First Report of Collar and Root Rot of Lettuce Caused by Plectosphaerella cucumerina in Serbia
Аутори
Mihajlović, MilicaHrustić, Jovana
Vučurović, Ana
Grahovac, Mila
Budakov, Dragana
Dudaš, Tatjana
Pešić, Brankica
Остала ауторства
Cox, KerikИнформативни прилог (Објављена верзија)
Метаподаци
Приказ свих података о документуАпстракт
In March 2021, unusual plant stunting and collar and wet root rot of
lettuce (Lactuca sativa L.) during the rosette stage were observed in two
commercial fields in Serbia (44°589N, 20°329E; 44°459N, 20°439E). Disease
incidence in the fields ( 0.9 ha each) was approximately 15 and 20%,
respectively. Initial above-ground symptoms were yellowing and wilting of
leaves, while below-ground symptoms were collar and wet root rot and
necrotic lesions. Eventually, whole plants wilted, collapsed, and died. A total
of 35 symptomatic plants were collected from the fields and diseased tissues
were cut into small pieces, surface sterilized, and plated on potato dextrose
agar. Isolation resulted in 20 morphologically uniform monoconidial isolates.
The isolates formed white to creamy colonies, which gradually became
salmon pink, slimy, or moist in appearance, with sparse aerial mycelia.
Numerous hyphal coils with conidiophores and hyaline, smooth-surfaced,
ellipsoid to ovoid, septate or as...eptate conidia were formed (4.5 to 10.1 ×
1.2 to 3.7 μm [n = 100]). To confirm the species identity, the internal
transcribed spacer (ITS) region and the D1/D2 region of a selected representative
isolate 13-3-c were amplified and sequenced by using the primer
pairs ITS1/ITS4 (White et al. 1990) and N1/N2 (O’Donnell and Gray 1995),
respectively. The sequences were deposited in GenBank (ITS, OR880564;
D1/D2, OR880567). Sequence analysis revealed 100% nucleotide identity
with Plectosphaerella cucumerina isolates from different countries
deposited in NCBI GenBank, including the isolates MH860704 (Vu et al.
2019) (ITS region) and KY662256 (Su et al. 2017) (D1/D2 region).
Neighbor-joining analysis was conducted based on combined ITS and D1/
D2 regions, and the tree was constructed with the substitution models
(1,000 bootstrap). Combined phylogeny confirmed that the sequences shared
a common clade with P. cucumerina. Hence, morphological, microscopic,
and molecular characterization confirmed the pathogen as P. cucumerina
(Carlucci et al. 2012; Palm et al. 1995). In a pathogenicity assay, 10 isolates
were tested. Five 30-day-old lettuce plants (cv. Majska Kraljica) per isolate
were root-dipped in the conidial suspensions (1 × 105 conidia/ml). The
10 inoculated plants were transplanted in l-liter pots containing the sterile
substrate (Floragard, Germany). Plants treated with sterile distilled water
were used as controls. Plants were maintained in a greenhouse at 25 to 28°C
under a 12-h photoperiod (Cai et al. 2021). Four weeks after inoculation,
stunting, chlorosis, and wilting of plants were observed, while collars and
roots exhibited typical decaying symptoms. No symptoms were observed on
the control plants. The pathogen was reisolated from symptomatic tissue as
previously described. Koch’s postulates were completed by confirming the
identity of reisolates based on the morphological features. To our knowledge,
this is the first report of P. cucumerina on lettuce or any other crops in
Serbia. P. cucumerina is already known as a pathogen of lettuce and other
hosts grown in many countries worldwide, as well as in some European
countries (Belgium, England, Italy, Netherland, and Switzerland) (Zhang
et al. 2019). This emerging pathogen may cause significant economic losses
in lettuce production in Serbia and in the entire Balkan region. Our results
may help to develop effective management strategies based on accurate and
timely identification and regular pathogen monitoring.
Кључне речи:
D1/D2 region / Lactuca sativa / pathogen detectionИзвор:
Plant Disease, 2024, 108, 4, 1112-1112Издавач:
- St. Paul, MN : American Phytopatholoical Society
Пројекти:
- Министарство науке, технолошког развоја и иновација Републике Србије, институционално финансирање - 200214 (Институт за пестициде и заштиту животне средине, Београд) (RS-MESTD-inst-2020-200214)
- Министарство науке, технолошког развоја и иновација Републике Србије, институционално финансирање - 200117 (Универзитет у Новом Саду, Пољопривредни факултет) (RS-MESTD-inst-2020-200117)
- Slovenian Research and Innovation Agency (ARIS), Republic of Slovenia Core Financing (P4-0165)