Infection Biology of Stagonosporopsis cucurbitacearum in Watermelon and Defence Responses in the Host
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Infection Biology of Stagonosporopsis cucurbitacearum in Watermelon and Defence Responses in the Host. / Nga, Nguyen Thi Thu; de Neergaard, Eigil; Jørgensen, Hans Jørgen Lyngs.
In: Agriculture, Vol. 14, No. 3, 380, 2024.Research output: Contribution to journal › Journal article › Research › peer-review
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T1 - Infection Biology of Stagonosporopsis cucurbitacearum in Watermelon and Defence Responses in the Host
AU - Nga, Nguyen Thi Thu
AU - de Neergaard, Eigil
AU - Jørgensen, Hans Jørgen Lyngs
N1 - Publisher Copyright: © 2024 by the authors.
PY - 2024
Y1 - 2024
N2 - Infection biology and defence responses of watermelon attacked by Stagonosporopsis cucurbitacearum (syn. Didymella bryoniae) were studied in two genotypes, accessions PI189225 (moderately resistant) and 232-0125/B (susceptible). On intact leaf surfaces, spores started to germinate 14 h after inoculation (hai) with one to three germ tubes, which subsequently developed and formed appressoria. Invasion of the host tissue started at 20 hai by direct penetration from appressoria or occasionally indirectly through stomata. In the susceptible accession, a significantly higher number of direct penetrations were observed than in the moderately resistant. After invasion, hyphal colonisation was restricted in the intercellular spaces in the moderately resistant accession, whereas they developed extensively, causing tissue decay, in the susceptible accession. Macroscopic symptoms were seen in leaves of the moderately resistant accession as small and dry lesions, whereas big, water-soaked lesions developed on the susceptible accession within 48 hai. Investigations of the defence responses of the two accessions showed accumulation of H2O2 at penetration sites beneath appressoria in the moderately resistant, but to a lesser extent in the susceptible accession. Such H2O2 accumulation correlated with a reduction in penetration frequency and a lower level of hyphal growth after infection in the moderately resistant accession. There was a rapid and early increase in total peroxidase as well as β-1,3-glucanase activity in the moderately resistant compared to the susceptible accession. These results indicate that fungal penetration and development in watermelon are inhibited by a consorted action of different responses including accumulation of H2O2, peroxidase and β-1,3-glucanase.
AB - Infection biology and defence responses of watermelon attacked by Stagonosporopsis cucurbitacearum (syn. Didymella bryoniae) were studied in two genotypes, accessions PI189225 (moderately resistant) and 232-0125/B (susceptible). On intact leaf surfaces, spores started to germinate 14 h after inoculation (hai) with one to three germ tubes, which subsequently developed and formed appressoria. Invasion of the host tissue started at 20 hai by direct penetration from appressoria or occasionally indirectly through stomata. In the susceptible accession, a significantly higher number of direct penetrations were observed than in the moderately resistant. After invasion, hyphal colonisation was restricted in the intercellular spaces in the moderately resistant accession, whereas they developed extensively, causing tissue decay, in the susceptible accession. Macroscopic symptoms were seen in leaves of the moderately resistant accession as small and dry lesions, whereas big, water-soaked lesions developed on the susceptible accession within 48 hai. Investigations of the defence responses of the two accessions showed accumulation of H2O2 at penetration sites beneath appressoria in the moderately resistant, but to a lesser extent in the susceptible accession. Such H2O2 accumulation correlated with a reduction in penetration frequency and a lower level of hyphal growth after infection in the moderately resistant accession. There was a rapid and early increase in total peroxidase as well as β-1,3-glucanase activity in the moderately resistant compared to the susceptible accession. These results indicate that fungal penetration and development in watermelon are inhibited by a consorted action of different responses including accumulation of H2O2, peroxidase and β-1,3-glucanase.
KW - gummy stem blight
KW - HO
KW - microscopy
KW - peroxidase activity
KW - peroxidase isozymes
KW - β-1,3-glucanase activity
U2 - 10.3390/agriculture14030380
DO - 10.3390/agriculture14030380
M3 - Journal article
AN - SCOPUS:85188826636
VL - 14
JO - Agriculture
JF - Agriculture
SN - 2077-0472
IS - 3
M1 - 380
ER -
ID: 387742230