Two new root endophyte and nematode cyst parasite species of the widely distributed genus Laburnicola

Fungal root endophytes, including the common form group of dark septate endophytes (DSEs), represent different taxonomic groups with potentially diverse life strategies. During surveys of DSE communities and of nematode cysts colonizing fungi, isolates representing Laburnicola ( Didymosphaeriaceae , Pleosporales ) lineages were discovered. Here we carried out a comprehensive study of the phylogenetic relationships and taxonomy of fungi collected from plant roots in Hungary, Mongolia, and Kazakhstan and from eggs of the cereal cyst nematode Heterodera filipjevi in Turkey. In addition to the study of the morphology and culture characteristics of the strains, four loci (internal transcribed spacer, partial large and small subunit regions of nuclear ribosomal DNA and partial translation elongation factor 1-alpha) were used to infer the molecular phylogenetic relationships of the strains within Laburnicola . The isolates were found to represent two distinct lineages, which are described here as novel species, Laburnicola nematophila and L. radiciphila . The interaction of the strains with plants and nematodes was examined using in vitro bioassays, which revealed endophytic interactions with the plant roots and parasitic interactions with the nematode eggs. Analyses of similar ITS sequences found in public databases revealed that members of the genus Laburnicola are widely distributed characteristic members of the plant microbiome, and they are reported as parasites of plant parasitic cyst nematodes here for the first time

Resistance response of drought and heat tolerant spring wheat lines against the cereal cyst nematode, heterodera filipjevi

Spot blotch caused by Bipolaris sorokiniana is a destructive disease of wheat worldwide. This study investigated the aggressiveness of B. sorokiniana isolates from different wheat-growing areas of Bolu province in Turkey on the cultivar Seri-82. Host susceptibility of 55 wheat cultivars was evaluated against the most aggressive isolate. Our results indicated that the cultivars Anafarta and Koç-2015 were the most resistant. A specific and sensitive qPCR assay was developed for detecting the pathogen in plant tissues and evaluating wheat plants with different resistance levels. Three primer sets, BsGAPDHF/BsGAPDHR, BsITSF/BsITSR, and BsSSUF/BsSSUR, were designed based on glyceraldehyde-3-phosphate dehydrogenase, internal transcribed spacers, and 18S rRNA loci of B. sorokiniana with detection limits of 1, 0.1, and 0.1 pg of pathogen DNA, respectively. The qPCR assay was highly sensitive and did not amplify DNA from the other closely related fungal species and host plants. The protocol differentiated wheat plants with varying degrees of resistance. The assay developed a useful tool for the quantification of the pathogen in the early stages of infection and may provide a significant contribution to a more efficient selection of wheat genotypes in breeding studies. In the present study, expression levels of PR proteins, phenylalanine ammonia-lyase, catalase, ascorbate peroxidase, and superoxide dismutase enzymes were upregulated in Anafarta (resistant) and Nenehatun (susceptible) cultivars at different post-infection time points, but more induced in the susceptible cultivar. The results showed considerable variation in the expression levels and timing of defense genes in both cultivars

Monitoring of host suitability and defense-related genes in wheat to Bipolaris sorokiniana

Spot blotch caused by Bipolaris sorokiniana is a destructive disease of wheat worldwide. This study investigated the aggressiveness of B. sorokiniana isolates from different wheat-growing areas of Bolu province in Turkey on the cultivar Seri-82. Host susceptibility of 55 wheat cultivars was evaluated against the most aggressive isolate. Our results indicated that the cultivars Anafarta and Koç-2015 were the most resistant. A specific and sensitive qPCR assay was developed for detecting the pathogen in plant tissues and evaluating wheat plants with different resistance levels. Three primer sets, BsGAPDHF/BsGAPDHR, BsITSF/BsITSR, and BsSSUF/BsSSUR, were designed based on glyceraldehyde-3-phosphate dehydrogenase, internal transcribed spacers, and 18S rRNA loci of B. sorokiniana with detection limits of 1, 0.1, and 0.1 pg of pathogen DNA, respectively. The qPCR assay was highly sensitive and did not amplify DNA from the other closely related fungal species and host plants. The protocol differentiated wheat plants with varying degrees of resistance. The assay developed a useful tool for the quantification of the pathogen in the early stages of infection and may provide a significant contribution to a more efficient selection of wheat genotypes in breeding studies. In the present study, expression levels of PR proteins, phenylalanine ammonia-lyase, catalase, ascorbate peroxidase, and superoxide dismutase enzymes were upregulated in Anafarta (resistant) and Nenehatun (susceptible) cultivars at different post-infection time points, but more induced in the susceptible cultivar. The results showed considerable variation in the expression levels and timing of defense genes in both cultivars

Genome-Wide Association Study for Multiple Biotic Stress Resistance in Synthetic Hexaploid Wheat

Genetic resistance against biotic stress is a major goal in many wheat breeding programs. However, modern wheat cultivars have a limited genetic variation for disease and pest resistance and there is always a possibility of the evolution of new diseases and pests to overcome previously identified resistance genes. A total of 125 synthetic hexaploid wheats (SHWs; 2n = 6x = 42, AABBDD, Triticum aestivum L.) were characterized for resistance to fungal pathogens that cause wheat rusts (leaf; Puccinia triticina, stem; P. graminis f.sp. tritici, and stripe; P. striiformis f.sp. tritici) and crown rot (Fusarium spp.); cereal cyst nematode (Heterodera spp.); and Hessian fly (Mayetiola destructor). A wide range of genetic variation was observed among SHWs for multiple (two to five) biotic stresses and 17 SHWs that were resistant to more than two stresses. The genomic regions and potential candidate genes conferring resistance to these biotic stresses were identified from a genome-wide association study (GWAS). This GWAS study identified 124 significant marker-trait associations (MTAs) for multiple biotic stresses and 33 of these were found within genes. Furthermore, 16 of the 33 MTAs present within genes had annotations suggesting their potential role in disease resistance. These results will be valuable for pyramiding novel genes/genomic regions conferring resistance to multiple biotic stresses from SHWs into elite bread wheat cultivars and providing further insights on a wide range of stress resistance in wheat

Genome-wide association study of root-lesion nematodes Pratylenchus species and crown rot Fusarium culmorum in bread wheat

Triticum aestivum L., also known as common wheat, is affected by many biotic stresses. Root diseases are the most difficult to tackle due to the complexity of phenotypic evaluation and the lack of resistant sources compared to other biotic stress factors. Soil-borne pathogens such as the root-lesion nematodes caused by the Pratylenchus species and crown rot caused by various Fusarium species are major wheat root diseases, causing substantial yield losses globally. A set of 189 advanced spring bread wheat lines obtained from the International Maize and Wheat Improvement Center (CIMMYT) were genotyped with 4056 single nucleotide polymorphisms (SNP) markers and screened for root-lesion nematodes and crown rot resistance. Population structure revealed that the genotypes could be divided into five subpopulations. Genome-Wide Association Studies were carried out for both resistances to Pratylenchus and Fusarium species. Based on our results, 11 different SNPs on chromosomes 1A, 1B, 2A, 3A, 4A, 5B, and 5D were significantly associated with root-lesion nematode resistance. Seven markers demonstrated association with P. neglectus, while the remaining four were linked to P. thornei resistance. In the case of crown rot, eight different markers on chromosomes 1A, 2B, 3A, 4B, 5B, and 7D were associated with Fusarium crown rot resistance. Identification and screening of root diseases is a challenging task; therefore, the newly identified resistant sources/genotypes could be exploited by breeders to be incorporated in breeding programs. The use of the identified markers in marker-assisted selection could enhance the selection process and cultivar development with root-lesion nematode and crown rot resistance

Türkiye'de bulunan yabani Emmer buğdayları (Triticum dicoccoides Koern.) ve buğday çeşitlerinin Kök lezyon nematodları (Pratylenchus thornei and P. neglectus)'na karşı dayanıklılıklarının belirlenmesi

Kök lezyon nematodları (RLN; Pratylenchus thornei ve P. neglectus) buğday köklerine saldırarak, tahıl kalitesi ve miktarında küresel olarak önemli kayıplara neden olan önemli bir bitki paraziti nematod gurubudur. Türkiye'de buğday ekiliş alanlarında yaygın olarak bulunan bu nematodlarla ancak dayanıklı çeşitler ve rotasyonla mücadele etmek mümkündür. Maalesef bugüne kadar bu nematod gurubuna karşı tamamen dayanıklı olarak tanımlanan hiçbir ticari buğday çeşidi bulunamamıştır. Bu nedenle, buğday ıslah programlarında yüksek verimli ve kaliteli buğday çeşitlerine orta derecede (kısmi) dayanıklı ebeveynler kullanılarak dayanıklılık entegre edilmeye çalışılmıştır. Bu araştırmanın amacı bazı Türk yabani Emmer'lerinin (Triticum dicoccoides) ve bazı ulusal yazlık buğday çeşitlerinin P. thornei ve P. neglectus'a karşı dayanıklılık durumlarını ortaya koymaktır. Bu amaçla her iki nematoda karşı yapılan iki farklı denemede, 32 yabani Emmer buğdayı ve 42 buğday çeşidinin, P. thornei veya P. neglectus bireylerine karşı dayanıklıkları 9 hafta boyunca kontrollü koşullar altında testlenmiştir. Sonuç olarak, P. thornei ve P. neglectus'a karşı sırasıyla 25 ve 35 buğday çeşidinin orta derecede dayanıklılık reaksiyonu sağladığı belirlenmiştir. Toplamda 17 çeşit her iki nematoda karşı dayanıklılık göstermiştir (p <0.05). Elde edilen verilere göre, tespit edilen dayanıklı buğday çeşitlerinin mevcut hatlardan daha dayanıklı olduğu belirlenmiş ve bu hatların Türkiye'deki ıslah programlarında mükemmel bir şekilde kullanılabileceği ortaya konmuştur.Root-lesion nematodes (RLN; Pratylenchus thornei and Pratylenchus neglectus) are serious plant parasitic nematodes that attack wheat roots and cause significant losses in grain quality and quantity worldwide. They are widely distributed in Turkish wheat growing areas and can be only controlled by growing resistant cultivars and nonhost crops. So far, there is no commercial wheat cultivar identified as completely resistant to the RLN is available. The objective of this research was to evaluate some Turkish wild Emmers (Triticum dicoccoides) and national spring wheat varieties for resistant to P. thornei and P. neglectus. In the experiments, 32 wild Emmers and 42 wheat cultivars were inoculated with P. thornei or P. neglectus individuals and grown under controlled conditions in a growth room for 9 weeks. The results showed that 25 and 35 wheat varieties were moderately resistant to P. thornei and P. neglectus, respectively. In total, 17 lines exhibiting multiple resistance reactions to both nematodes were in the same group with the check lines (P&lt;0.05). The identified resistant wheat accessions showed improved levels of RLN resistance over current parents and could serve as an excellent genetic pool to be used in an efficient Turkish wheatbreeding programme

Evaluation of Turkish wild Emmers (Triticum dicoccoides Koern.) and wheat varieties for resistance to the root lesion nematodes (Pratylenchus thornei and Pratylenchus neglectus)

WOS: 000369882800001Root-lesion nematodes (RLN; Pratylenchus thornei and Pratylenchus neglectus) are serious plant parasitic nematodes that attack wheat roots and cause significant losses in grain quality and quantity worldwide. They are widely distributed in Turkish wheat growing areas and can be only controlled by growing resistant cultivars and non host crops. So far, there is no commercial wheat cultivar identified as completely resistant to the RLN is available. The objective of this research was to evaluate some Turkish wild Emmers (Triticum dicoccoides) and national spring wheat varieties for resistant to P. thornei and P. neglectus. In the experiments, 32 wild Emmers and 42 wheat cultivars were inoculated with P. thornei or P. neglectus individuals and grown under controlled conditions in a growth room for 9 weeks. The results showed that 25 and 35 wheat varieties were moderately resistant to P. thornei and P. neglectus, respectively. In total, 17 lines exhibiting multiple resistance reactions to both nematodes were in the same group with the check lines (P<0.05). The identified resistant wheat accessions showed improved levels of RLN resistance over current parents and could serve as an excellent genetic pool to be used in an efficient Turkish wheat breeding programme.Tubitak Project [112 O 565]This publication was supported by Tubitak Project number 112 O 565. The authors thank Prof. Dr. Hakan Ozkan (University of Cukurova) for selecting and supplying the Emmer wheats and Turkish varieties used in the study

<i>Xenorhabdus</i> and <i>Photorhabdus</i> Bacteria as Potential Candidates for the Control of <i>Culex pipiens</i> L. (Diptera: Culicidae), the Principal Vector of West Nile Virus and Lymphatic Filariasis

Vector-borne diseases pose a severe threat to human and animal health. Culex pipiens L. (Diptera: Culicidae) is a widespread mosquito species and serves as a vector for the transmission of infectious diseases such as West Nile disease and Lymphatic Filariasis. Synthetic insecticides have been the prime control method for many years to suppress Cx. pipiens populations. However, recently, the use of insecticides has begun to be questioned due to the detrimental impact on human health and the natural environment. Therefore, many authorities urge the development of eco-friendly control methods that are nontoxic to humans. The bacterial associates [Xenorhabdus and Photorhabdus spp. (Enterobacterales: Morganellaceae)] of entomopathogenic nematodes (EPNs) (Sterinernema spp. and Heterorhabditis spp.) (Rhabditida: Heterorhabditidae and Steinernematidae) are one of the green approaches to combat a variety of insect pests. In the present study, the mosquitocidal activity of the cell-free supernatants and cell suspension (4 × 107 cells mL−1) of four different symbiotic bacteria (Xenorhabdus nematophila, X. bovienii, X. budapestensis, and P. luminescens subsp. kayaii) was assessed against different development stages of Cx. pipiens (The 1st/2nd and 3rd/4th instar larvae and pupa) under laboratory conditions. The bacterial symbionts were able to kill all the development stages with varying levels of mortality. The 1st/2nd instar larvae exhibited the highest susceptibility to the cell-free supernatants and cell suspensions of symbiotic bacteria and the efficacy of the cell-free supernatants and cell suspensions gradually declined with increasing phases of growth. The highest effectiveness was achieved by the X. bovienii KCS-4S strain inducing 95% mortality to the 1st/2nd instar larvae. The results indicate that tested bacterial symbionts have great potential as an eco-friendly alternative to insecticides

The efficacy of fosthiazate, fluopyram, and paecilomyces lilacinus against field population of globodera rostochiensis

The potato cyst nematode, Globodera rostochiensis, is a major potato pest throughout the world. Despite the environmental concerns associated with the use of chemical nematicides, they remain essential for integrated management programs, especially when resistant varieties are lacking. This study investigated fosthiazate efficacy to control G. rostochiensis in potato in comparison to fluopyram and the biological control agent Paecilomyces lilacinus strain PL1. Two independent trials were carried out at fields in Ödemiş and Bozdağ Districts, İzmir Province, Turkey. All treatments reduced densities of G. rostochiensis in roots and soil compared to the non-treated controls. All pesticides consistently decreased the reproduction factor (Rf = final population density/initial population density) values of G. rostochiensis compared to the non-treated controls in Ödemiş and Bozdağ. However, fosthiazate and fluopyram were more effective than the biological agent. Fosthiazate, fluopyram, and P. lilacinus strain PL1 applications increased potato yields in Ödemiş and Bozdağ by 21-34% and 20-31%, respectively, compared to the control. In conclusion, the application of fosthiazate and fluopyram provided a higher level of protection against G. rostochiensis and should be considered an alternative and integrative option in nematode management programs