Browsing by Author "Tekin, Fatih"

Now showing 1 - 2 of 2

Alternaria Alternata Causing Inner Black Rot of Lemon (Citrus Limon) Fruits in Turkey: Genetic Diversity and Characterisation
(Academic Press Ltd- Elsevier Science Ltd, 2023) Gunen, Tacettin Utku; Ozer, Goksel; Dervis, Sibel; Guney, Inci Guler; Tekin, Fatih
The market sales of symptomless lemons in 2020 revealed a persistent and severe internal black rot with browning of the membrane wall and juice sac. To investigate the causal agent, externally symptom-free lemons from Mediterranean locations were sampled from supermarkets, local markets, and bazaars in three southeastern Turkish provinces. Internal black rot symptoms were observed in 13.69% of the 1300 externally symptomless fruits, and Alternaria was isolated from 96.63% of those exhibiting these symptoms. Morphological analysis confirmed the identity of Alternaria alternata in 26 representative isolates collected from various markets and bazaars. To examine genetic diversity or polymorphisms, start codon targeted (SCoT) markers were used. Species identification was based on the sequences of translation elongation factor 1-alpha (TEF 1-alpha), RNA polymerase second largest subunit (RPB2), and glyceraldehyde-3-phosphate dehydrogenase (GAPDH). SCoT 29 exhibited the highest amount of polymorphic amplicons, with 18 polymorphic bands scored when compared to the other six scoreable markers. The 26 representative isolates from various markets and bazaars were divided into four clades by SCoT 29. However, multilocus sequence analyses confirmed the identification of a single species, A. alternata. In terms of virulence and the impact of temperature on growth, representative isolates from four SCoT clusters were evaluated. Data suggests that SCoT markers can be used to evaluate virulence-based polymorphism in A. alternata; nonetheless, all clades showed comparable temperature responses, with 25 degrees C being the optimum. There was also no association between individual morphotypes and SCoT clade membership. Due to the lack of obvious signs on lemon fruits, producers, merchants, and consumers are unable to identify black rot, and the widespread presence of A. alternata in lemons may pose a significant risk that must be avoided at all costs.
Citation - WoS: 2
Citation - Scopus: 1
Development of an LSU rRNA-Targeted qPCR Assay and Transcriptional Profiling of Defense-Related Genes to Elucidate Barley Resistance to Bipolaris Sorokiniana
(Academic Press Ltd - Elsevier Science Ltd, 2025) Alkan, Mehtap; Bozoglu, Tugba; Yeken, Muberra; Yeken, Mehmet Zahit; Emiralioglu, Orkun; Tekin, Fatih; Ozer, Goksel
Spot blotch, caused by Bipolaris sorokiniana, severely limits global barley production. This study characterized five isolates from Bolu, T & uuml;rkiye, and screened 95 barley cultivars for resistance to the most aggressive isolate (B_BS01) using a 1-9 disease severity scale. Cultivars Gazda, Dara, Hilal, Nonius, and Bravo exhibited the highest resistance (Disease severity index: 35.00 %-36.67 %), forming a statistically distinct group. A quantitative PCR assay targeting the LSU rRNA locus of B. sorokiniana was developed, detecting pathogen DNA down to 0.1 pg with high specificity. This assay quantified starkly different colonization dynamics: pathogen DNA was effectively suppressed in resistant cultivars (Dara, Gazda), while it proliferated rapidly in susceptible ones (Merit, B & uuml;lb & uuml;l), resulting in up to 15-fold higher pathogen loads by 4 days post-inoculation. Temporal expression profiling of defense-related genes (PR1, PR2, PR3, PR5, PR10, CSD, LOX, PAL) was conducted in Dara and Merit. Notably, PR1 and PR10 were more strongly induced in Merit (17.06- and 10.56-fold at 72 h post-inoculation), whereas PR3 was preferentially upregulated in Dara. PR5 and LOX were downregulated in both cultivars; CSD showed moderate induction, and PR2 remained relatively stable. The combination of a sensitive qPCR assay and gene expression profiling provides robust tools for resistance screening and supports targeted breeding for spot blotch resistance in barley.