Advances in understanding the biology and epidemiology of rust diseases of cereals

2021 ◽  
pp. 15-38
Author(s):  
Vanessa Bueno-Sancho ◽  
◽  
Clare M. Lewis ◽  
Diane G. O. Saunders ◽  
◽  
...  

Rust fungi (order: Pucciniales) constitute the largest group of plant parasitic fungi and include many species of agricultural importance. This includes the three wheat rust fungi (Puccinia graminis f. sp. tritici, Puccinia striiformis f. sp. tritici and Puccinia triticina) that have posed a threat to crop production throughout history. This chapter provides an overview of the wheat rust pathogen lifecycle that has been critical to the design of effective disease management strategies and discusses recent integration of basic biological knowledge and genomic-led tools within an epidemiological framework. Furthermore, we include a case study on the “field pathogenomics” technique, illustrating the value of genomic-based tools in disease surveillance activities. Bringing together advances in understanding basic pathogen biology, developments in modelling for disease forecasting and identification, alongside genomic-led advances in surveillance and resistance gene cloning, holds great promise for curtailing the threat of these notorious pathogens.

2017 ◽  
Vol 27 (5) ◽  
pp. 299-305 ◽  
Author(s):  
Adam Kuzdraliński ◽  
Anna Kot ◽  
Hubert Szczerba ◽  
Agnieszka Ostrowska ◽  
Michał Nowak ◽  
...  

The species <i>Puccinia triticina</i> (Pt) and <i>Puccinia striiformis</i> f. sp. <i>tritici </i>(Pst) are devastating cereal pathogens that cause leaf and stripe rust diseases. We developed PCR assays for the species-specific detection of Pt and Pst, 2 biological agents that cause wheat rust disease. For each pathogen, we validated 3 primer sets that target the second largest subunits of the RNA polymerase II (<i>rpb2</i>) and β-tubulin 1 (<i>tub1</i>) genes. The specificities of the primers were verified using naturally infected plant materials with visual symptoms of disease. All primer sets amplified a single DNA fragment of the expected length. The primer sets LidPr15/16, LidPr1/2, and LidPs13/14 were able to detect small amounts of pure fungal DNA with sensitivities of 0.1, 1, and 10 pg/μL, respectively. A sufficient detection limit (1 pg/μL to 5 ng/μL) was observed for all assays when the sensitivity test was performed with host plant DNA. The study also evaluated the simultaneous detection of both rust pathogens, and the multiplex PCR assay generated amplicons of 240 and 144 bp in length for Pts (LidPs9/10) and Pt (LidPr1/2), respectively.


2020 ◽  
Vol 116 (11/12) ◽  
Author(s):  
Zacharias A. Pretorius van der Walt ◽  
Renée Prins ◽  
Elsabet Wessels ◽  
Cornel M. Bender ◽  
Botma Visser ◽  
...  

Rust diseases, although seasonal, have been severe constraints in wheat production in South Africa for almost 300 years. Rust research gained momentum with the institution of annual surveys in the 1980s, followed by race identification, an understanding of rust epidemiology, and eventually a focused collaboration amongst pathologists, breeders and geneticists. Diversity in South African populations of Puccinia triticina, P. graminis f. sp. tritici and P. striiformis f. sp. tritici has been described and isolates are available to accurately phenotype wheat germplasm and study pathogen populations at national, regional and global levels. Sources of resistance have been, and still are, methodically analysed and molecular marker systems were developed to incorporate, stack and verify complex resistance gene combinations in breeding lines and cultivars. Vigilance, capacity, new technologies, collaboration and sustained funding are critical for maintaining and improving the current research impetus for future management of these important diseases.


Author(s):  
G. V. Volkova ◽  
O. A. Kudinova ◽  
O. F. Vaganova

Currently, more than 70 wheat rust resistance genes are known, but few of them are effective. The purpose of this work is to screen lines of Lr gene carriers for resistance to leaf rust under conditions of the North Caucasus region. Investigations were carried out in 2016-2018 at the infectious site of VNIIBZR. Research material was 49 near isogenic lines of winter wheat cultivar Thatcher. Infectious material was the combined populations of P. triticina, obtained as a result of route surveys of industrial and breeding crops of winter wheat in the areas of the Krasnodar, Stavropol Territories and the Rostov Region, conducted in 2016-2018. According to the assessment, the genes are ranked as follows: - highly efficient genes (plants with no signs of damage): Lr9, Lr42, Lr43 + 24 and Lr50; effective (1R-5R) Lr genes: 19, 24, 29, 36, 37, 38, 45, 47; moderately effective (10MR-20MR) Lr genes: 17, 18, 21, 22a, 28, 32, 41, 52. The remaining Lr-lines were susceptible to P. triticina (25 MR - 90S) to varying degrees. Highly efficient and effective genes Lr9, Lr19, Lr24, Lr29, Lr38, Lr42, Lr43 + 24, Lr47 and Lr50 showed resistance in the seedling phase and can be recommended for inclusion in breeding programs to protect wheat from leaf rust in different phases of plant ontogenesis in the North Caucasus region.


2021 ◽  
Vol 10 (5) ◽  
pp. 309
Author(s):  
Zixu Wang ◽  
Chenwei Nie ◽  
Hongwu Wang ◽  
Yong Ao ◽  
Xiuliang Jin ◽  
...  

Maize (Zea mays L.), one of the most important agricultural crops in the world, which can be devastated by lodging, which can strike maize during its growing season. Maize lodging affects not only the yield but also the quality of its kernels. The identification of lodging is helpful to evaluate losses due to natural disasters, to screen lodging-resistant crop varieties, and to optimize field-management strategies. The accurate detection of crop lodging is inseparable from the accurate determination of the degree of lodging, which helps improve field management in the crop-production process. An approach was developed that fuses supervised and object-oriented classifications on spectrum, texture, and canopy structure data to determine the degree of lodging with high precision. The results showed that, combined with the original image, the change of the digital surface model, and texture features, the overall accuracy of the object-oriented classification method using random forest classifier was the best, which was 86.96% (kappa coefficient was 0.79). The best pixel-level supervised classification of the degree of maize lodging was 78.26% (kappa coefficient was 0.6). Based on the spatial distribution of degree of lodging as a function of crop variety, sowing date, densities, and different nitrogen treatments, this work determines how feature factors affect the degree of lodging. These results allow us to rapidly determine the degree of lodging of field maize, determine the optimal sowing date, optimal density and optimal fertilization method in field production.


Author(s):  
Marianna Fenzi ◽  
Paul Rogé ◽  
Angel Cruz-Estrada ◽  
John Tuxill ◽  
Devra Jarvis

AbstractLocal seed systems remain the fundamental source of seeds for many crops in developing countries. Climate resilience for small holder farmers continues to depend largely on locally available seeds of traditional crop varieties. High rainfall events can have as significant an impact on crop production as increased temperatures and drought. This article analyzes the dynamics of maize diversity over 3 years in a farming community of Yucatán state, Mexico, where elevated levels of precipitation forced farmers in 2012 to reduce maize diversity in their plots. We study how farmers maintained their agroecosystem resilience through seed networks, examining the drivers influencing maize diversity and seed provisioning in the year preceding and following the 2012 climatic disturbance (2011–2013). We found that, under these challenging circumstances, farmers focused their efforts on their most reliable landraces, disregarding hybrids. We show that farmers were able to recover and restore the diversity usually cultivated in the community in the year following the critical climate event. The maize dynamic assessed in this study demonstrates the importance of community level conservation of crop diversity. Understanding farmer management strategies of agrobiodiversity, especially during a challenging climatic period, is necessary to promote a more tailored response to climate change in traditional farming systems.


2017 ◽  
Vol 2 ◽  
pp. 31
Author(s):  
Salar Farhangi Abriz

<p>Over dose using of herbicides is one of the major problems in crops and horticulture productions. Human food safety and economical production of agricultural products are the main target of new agronomy and plant scientists. Integrative management is one of the new programs for reducing herbicide doses in agriculture. This program includes many physiological and physicochemical methods for controlling herbicide uses in farms and orchards. This article explain some of these methods such as using surfactants, water quality in spraying, using magnetic fields, controlling the nitrogen content of soil, using a suitable formulation and powerful cultivars and genotypes in agriculture and the effects of this reduction in herbicide doses on plants behavior and weeds controlling. According to this method integrative management can be beneficial in crop production and farmers must be using of this management method in their farms. </p>


2014 ◽  
Vol 11 (2) ◽  
pp. 803-812
Author(s):  
Baghdad Science Journal

General survey for wheat rust diseases in Iraqi fields was done during the seasons of 2010, 2011 and 2012. The survey covered different fields in southern, middle and northern regions. Results of the first season indicated that most of Iraqi cultivars such as Tmmoze2, IPA 99 and Mexipak showed different types of susceptibility to both yellow and leaf rust infection. Disease severity increased when the conditions were favorable for infections with using susceptible cultivars. The severity of leaf rust was less in the north region comparing with the middle and south regions. Most of the introduced cultivars such as Sham6 and Cimmyto showed susceptible reaction to yellow and leaf rust. Yellow rust was in epiphytotic form at the Iraqi-Syrian-Turkish triangle where the disease severity was 100%. Low disease severity of stem rust was observed on some cultivars (1-5%), except for the cultivar Mexipak which showed 40%S in Najaf. Rusts at season of 2011 were restricted mostly in Baghdad and the yellow rust was dominant. The AUDPC of 15 wheat cultivars showed that Sawa and Sali were highly susceptible to the three types of rusts while Babil113 and Tamoze2 were resistant. No rusts were detected at season 2012.


2020 ◽  
Vol 2 (4) ◽  
Author(s):  
Sahrish Khan ◽  
Abdul Waris

Due to increase in the population which is estimated that the human papulation will increased 9.7 billion in 2050. There is also increase the demands of the food productions. That’s why there is need to solve the problems regarding to the production of the food. Major problem of the food production is the shortage of the land due to the low and bad soil structure and quality of the soil. Soil erosion is one of the main issue which is caused  due to the used of different chemicals, pesticides and fertilizers which are mainly used for the  plant growth and protection but they are the main reasons of the production of the pollution in the soil. There is need of the different new technology for the improvement of the soil structure, quality, its fertility and decontamination of pollution from the soil which are eco-friendly to the environment and have no adverse effect. In this study the role of the different techniques in which genetic engineering, Nano technologies, soil and crop management strategies, integrated pest control management strategies, sustainable remediation techniques, microbial management strategies and the different management stairgates. All these techniques aim to the production of the plants and microbes which are effective against plant disease management. The aim of the use nano agrochemicals and nano sensors for sensing environmental and pathogen conditions against disease management. The aim of the paper to provide the production of the disease resistance plant and the provide balanced nutrients supplements to the soil for the improvement of the soil condition and its fertility. These techniques have economic importance due to the use of the nano agrochemicals which are low cost and have effective and reduce the use of the chemicals substances which have negative effect on the  soil fertility.. There are sustainable remediations techniques also discussed which are used for the decontamination of the soil pollution. In this study the main focus on the improve and increase soil fertility which enhance the growth of the plants as well the production of the crop production. The production of the stress and degradation resistance microbes which is important factor for the protection of the soil from degradation or contamination. All the techniques which are used in this paper have no adverse effect they are helpful in the tolerance of the stress conditions.


1986 ◽  
Vol 41 (5-6) ◽  
pp. 559-563 ◽  
Author(s):  
Carlos A. Ocampo ◽  
Bruno Moerschbacher ◽  
Hans J. Grambow

The hypersensitive reaction in incompatible wheat-rust interactions is characterized by an increase in lipoxygenase activity detectable as early as 28 h after penetration of the pathogen. In contrast, lipoxygenase activity in the compatible interaction did not increase until the onset of sporulation.Lipoxygenase activity also increased following treatment of wheat leaves with an elicitor fraction from germ tubes of Puccinia graminis tritici.


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