Plant Extracts Inducing Enzyme Activity in Grains Against Loose Smut Disease

This study investigated the role of endogenous Palestinian plant extracts in inducing wheat and barley resistance systems against loose smut disease with the aim to alternate the chemical pest control with natural fungicides. Twenty indigenous herbal plant extracts and essential oils were assessed for their biological and antifungal properties against Ustilago tritici and Ustilago nuda. Their potential role in inducing resistance pathways was studied on four different cultivars of wheat and barley. Two common enzyme indicators – guaiacol peroxidase (POX) and polyphenol oxidase (PPO) – are expressed in plants only after physical or chemical induction. The antifungal activity of the plant extracts was investigated in vitro. Totally 70 % of the plant extracts showed antifungal activity against Ustilago tritici and Ustilago nuda. Coridothyme extracts ranked first (61 %) in the fungal growth inhibition, followed by varthemia, salvia, ambrosia, artemisia, and lemon thyme. Some plant extracts significantly increased the POX and PPO effect compared to control for all the wheat and barley cultivars tested. The study revealed that oregano, clove or lavender and pomegranate, common yarrow or chamomile oil effectively induced the resistance indicator enzymes in wheat and barley.

AAC Magnet Canada Western Red Spring wheat

AAC Magnet (BW1045) is an awned, hollow-stemmed, high-yielding Canada Western Red Spring (CWRS) wheat adapted to growing conditions in the Canadian Prairies. AAC Magnet was 5% higher yielding than Glenn and yielded 2% more than Carberry, a popular CWRS wheat variety across the Canadian Prairies. AAC Magnet matured 2 d earlier than Carberry and a day later than Unity, the earliest maturing check. AAC Magnet had the same height as Glenn and was shorter with better stem strength compared with Unity. AAC Magnet had better lodging scores compared with Unity. Over the 3 yr of testing (2015–2017), the test weight of AAC Magnet was slightly lower than the lowest checks, whereas the 1000-kernel weight of AAC Magnet was higher than all of the checks. The grain protein content of AAC Magnet was 0.3% lower than Carberry. AAC Magnet was rated moderately resistant to Fusarium head blight (Fusarium graminearum Schwabe), resistant to leaf rust (Puccinia triticina Erikss.) and stem rust (Puccinia graminis Pers. f. sp. tritici Erikss. & E. Henn). AAC Magnet was moderately susceptible/susceptible to resistant to the Ug99 family of stem rusts, resistant to loose smut [Ustilago tritici (Pers.) Rostr.], intermediately resistant to stripe rust (Puccinia striiformis Westend.), susceptible to common bunt [Tilletia caries (DC.) Tul. & C. Tul.], and moderately susceptible to leaf spot complex. AAC Magnet was susceptible to orange wheat blossom midge (Sitodiplosis mosellana Géhin). Based on the milling and baking performance over 3 yr (2015–2017) evaluated by the Grain Research Laboratory, Canadian Grain Commission, AAC Magnet was classified as CWRS wheat.

qPCR and loop mediated isothermal amplification for rapid detection of Ustilago tritici

Loose smut of wheat caused by the basidiomycete fungus Ustilago tritici, a seed-borne disease, is difficult to control because of the expanse of wheat planting area and difficulty in pathogen detection. In this study, real-time fluorescence quantitative PCR (qPCR) and loop-mediated isothermal amplification (LAMP) assays are used to rapidly amplify the DNA of U. tritici. Five pairs of primers for qPCR and two series primers for LAMP were designed. Primarily, the specificity of the primer was assessed by using genomic DNA of U. tritici, Fusarium graminearum, Blumeria graminis, Rhizoctonia cerealis, Puccinia striiformis, Bipolaris sorokiniana, and Alternaria solani as templates. Further, the amplification systems were optimized. Finally, the sensitivity of qPCR and LAMP assays were evaluated. The results showed that the primer Y-430 F/R, Y-307 F/R, Y-755 F/R, and Y-139 F/R for qPCR and primers L-139 and L-988 for LAMP could be used for U. tritici detection. In the sensitivity test, the detection limit of qPCR assay was identified as 10 pg μL−1 of genomic DNA, the detection limit for LAMP assay was 100 fg μL−1. We successfully performed qPCR and LAMP assays on wheat loose smut wheat samples. This paper establishes two methods for U. tritici detection, which can be used for diagnosis of wheat loose smut in the laboratory and in the field.

Identification of Tilletia foetida, Ustilago tritici, and Urocystis tritici Based on Near-Infrared Spectroscopy

Identifying plant pathogens for disease diagnosis and disease control strategy making is of great significance. In this study, based on near-infrared spectroscopy, a method for identifying three kinds of pathogens causing wheat smuts, including Tilletia foetida, Ustilago tritici, and Urocystis tritici, was investigated. Based on the acquired near-infrared spectral data of the teliospore samples of the three pathogens, pathogen identification models were built in different spectral regions using distinguished partial least squares (DPLS), backpropagation neural network (BPNN), and support vector machine (SVM). Satisfactory identification results were achieved using the DPLS, BPNN, and SVM models built in each of the 22 spectral regions. By contrast, the modeling effects of DPLS and SVM were better than those of BPNN. The modeling ratio of the training set to the testing set affected the identification results of the BPNN models more than those obtained using the DPLS and SVM models. In this study, a rapid, accurate, and nondestructive method was provided for plant pathogen identification, and some basis was provided for disease diagnosis, pathogen monitoring, and disease control. Moreover, some methodological references and supports were provided for identification of quarantine wheat smut fungi in plant quarantine.

The qPCR and loop mediated isothermal amplification for rapid detection of Ustilago tritici

Wheat loose smut caused by Ustilago tritici a seed-borne disease, is difficult to control due to the expansion of wheat planting area and difficulty of pathogen detection. In this study, real-time fluorescence quantitative PCR (qPCR) and loop-mediated isothermal amplification (LAMP) assays were used to rapidly amplify the DNA of U. tritici. Five pairs primers for qPCR and two series primers for LAMP were designed. Firstly, the specify of primers were carried out by using the DNAs of U. tritici, Fusarium graminearum, Blumeria graminis, Rhizoctonia cerealis, Puccinia striiformis, Bipolaris sorokiniana, and Alternaria solani as templates. Then the amplification systems are optimized. Finally, the sensitivity of qPCR and LAMP assays were quantified. The results show that using the primers pairs Y430F/R, Y307F/R, Y755F/R and Y139F/R for qPCR, primers L-139 and L-988 for LAMP assay could be used for U. tritici detection. In the sensitivity test, the detection limit of qPCR assay is 10 pg μL-1 of genomic DNA, the detection limit of LAMP assay is 100 fg μL -1 . We successfully performed qPCR and LAMP assays on two wheat loose smut wheat samples, and confirmed sequenced U. tritici infection by subsequently sequencing. This paper established two methods for U. tritici detection, which could be used for wheat loose smut diagnose in lab and field.