اولین گزارش بیماری لکه برگی نخل خرما ناشی از Nigrospora lacticolonia در خوزستان

Date palm (Phoenix dactylifera L.) is one of the most important sources of income for many farmers in Khuzestan province, with an area under cultivation about 40.000 hectares, and about 200.000 tons crops per year. Leaf spot is one of the important fungal diseases of date palm, which severely reduces the yield of the product. The purpose of this study was to identify the fungi that cause leaf spot disease in the groves of Khuzestan province, which is the first key step in disease management and control. Infected date palms were observed in date growing areas of Abadan,, Khoramshahr, Shadegan, Ahwaz and Hoveyze rejoins in Khuzestan province. After collection the infected leaves samples and transferring them to the laboratory with 90% alcohol, they were disinfected and cultured on Potato-dextrose-agar (PDA). Then after one-week, to 10 days, fungal isolates appeared, which purification by single spore and tip of hyphae methods were kept in refrigerator temperature (4◦C) for molecular investigation. The pathogenicity test was carried out on the leaves of the date palm of the Barhi variety prepared from the Palm and Tropical Fruits Research Institute. The isolates were identified using morphological and molecular characteristics. The translation elongation factor regions (tef) and and β-tubulin regions were amplified and sequenced by polymerase chain reaction (PCR). Mophological, characteristics, phylogenetic relationship and pathogenicity test determined that fungi Nigrospora lacticolonia is one of the causes of date palm leaf spot disease, which is reported for the first time from date palm in Khuzestan province.

Key words: Nigrospora lacticolonia, tef, β-tubulin, Leaf spot, PCR, isolates, phylogeny