மூலக்கூறு மற்றும் மரபணு மருத்துவம்

First Report of Northern Corn Leaf Blight Disease Caused by Exserohilum turcicum on Zea mays in Malaysia

Abstract

Bashir KA, Kamaruzaman S and Khairulmazmi A

In April 2015, Northern corn leaf blight (NCLB) symptoms were observed in corn plants (Zea mays L.) in cold highland areas at Titi Gantong, Lembah Bertam farms, Malaysia. The typical symptom of NCLB disease showed abundant lesions on the leaves of susceptible cultivars (5-20 cm long), greyish to tan in colour and elliptical in shape. Exserohilum turcicum (Pass.) was isolated from diseased leaf and cultured on PDA media for further morphological investigation. The colonies of E. turcicum on PDA are dark grey in colour and grow faster. Conidial shapes were straight to slightly curved, the hilum protrudes as a truncate at the base of the conidia. Conidial colour was pale to olivaceous brown, while the conidial size ranged from 56 to 89 μm in length, 9 to 13 μm in width, and the number of septa ranged from 6-10. Conidia were 4-9 distosptate, with a thicker wall at the base of each conidium. Based on description reported by Sivanesan (1987) the isolate was identified as E. turcicum. To verify the morphological findings, PCR amplification was conducted using universal primers, TUBUF2 forward (5' CGGTAACAACTGGGCCAAGG-3') and TUBUR1 reverse (5'-CCTGGTACTGCTGGTACTCAG-3') and yielded a 1000-bp product. Blast result showed that the sequence was having 97% similarity to published sequence of Setosphaeria turcica, teleomorph of E. turcicum (Accession No. XM_008032318). To our belief and knowledge, this is the first report of E. turcicum as the causative agent of NCLB disease of corn in Malaysia. There is need for future studies to focus on assessing management options for this disease to avoid corn yield losses in Malaysia.