and seventeen colonies were
isolated. Monosporic cultures were grown on CLA and were morphologically
identified. Ninety five percent of the fungal isolates recovered were F. fujikuroi. A
total of 12 populations, ranging from 9 to 24, were selected. In order to confirm the
morphological identification, DNA was extracted from these isolates and a
species-specific PCR was conducted on each with primers Fuji1F (5’-
ACGTGTCAAACTAAACATTCGA-3’) and TEF1R (5’-GCGACAACATACCAATGACG-
3’). Mating type distribution within each population was assessed by PCR using
primer pairs M1C-5/M1C-13, and M2C-9/ M2C-4, specific for MAT-1 and for MAT-2
alleles, respectively. The results will be presented in the poster. The etiology of
bakanae disease in Laos has not been clearly defined to the best of our
knowledge although the has been reported. In this note we clearly demonstrate
that F. fujikuroi is the causative agent of bakanae in southern Laos. The disease is
not a serious problem in the Lao PDR and is mainly found in traditional varieties that
farmers prefer for home consumption. It is rarely seen in modern higher-yielding
rice varieties. Thus the situation in the Lao PDR differs from Italy where the disease is
causing concern in modern varieties.