Identification and Characterization of the Causal Organism of Gummy Stem Blight in the Muskmelon (Cucumis meloL.)

Abstract

Gummy stem blight is a major foliar disease of muskmelon (Cucumis melo L.). In this study, morphological characteristics and rDNA internal transcribed spacer (ITS) sequences were analyzed to identify the causal organism of this disease. Morphological examination of the Jeonbuk isolate revealed that the percentage of monoseptal conidia ranged from 0% to 10%, and the average length × width of the conidia was 70 (± 0.96) × 32.0 (± 0.15) µm on potato dextrose agar. The BLAST analysis showed nucleotide gaps of 1/494, 2/492, and 1/478 with identities of 485/492 (98%), 492/494 (99%), 491/494 (99%), and 476/478 (99%). The similarity in sequence identity between the rDNA ITS region of the Jeonbuk isolate and other Didymella bryoniae from BLAST searches of GenBank was 100% and was 95.0% within the group. Nucleotide sequences of the rDNA ITS region from pure culture ranged from 98.2% to 99.8%. Phylogenetic analysis with related species of D. bryoniae revealed that D. bryoniae is a monophyletic group distinguishable from other Didymella spp., including Ascochyta pinodes, Mycosphaerella pinodes, M. zeae-maydis, D. pinodes, D. applanata, D. exigua, D. rabiei, D. lentis, D. fabae, and D. vitalbina. Phylogenetic analysis, based on rDNA ITS sequence, clearly distinguished D. bryoniae and Didymella spp. from the 10 other species studied. This study identified the Jeonbuk isolate to be D. bryoniae.

Identification and Characterization of the Causal Agent of Gummy Stem Blight from Muskmelon and Watermelon in East China

“…Based on the morphology of the isolates on PDA as well as the conidia, the isolates were identified as D. bryoniae. The data correlate with the earlier reports on the morphology of the D. bryoniae (Keinath et al 1995;Choi et al 2010).…”

Fusarium incarnatum is associated with postharvest fruit rot of muskmelon (Cucumis melo)

“…All growth stages of muskmelon are threatened by pathogens. For example, gummy stem blight caused by Didymella bryoniae is a major foliar disease of muskmelon in the seedling stage (Choi, Choi, Choi, Sharma, & Lee, ; Sudisha, Vasanth Kumar, Niranjana, & Shekar Shetty, ). In addition, Bacillus pumilus causes fruit rot (Song et al, ), and Penicillium oxalicum causes blue mould of muskmelon (Pornsuriya & Chitphithak, ).…”

Deteksi Gen Ketahanan Terhadap Gsb-4 (Gummy Stem Blight) pada Tanaman Melon (Cucumis Melo L.)

“…Sacc. (Wolukau et al, 2009;Choi et al, 2010). Gejala awal tanaman yang terserang patogen ini adalah luka sayatan yang menyebabkan buah, sulur atau akar lateral terpotong.…”