Wheat Yellow Rust Disease Infection Type Classification Using Texture Features

Wheat is a staple crop of Pakistan that covers almost 40% of the cultivated land and contributes almost 3% in the overall Gross Domestic Product (GDP) of Pakistan. However, due to increasing seasonal variation, it was observed that wheat is majorly affected by rust disease, particularly in rain-fed areas. Rust is considered the most harmful fungal disease for wheat, which can cause reductions of 20–30% in wheat yield. Its capability to spread rapidly over time has made its management most challenging, becoming a major threat to food security. In order to counter this threat, precise detection of wheat rust and its infection types is important for minimizing yield losses. For this purpose, we have proposed a framework for classifying wheat yellow rust infection types using machine learning techniques. First, an image dataset of different yellow rust infections was collected using mobile cameras. Six Gray Level Co-occurrence Matrix (GLCM) texture features and four Local Binary Patterns (LBP) texture features were extracted from grayscale images of the collected dataset. In order to classify wheat yellow rust disease into its three classes (healthy, resistant, and susceptible), Decision Tree, Random Forest, Light Gradient Boosting Machine (LightGBM), Extreme Gradient Boosting (XGBoost), and CatBoost were used with (i) GLCM, (ii) LBP, and (iii) combined GLCM-LBP texture features. The results indicate that CatBoost outperformed on GLCM texture features with an accuracy of 92.30%. This accuracy can be further improved by scaling up the dataset and applying deep learning models. The development of the proposed study could be useful for the agricultural community for the early detection of wheat yellow rust infection and assist in taking remedial measures to contain crop yield.

Monitoring of diseases in crops of sunflower varieties bred at VNIIMK

We observed the diseases in crops of oil and confectionary sunflower in the environments of the central zone of the Krasnodar region in 2018–2020. There are prevailed in crops: bacterial diseases (Xanhomonas, Pseudomonas, Pectobacterium, Rhizobium), dry rot (Rhizopus Ehrenb.), rust (Puccinia helianthi Schw.) and Alternaria blight (Alternaria Nees.). The strongest bacterial blight was observed on confectionary sunflower varieties (up to 72.5%) in 2020. Frequency of dry rot varied depending on the weather conditions of a year: on oil sunflower varieties from 10.0 to 64.0%, on confectionary varieties – from 4.5 to 55%. In recent years rust infection is increased significantly. Frequency of this disease varied from 10 to 64.8% on confectionary sunflower varieties. Rust prevalence on oil sunflower varieties is from 0 to 17.5%. Alternaria blight infection was more on confectionary varieties Karavan (40%) and Conditer (42.5%). Prevalence of the dangerous quarantine disease phomopsis (Phomopsis helianthi Munt.-Cvet.) was insufficient in the years of the research and varied from 0 to 3.7% at the level of infection intensiveness of sunflower plants 0–4 scores due to 4-score scale.

The branched-chain amino acid aminotransferase TaBCAT1 modulates amino acid metabolism and positively regulates wheat rust susceptibility

Plant pathogens suppress defense responses to evade recognition and promote successful colonization. Although identifying the genes essential for pathogen ingress has traditionally relied on screening mutant populations, the post-genomic era provides an opportunity to develop novel approaches that accelerate identification. Here, RNA-seq analysis of 68 pathogen-infected bread wheat (Triticum aestivum) varieties, including three (Oakley, Solstice and Santiago) with variable levels of susceptibility, uncovered a branched-chain amino acid aminotransferase (termed TaBCAT1) as a positive regulator of wheat rust susceptibility. We show that TaBCAT1 is required for yellow and stem rust infection and likely functions in branched-chain amino acid (BCAA) metabolism, as TaBCAT1 disruption mutants had elevated BCAA levels. TaBCAT1 mutants also exhibited increased levels of salicylic acid (SA) and enhanced expression of associated defense genes, indicating that BCAA regulation, via TaBCAT1, has a key role in SA-dependent defense activation. We also identified an association between the levels of BCAAs and resistance to yellow rust infection in wheat. These findings provide insight into SA-mediated defense responses in wheat and highlight the role of BCAA metabolism in the defense response. Furthermore, TaBCAT1 could be manipulated to potentially provide resistance to two of the most economically damaging diseases of wheat worldwide.

Differential Gene Expression Analysis of Wheat Breeding Lines Reveal Molecular Insights in Yellow Rust Resistance under Field Conditions

The evolution of pathogens in the changing climate raises new challenges for wheat production. Yellow rust is one of the major wheat diseases worldwide, leading to an increased use of fungicides to prevent significant yield losses. The enhancement of the resistance potential of wheat cultivars is a necessary and environmentally friendly solution for sustainable wheat production. In this study, we aimed to identify the differentially expressed genes induced upon yellow rust infection in the field. Reference and de novo based transcriptome analysis was performed among the resistant and susceptible lines of a bi-parental population to study the global transcriptome changes in contrasting wheat genotypes. Based on the analysis, the de novo transcriptome analysis approach was found to be more supportive for field studies. Expression profiles, gene ontology, KEGG pathway analysis and enrichment studies indicated the relation between differentially expressed genes of wheat and yellow rust infection. The h0igh expression of genes related to non-race specific resistance along with pathogen-specific resistance might be a reason for the better resistance ability of a resistant wheat genotype in the field. The targeted metagenomic analysis of wheat samples revealed that Puccinia striiformis tritici was the most dominant pathogen along with other pathogens on the collected leaf material and validating the disease scoring carried out in the field and transcriptomics analyses.

Puccinia xinyuanensis sp. nov., the causal agent of rust on wild tulip (Tulipa iliensis) in China

A severe rust infection was observed on leaves of Tulipa iliensis in the desert regions of the Tianshan Mountains in China. The pathogen is similar to P. tulipae, a microcyclic rust of several Tulipa species, but differs in larger teliospores, and in the production of spermogonia and aecia. Herein, we describe Puccinia xinyuanensis sp. nov., an autoecious demicyclic rust of Tulipa iliensis. This is the first known rust on this host.