Pathogenicity of Some Fusarium Species Associated with Superficial Blemishes of Potato Tubers

Abstract

A b s t r a c tAs an organ for reserve and propagation, the tuber grows underground and is in contact with soil-borne microorganisms, making it potentially exposed to blemishes. erefore, the objective of this study was the possibility of using some modern methods of molecular diagnostics and detection of the presence of fungal contaminants in potato blemishes in Al-Qasim (Saudi Arabia). Polygonal lesions were the most observed blemish type in the collected samples. One hundred and sixty isolates were recovered from di erent types of blemishes obtained in this study. Fusarium, Penicillium, Ilyonectria, Alternaria and Rhizoctonia were the most common genera collected from different blemish types. Using ITS region sequencing, all collected fungi were identified at the species level. All Fusarium strains collected during this study were used to detect their pathogenicity against potato tubers. is is the first comprehensive report on the identification of major pathogenic fungi isolated from potato tuber blemishes in Saudi Arabia.

Identification of Fusarium spp. Associated with Potato Tubers in Upper Egypt by Morphological and Molecular Characters

“…This result is in agreement with several auhtors [13,45,46] who reported that F. sambucinum and F. oxysporium were the most frequently Fusarium species associated with potato dry rot in Egypt. According to Gashgari and Gherbawy [32] isolated Fusarium oxysporum, F. redolens, F. solani, F. sambucinum and F. graminearum from Saudi potato tubers. However, the genus Fusarium is complex and morphological differences may be difficult to observe.…”

“…Bayona et al [62] confirmed the pathogenicity of two F. oxysporum isolates associated with potato dry rot in Colombia. Gashgari and Gherbawy [32] recorded that Fusarium oxysporum strains (KAUF12.1, KAUF12.2, KAUF12.3 and KAUF12.4) isolated from Suadi potato tubers did not show any pathogenicity against tubers. Chehri et al [63] in Malaysia studied the occurrence and pathogenicity of Fusarium spp.…”

“…An enzyme capable of degrading plant cell wall polysaccharides is considered to play an important role in pathogenesis [30,31]. Gashgari and Gherbawy [32] reported that Fusarium spp. showed variation in pathogenicity level.…”

The effect of Pseudomonas chlororaphis subsp. aurantiaca strain Q16 able to inhibit Fusarium oxysporum growth on potato yield

“…It is responsible for severe vascular wilts, and can cause tuber rot. Reduction of the yield caused by dry rot is on average 6%, with possible losses up to 25% (Gashgari & Gherbawy 2013), while almost complete loss of stored commercial potatoes varieties was reported in Turkey (Eken et al, 2000).…”

Assessment of Potato Tuber Resistance Against Dry Rot

“…DOI: 10.1515/plass-2017-0021 Pathogenicity tests are often described in literature, but no unified dry rot resistance assay has been presented. The differences cover inoculum preparation (conidial suspension, agar plugs with Fusarium mycelium), temperature (4°C , 10°C, 16°C, 20°C) and time (20, 21, 30, 35 days) of incubation or lesion size scoring (depth of necrosis, depth and width averages, lesion in mm 2 , rot volume in mm 3 , 1-9 scale according to the percentage of the diseased area); common conditions comprise the absence of light and maintenance of high relative humidity during the incubation period (Gachango et al, 2012;Gashgari and Gherbawy, 2013;Peters et al, 2008a;Peters et al, 2008b;Du et al, 2012;Zarzycka, 2001). Instead of wounded tubers, tuber slices inoculated with inoculum plugs have also been proposed for pathogenicity tests (Desjardins and Gardner, 1989).…”