Zymoseptoria tritici (Desm. Quaedvlieg & Crous), known as the wheat leaf spot disease agent, is a highly virulent fungus that induces blotch and necrosis on leaves. Although it is known to cause severe infections under humid conditions, recent observations suggest that it can also infect wheat leaves under drought and high-temperature conditions, possibly influenced by global warming. Recent findings showed that Z. tritici could easily tolerate various abiotic stresses, including drought, water stress, salinity, and temperature. It has been evident that the fungus can tolerate pesticide stress, as indicated by the increased frequency and number of pesticide applications throughout the growing season. Under stress conditions, the fungi, unlike crop plants, could easily tolerate stress by rapidly modifying gene expression and reducing spore production and mycelial growth without downregulating major biochemical components that play significant roles in pathogenicity and virulence. Z. tritici can accumulate melanin under stress conditions; therefore, an increase in pathogenicity under drought or salinity stress is not unexpected. Recent studies have shown that the pathogenicity of the fungus is increasing, and more virulent, toxin-producing pathogens might emerge in the future. Since drought and high-temperature stresses significantly affect crop plants, the adaptation of pathogenic microorganisms to these conditions could be inevitable if abiotic stress persists. Under these circumstances, the crop loss would be more pronounced. A critical aspect of this process is the assessment of DNA integrity in both wheat and the pathogen under drought stress conditions. The organism that better maintains DNA integrity is considered to exhibit greater drought tolerance. Therefore, our main target should be DNA health when developing or breeding new wheat varieties, considering double- or even multiple-stress conditions. We should finally state that we are very optimistic about generating highly stress-tolerant wheat varieties via metabolomic and proteomic approaches without compromising quality. However, the impact and combination of stress factors are becoming increasingly complex.

Candidatus phytoplasma affects a wide range of host plants. In recent years, the severity and distribution of the disease have increase many fold. The present study isolated the pathogen from leaves (chlorosis), dried branches, and the other tissues of the infected tree. Acacia trees (n=15) showing severe yellowing and desiccation in the landscape areas of Şanlıurfa province were sampled from the buds (V-shaped) in three different parts of the branches, backward from the top of the branches during the flowering period, and from the middle veins of the leaves on the same branch during the leafing period. Samples were initially amplified using the universal primer pair R16F1/R16R0 and subsequently subjected to nested PCR with the primer pair R16F2n/R2. The results indicated that, on average, 2 out of 15 buds collected from the apical parts of the branches, 11 out of 15 from the middle, and 6 out of 15 from the basal parts were infected with ‘Candidatus Phytoplasma australasia’. Moreover, all samples collected from the midribs of these 15 trees were found to be infected with Ca. P. australasia.

Tomato plant, which is an important source of income in the agricultural economy in the world and in our country, is very sensitive to biotic and abiotic stress factors. Neoscytalidium dimidiatum, which causes shoot and stem drying, leaf blight, root rot and necrosis of the transmission bundle, has recently been detected in tomato plants in our region. In this study, different tissues (leaf, shoot, stem and root) of tomato plants were inoculated with different methods (spray, injection, pricking, wounding, inoculation with wheat, root dipping in spore solution). No treatment was applied to the control plants. Symptom index values of all inoculated plants increased and the disease agent caused infection regardless of which tissue of the plant it entered. Inoculation from the root zone was found to be more effective. These findings were also supported by physiological parameters. In this study, in addition to the known aggressiveness of the pathogen, it was found that the ability to infect was still dependent on the inoculation method, with only the degree of pathogenicity differing. It has been observed that cultural measures, insect vector control or the assumption that the pathogen can enter through wounds are not effective in controlling the pathogen. The use of resistant varieties and the need to increase the defence mechanism of existing plants by biochemical means were emphasised in the main control of the disease agent.

Chickpea is a legume that grows in most parts of the world. It is negatively affected by abiotic and biotic factors like drought and fungal diseases, respectively. One of the most important soil-borne pathogens affecting chickpeas is Fusarium oxysporum f.sp. ciceris (Foc). Its population dynamics in the soil are affected by fluctuations in soil water content and host characteristics. For the last three decades, drought has been common in most areas of the world due to global warming. Drought stress decreases the quality and quantity of the chickpeas, particularly where soil-borne pathogens are the main stress factor for plants. The use of both drought-tolerant and disease-resistant cultivars may be the only option for cost-effective yield production. In this study, we screened the seeds of twelve chickpea genotypes WR-315, JG-62, C-104, JG-74, CPS-1, BG-212, ANNIGERI, CHAFFA, BG-215, UC-27, ILC-82, and K-850 for drought tolerance at increasing polyethylene glycol (PEG) concentrations (0-, 5-, 7.5-, 10-, 15-, 20-, 25-, 30- and 50%) to create drought stress conditions at different severities. The performances of genotypes that were previously tested in Foc resistance/susceptibility studies were assessed in terms of percentage of germination, radicle and hypocotyl length, germination energy, germination rate index, mean germination time, and vigor index in drought conditions. We determined the genotypes of C-104, CPS-1, and WR-315 as drought-susceptible, moderately drought-tolerant, and drought-tolerant, respectively. We then elucidated the stress levels of selected genotypes (20-day-old seedlings) at 0–15% PEG conditions via measuring proline and malondialdehyde (MDA) contents. Our findings showed that genotypes that were resistant to Foc also exhibited drought tolerance. The responses of chickpea genotypes infected with Foc under drought conditions are the next step to assess the combined stress on chickpea genotypes.

This study aims to elucidate the physiological and biochemical alterations induced by parasitic Cuscuta sp. (dodder) in lucerne (Medicago sativa L.), a key forage crop. Comparative analyses between infected and healthy plants revealed that significant reductions in chlorophyll a, b, and total chlorophyll, and protein levels in the leaf and stem tissues of Cuscuta-infested plants were evident. The parasitic infection led to increased activities in antioxidant enzymes such as catalase (CAT) and peroxidase (POX) in stems, but not in leaves. Phenolic compounds were significantly lower both in leaves and stems of dodder-infected lucerne plants. No statistically significant changes were detected in jasmonic acid (JA) and salicylic acid (SA) levels in both plant parts, suggesting that classical defense signaling pathways may not be predominantly activated under Cuscuta-mediated stress. Possibly, host defense might be impaired. Histological examinations demonstrated active structural defense responses, including localized tissue remodeling and the formation of callose-like structures at haustorial penetration sites. DNA fragmentations showed that Cuscuta-infected M. sativa plants exhibited slightly higher instability. Collectively, these findings provide novel insights into the molecular and biochemical basis of the Cuscuta-lucerne interactions and highlight the need for further investigation into host defense mechanisms. We assume that active defense structural parts at early growth stages of lucerne or hypersensitive-type responses occurring in the early penetration phase might fend off the invading holoparasite. The results also offer a valuable foundation for the development of Cuscuta-resistant lucerne cultivars and support the design of integrated, sustainable weed management strategies to mitigate the detrimental effects of parasitic plants on forage production systems.

Olive is a perennial tree able to grow and survive in Mediterranean conditions due to its climate adaptations. In this study, we observed a new disease characterised by leaf tip blight, shoot blight, and dieback in olive trees in the Southeast Anatolian region of T & uuml;rkiye. Six fungal isolates were obtained from the symptomatic trees. Classical methods based on macroscopic and microscopic observations revealed that the isolates were similar to Sordaria macrospora. Total DNA was isolated and PCR-amplified with primer pairs for the ITS, LSU, beta-tubulin, and Tef-1 alpha gene regions, and the resulting sequences were BLASTed in the NCBI database. The similarity was 99%-100% to isolates of S. macrospora. The similarity of the pathogen to other Sordaria spp. isolates was determined by constructing a phylogenetic tree using MEGA X software and the neighbour-joining method. Out of six isolates, one representative isolate was selected for subsequent studies. In pathogenicity tests on 2-year-old olive seedlings, blight was observed starting from the tips of leaves and shoots to the base, and the pathogen was successfully reisolated, fulfilling Koch's postulates. This is the first report of S. macrospora acting as a pathogen in olive trees.

Neoscytalidium novaehollandiae has recently caused economic losses by inducing drying, cancerous wounds and deaths in plants. In this study, the in vitro activities of Thiophanatemethyl + Tetraconazole (Y*) and Pyraclastrobin + Fluxapyroxad (P*) active substances and the formulation applied as a mixture of these two fungicides (Y*+P*) were investigated on Neoscytalidium novaehollandiae isolated from pistachio trees. Field doses (mg L-¹) of fungicides were adapted to Petri dishes and applied in four treatments. Mycelial discs from N. novaehollandiae isolates were soaked in fungicide solution and placed in PDA medium to simulate natural field conditions. Mycelial growth diameters in Petri dishes were measured and % inhibition rates of fungicides were calculated at the end of the experiment. When the Petri dishes in the control group were completely covered, the experiment was terminated. As a result of the application, Y* fungicide showed an inhibition effect of 61.2%, P* fungicide showed an inhibition effect of 89.3% and P*+Y* application showed an inhibition effect of 100% and it was found that the fungicide mixture was more effective. In addition, the fungustatic and fungicidal activity of the fungicides was investigated in a revitalisation test. It was found that the Y* fungicide, which grew to 0.95 cm but did not form conidia, was fungistatic and the P* and Y*+P* fungicides were fungicidal. Fungicidal substances can control pathogens, while fungistatic substances suppress them. There is no registered product to control N. novaehollandiae, so this study is important.

Neoscytalidium novaehollandiae is a highly destructive fungus that causes serious yield losses in economically important crop plants. A reliable and rapid inoculation method for Neoscytalidium novaehollandiae was evaluated in eggplant, tomato and pepper seedlings under greenhouse conditions. Three different inoculation methods namely, cut-stem, spray, and injection were evaluated on tomato, pepper, and aubergine seedlings. The results showed that the cut-stem and injection methods were effective on tomato, pepper, and aubergine plants while the spray inoculation method was not found effective. Especially, the cut-stem inoculation method appears to be the most appropriate method for pathogenicity and screening of seedlings for N. Novaehollandiae pathogenicity

This study investigated the physiological and biochemical tolerance and response, cadmium (Cd) accumulation capacity of the mustard plant (Brassica juncea L.) to different doses of Cd (0.0 (control)-, 25-, 50-, 100-, 200-, and 300 ppm) under greenhouse conditions. After harvesting the mustard plant, physiological parameters (plant length, plant fresh and dry weight, roots fresh weight and dry weight), and biochemical parameters such as chlorophyll a (Chl a), and chlorophyll b (Chl b), carotenoids, proline, malondialdehyde (MDA), antioxidant enzymes such as peroxidase (POX), and catalase (CAT) were examined. Cd content was measured in leaves and roots to determine phytoextraction capacity. Cd stress decreases plant and root fresh weight (Fwt) and dry weight (Dwt). Chl a-Chl b, and carotenoid contents 100 ppm of Cd decrease Cd doses increase p≤0.05. The osmolyte molecule proline increased to 100 ppm Cd dose and then declined to 300 ppm. Accumulation of MDA (2.9 to 33.8 nmol g-1 Fwt), H2O2 (2.9 to 30.4 µmol g-1 Fwt), and antioxidant enzymes (POX and CAT) showed an increasing trend with increasing Cd doses, p≤0.05. Cd accumulation in leaves (0.0 to 53.8. mg kg-1 ) and roots (0.0 to 67.7. mg kg-1 ) increased depending on the applied Cd concentration. The highest Cd accumulation was determined at 300 ppm Cd level. These findings suggest that mustard plants can accumulate high levels of Cd in both leaves and roots, indicating that they are hyperaccumulators. As a result, mustard plants can be utilized as phytoremediation plants in Cd-contaminated soils.

Due to being sessile, plants develop a broad range of defense pathways when they face abiotic or biotic stress factors. Although plants are subjected to more than one type of stress at a time in nature, the combined effects of either multiple stresses of one kind (abiotic or biotic) or more kinds (abiotic and biotic) have now been realized in agricultural lands due to increases in global warming and environmental pollution, along with population increases. Soil-borne pathogens, or pathogens infecting aerial parts, can have devastating effects on plants when combined with other stressors. Obtaining yields or crops from sensitive or moderately resistant plants could be impossible, and it could be very difficult from resistant plants. The mechanisms of combined stress in many plants have previously been studied and elucidated. Recent studies proposed new defense pathways and mechanisms through signaling cascades. In light of these mechanisms, it is now time to develop appropriate strategies for crop protection under multiple stress conditions. This may involve using disease-resistant or stress-tolerant plant varieties, implementing proper irrigation and drainage practices, and improving soil quality. However, generation of both stress-tolerant and disease-resistant crop plants is of crucial importance. The establishment of a database and understanding of the defense mechanisms under combined stress conditions would be meaningful for the development of resistant and tolerant plants. It is clear that leaf pathogens show great tolerance to salinity stress and result in pathogenicity in crop plants. We noticed that regulation of the stomata through biochemical applications and some effort with the upregulation of the minor gene expressions indirectly involved with the defense mechanisms could be a great way to increase the defense metabolites without interfering with quality parameters. In this review, we selected wheat as a model plant and Zymoseptoria tritici as a model leaf pathogen to evaluate the defense mechanisms under saline conditions through physiological, biochemical, and molecular pathways and suggested various ways to generate tolerant and resistant cereal plants.

Şanlıurfa ili peyzaj alanlarındaki çam ağaçlarında son zamanlarda sürgün yanıklığı ve geriye doğru ölümler şeklinde hastalık belirtileri görülmüştür. Bölgede bu tür hastalık belirtisi gösteren ağaçların sayısı gittikçe artmaktadır. Tipik hastalık belirtisi gösteren ağaçlardan yapılan izolasyonlar sonucunda, PDA (Patates Dekstroz Agar) besi yerinde gelişen fungal izolatların koloni ve sporlarının morfolojik gözlemlere dayalı olarak hastalık etmeninin Alternaria spp.’a ait olduğu belirlenmiştir. Bölge izolatları arasından seçilen temsili izolatlarla yapılan yapay inokulasyon sonucu çam fidanları üzerinde doğal enfekteli çam ağaçlarında görülen belirtilere benzer belirtiler gözlenmiş olup, fungal etmen bu dokulardan yeniden izole edilmiştir. İzole edilen fungal etmenin morfolojik tanısı Internal Transcribed Spacer (ITS) gen bölgesi (ITS1-5.8S rDNA-ITS4) ve large subunit (LSU) gen bölgesi (NL1-NL4) çoğaltılıp dizilenmesi ile moleküler olarak da teyit edilmiştir. Gen bankasına kaydedilen temsili izolatın (ITS için erişim no: OR145842; LSU için erişim no; OR616592) sekans sonucu Alternaria alternata izolatı ile %99.9 oranında benzerlik göstermiştir. Elde edilen morfolojik ve moleküler çalışma sonuçları A. alternata’nın Türkiye’de yetişen çam ağaçlarında sürgün yanıklığı ve geriye doğru ölüm hastalığı etmeni olduğu ilk kez bu çalışma ile belirlenmiştir.

Orman ağaçları ile sebze ve meyvelerde önemli kayıplara yol açan Alternaria alternata, ruhsatlı fungisitler ile kontrol edilmek istenmesine rağmen arzu edilen sonuç elde edilememektedir. Bu çalışmada etmene karşı bazı fungisitlerin aktif maddeleri (Fosforoz asit (D*), Thiophanate methyl + Tetraconazole (Y*), Pyraclastrobin + Fluxapyroxad (P*), Metrafenone (V*), Azoxystrobin + Propiconazole (As), Azoxystrobin + Cyproconazole (Ar)) ile bunların çeşitli kombinasyonları test edilmiştir. Çalışmada tüm fungisitlerin arazi koşullarındaki dozları (mg L-1) kullanılmış ve her uygulama dört tekerrürlü olarak yapılmıştır. Saf olarak Patates Dekstroz Agar (PDA) ortamında geliştirilen A. alternata izolatlarından elde edilen miselyal diskler (9 mm çap) ilgili fungisit solüsyonlarına 45 saniye süre ile batırılmış ve PDA ortamına aktarılmıştır. Çalışmada izolatların miselyal gelişme çapları iki gün ara ile ölçülmüş ve deneme sonunda izolatların fungisitlere karşı gösterdikleri % engellenme oranları hesaplanmıştır. A. alternata’nın 18 günlük gelişimi sonucu misel engelleme oranı en etkili bulunan fungisitler sırası ile %90.6 ile P*, %88.5 ile Ar*, %84.8 ile As, %71.8 ile Y*bulunurken en az etkili bulunan fungisitler ise %7.2 ile V* ve %37.4 ile D* olmuştur. Etmene karşı mücadelede in vitro koşullarda etkili bulunan fungisitlerin arazi koşullarında da etkili olabileceği ümitvar görülmüştür. Ayrıca P* ve Ar* aktif maddeli fungisitlerin karışımı, bu fungisitlerin tekli uygulanması ile kıyaslanmış, fungisit kombinasyonlarının etkinliği tartışılmıştır. A. alternata’ya karşı bu aktif maddelerin ruhsatlı olmaması ve alternatif fungisitlerin etkinliklerinin bilinmemesi, geniş konukçu kitlesine sahip olan ve farklı orman ve meyve ağaçları ile sebzeleri enfekte edebilen patojenin kimyasal mücadelesi üzerinde durulmuştur.

Mikroorganizmaların gelişimini sağlamak için hazırlanan besiyerlerinde bulaşıklığı önlemek amacı ile kullanılan antibiyotiklerin mikroorganizmaların gelişimini etkilediği konusunda bazı öngörüler mevcuttur. Bu çalışmada kullanılan antibiyotiğin misel gelişimi üzerindeki inhibitör etkisi Alternaria alternata için karşılaştırılmıştır. Fungal etmen fungisit [P* (pyraclastrobin+fluxapyroxad), D* (phosphorous acid), Ar* (azoxystrobin+cyproconazole), B* (prochloraz+trifloxystrobin+cyproconazole), ve Y* (thiophanate methyl+ tetraconazole)] ile birlikte tetracycline ve streptomycine içeren/içermeyen Patates Dekstroz Agar (PDA) ortamında gelişime bırakılmıştır. Antibiyotik içeren fungisitli ortamlarda fungal etmenin engellenme oranları sırasıyla, P* ve B* fungisitleri için %100, Ar* için %46.08, Y* için 35.29, D* için %8.63 olurken, antibiyotik içermeyen ortamlarda bu durum P* ve B* fungisitleri için %100, Ar* için %46.47, Y* için %30 ve D* için %18.82 olmuştur. Fungal etmen fungisit testine tabi tutulduğunda, her iki ortamda fungisit uygulamalarının birbirleri arasında istatistiki açıdan önemli bir fark olduğu tespit edilmiştir (P≤0.05). Ortamda bulunan antibiyotik varlığının deneysel sonucu etkilemediği tespit edilmiş, bu durum istatistiki olarak önemsiz bulunmuştur (P≥0.05). Yapılan çalışma sonuçları in vitro koşullarda fungal etmenlerin strese maruz kaldığı durumlarda (pestisit, NaCl, hormon, vitamin, ağır metaller vb.) besi ortamına antibiyotik eklenmesinin deneme sonuçlarını etkilemeyeceği kanaatine varılmıştır.

Increasing incidences of phytoplasma infestations in Almond trees warrants the better management approach to prevent yield losses. Disease management rely on identification of the pathogen based on molecular profiling. The present study aimed, to identify the phytoplasma agent in almond trees and to measure the biochemical responses it causes in the host. Direct and Nested PCRs performed using phytoplasma specific primer pairs 16S rRNA, detected the presence of phytoplasma agent in symptomatic trees but not in symptomless trees. Phylogeny based on the sequence analysis revealed that the infecting agent was closely related to 'Candidatus Phytoplasma phoenicium' (16SrIX-B subgroup). Then the study was carried out to determine the responses of physiological and biochemical mechanisms in almond trees infected with phytoplasma. Total chlorophyll and protein contents of infected almond trees were lower compared to healthy control, on the other hand, the levels of catalase and peroxidase activity increased in infected trees. Higher levels of stress-related metabolites such as proline (20.53-39.23 mu mol/g), phenol (3.00-4.44 mg GAE/g), salicylic (94.96-138.22 ng SA/mg protein) and jasmonic acid (965.86-1465.10 ng JA/mg protein) were observed in infected trees compared to asymptomatic trees, respectively in healthy and infected trees. The results showed that the Ca. P. phoenicium, which was detected for the first time in T & uuml;rkiye, was able to change the physiological and biochemical mechanisms. The pathogenic agent could possess a potential danger in almond production areas. It is crucially important that this agent should be considered in certification programs.

Phytochemical screening and Antimicrobial activity of the leaves of Memecylon umbellatum burm. F.Subban Murugesan, Annamalai Pannerselvam, Arumugame Chanemougame Tangavelou

Neoscytalidium cinsine ait türler son zamanlarda dünyada ve Türkiye’de kültür, peyzaj ve orman bitkilerinde önemli ekonomik kayıplara yol açmaktadır. N. novaehollandiae türü tek yıllık bitkilerde kurumalara ve iletim demetlerinde kararmalara yol açarken ağaçlarda gövde çatlamalarına kabuk altı nekrozlarına ve dal kurumalarına yol açmaktadır. Bölgemizde yeni yayılmaya başlayan bu hastalık etmenine karşı herhangi bir mücadele yöntemi bilinmemektedir. Bu çalışmada -5 ila 40ºC aralığındaki farklı sıcaklık değerlerinde 3 günlük süre içinde N. novaehollandiae etmeninin misel gelişimleri ölçülmüştür. Hastalık etmeni 15 ve 35ºC aralığında gelişme gösterirken optimum gelişimleri 25 ve 30ºC aralığında bulunmuştur. Fakat etmenin misellerinin 10ºC ve 40ºC’lerde 4. günde gelişmeye başladığı gözlenmiştir. Bu sıcaklık çalışması N. novaehollandiae etmenine karşı mücadele zamanının belirlenmesinde önemli bir adım olmuş ve bölgemizde son zamanlarda ortaya çıkan ve epidemi yapma potansiyeline sahip fungal etmenin fizyolojik karakterinin aydınlatılması hedeflenmiştir.

Bacterial speck Pseudomonas syringae pv. tomato (Pst) (Okabe) Young, Dye, & Wilkie is a widespread disease in tomato plants. Four plant growth-promoting rhizobacterial (PGPR) strains 5(3), 68(2), 36(1), and 47(3) played a significant role (50% and higher) in reducing spot disease severity. Selected strains were identified as Pseudomonas koreensis 5(3), Bacillus mycoides 68(2), Bacillus mojavensis 36(1), and Bacillus simplex 47(3) using the MALDI Biotyper classification system. In planta assay using tomato seedlings were inoculated with the bacterial strains alone or in dual combination. Pseudomonas koreensis 5(3) (51.9%–74.29%) and Bacillus mycoides 68(2) (36.70%–65.56%) both provided a significant reduction in foliar severity caused by bacterial speck disease agent Pseudomonas syringae pv. tomato (Okabe) Young, Dye, & Wilkie. Bacillus simplex 47(3) and Bacillus mojavensis 36(1) were successful only in combined treatments. Defense enzymes Proline, Peroxidase, and Catalase were induced by PGPR strains in comparison with those of control plants. Hydrogen peroxide (H 2 O 2 ) and callose deposition were evident at reaction sites induced by PGPR strains. The accumulation of callose, H 2 O 2 , and high levels of defense enzymes via the treatment of PGPRs might play a significant role in a practical, safe, and effective way to control Pseudomonas syringae pv. tomato.

Fig (Ficus carica) trees exhibited symptoms of little leaf, mottling and deformation in Sanliurfa province, Turkey. Poylmerase chain reaction (PCR) through direct and nested-PCR, phylogeny based on the sequence analysis revealed that the infecting agent was closely related to 'Candidatus Phytoplasma aurantifolia' (16SrII-B subgroup). This is the first report of Ca. P. aurantifolia in fig trees in Turkey.