Special Issue "The Impact of Plant Disease on Food Security"

Guest Editor
Prof. Dr. David Guest
Faculty of Agriculture, Food and Natural Resources, The University of Sydney, Biomedical Building C81, 1 Central Avenue, Australia Technology Park, Eveleigh, NSW 2015, Australia
Website: http://sydney.edu.au/agriculture/staff/find_staff_member/staff_profiles/david_guest.shtml
E-Mail: david.guest@sydney.edu.au
Phone: +61 2 8627 1026
Interests: plant-pathogen interactions; plant defence; phytoalexins, hypersensitive cell death; Phytophthora; integrated disease management

Dear Colleagues,

As agriculture struggles to support the rapidly growing global population, plant disease reduces the production and quality of food, fibre and biofuel crops. Losses may be catastrophic or chronic, but on average account for 42% of the production of the six most important food crops. Losses due to postharvest disease can be disastrous, especially when farms are a long way from markets and infrastructure and supply chain practices are poor. Many postharvest pathogens also produce toxins that create serious health problems for consumers.
Farmers spend billions of dollars are on disease management, often without adequate technical support, resulting in poor disease control, pollution and harmful results. In addition, plant disease can devastate natural ecosystems, compounding environmental problems caused by habitat loss and poor land management.
Crop losses tend to be greatest in tropical countries where environmental conditions are particularly favourable, incomes are low and knowledge and investments in crop health management are minimal. Disease losses can mean that communities become dependent on imported foods, often replacing a balanced diet with processed foods that create further health problems.
Plant breeders have very successfully increased potential crop yields, however the impacts of crop breeding for resource-poor farmers have been disappointing. Much greater emphasis is required to address reasons for the gap between potential and actual yields achieved by farmers, and research that is focussed on narrowing this gap.
This issue is focused on research aimed at improving food security by reducing crop losses, particularly for low-income farmers. Manuscripts are invited that describe research into improving food security by reducing yield losses. Such research may include plant pathology, agronomy, entomology, weed science, farm management, improving resilience to abiotic constraints, postharvest handling, food safety, improved market access, the role of biotechnology, technology transfer, extension, education, policy and any other related topics.

Prof. Dr. David Guest
Guest Editor

Submission

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• Plant disease, Crop losses
• Food security
• Postharvest disease, postharvest pathogens, toxins
• Plant pathology, agronomy, entomology, weed science, farm management
• Resilience to abiotic constraints, postharvest handling
• Tropical countries, low-income farmers
• Market access, technology transfer, education, policy

Title: Nonstop Selection for High and Stable Crop Yield by two Prognostic Equations to Reduce Yield Losses
Author: Dionysia A. Fasoula
Affiliations: Agricultural Research Officer A, Plant Breeding and Molecular Genetics, Agricultural Research Institute, P.O. Box 22016, 1516 Nicosia, Cyprus
Abstract: Yield losses that occur at the field level, whether by plant diseases or abiotic stresses, reveal reduced stability of the crop yield potential. The paper argues that stability of crop yield potential is a trait with a clear genetic component which can be successfully selected for at the single-plant level through a systematic breeding strategy and incorporated into high-yielding finished cultivars. Two novel selection equations with prognostic power are presented, capable to objectively phenotype and evaluate individual plants in real field conditions in the absence of the masking effects of interplant competition and soil heterogeneity. The equations predict performance at the crop stand through the key concept of coefficient of homeostasis and are equally useful for early generation selection and for nonstop selection within finished cultivars in order to gradually and continuously incorporate plant adaptive responses. Exploitation of adaptive responses acquires particular importance in view of the climate change effects on crop productivity and the continuously changing biotic or abiotic micro-environments. Cotton is used as a case study to highlight the potential of nonstop selection for increasing crop yield and for gradual development of disease resistance. In addition, the paper envisions and proposes the formation of international networks of researchers focusing on specific diseases as for example, the wheat root-rot or the cotton Verticillium wilt that will concurrently use the proposed strategy in their respective environments to select for resistant genotypes, while gaining a deeper understanding of the nature of the genetic and epigenetic changes at the phenotypic and genomic levels.

Title: Taro Leaf Blight—A Threat to Global Food Security
Authors: D. Singh, D. Hunter, T. Iosefa, T. Okpul, R. Kapila, V. Lebot, M. Taylor and G. Jackson
Affiliation: Plant Breeding Institute, Faculty of Agriculture, Food & Natural Resources, THE UNIVERSITY OF SYDNEY, 107 Cobbitty Rd, Cobbitty, NSW, 2570, Australia
Abstract: Taro (Colocasia esculenta) a clonally propagated aroid, is a food crop of great importance to global food security. All plant parts are utilized, corms are baked, roasted, or boiled, leaves are frequently eaten as a vegetable and represent an important source of vitamins. Today, taro has spread throughout the world and is now an important crop in Asia, the Pacific, Africa and the Caribbean. Taro leaf blight (caused by the fungus Phytophthora colocasiae) is a disease of major importance in many regions of the world where taro is grown. Serious outbreaks of taro leaf blight in Samoa in 1993 and in the last few years in Nigeria and Ghana continue to decimate fields cultivated with taro negatively impacting the livelihoods and food security of small farmers and rural communities dependent on the crop. The spread of the disease to new geographical areas continues to pose a major threat to neighbouring countries and taro growing regions still free from the disease. Past research, particularly in the Pacific, has demonstrated that management measures such as chemical and cultural control are largely ineffective and that breeding for disease resistance is the most sustainable approach to manage the disease. Unfortunately, taro remains a seriously neglected and underutilized crop and genetic improvement and the management of production constraints has attracted little interest from the international scientific community. Recognizing these limitations two research networks, TaroGen and TANSAO, have made excellent progress in taro improvement identifying good resistance to taro leaf blight through enhanced utilization of taro genetic resources and breeding involving both researchers and farmers. This paper provides an overview of the disease, its origin, distribution, biology, epidemiology, management and global impact. The paper will largely focus on breeding strategies to address the disease including challenges, opportunities and constraints and how these breeding experiences and outputs can be scaled up to other geographical areas where the disease has been recently introduced or under threat of introduction.

Title: Photosynthesis and Yellow Vine Syndrome of American Cranberry
Author: Harvey J. M. Hou
Affiliation: Department of Physical Sciences, Alabama State University, 915 South Jackson Street, Montgomery, Alabama 36104, USA; E-Mail: hhou@alasu.edu; Tel.: +1 334 229-5121; Fax: +1 334 229-5409
Abstract: The American cranberry (Vaccinium macrocapron Ait.) contains rich antioxidants and has significant health benefits in fighting a variety of human diseases. In the past ten years, cranberry growers have reported yellow vine syndrome, which is associated with the reduced photosynthetic performance, in the cranberry bogs. However, the molecular mechanism for developing the syndrome is unknown. Complete understanding of the mechanisms of yellow vine syndrome development may offer an opportunity to minimize its effect. In this review, the recent advances in probing the mechanism for the formation of yellow vine syndrome and possible solutions are summarized. Potential limitations and future efforts are also assessed.

Title: Use of Bio-Fungicides in Controlling Plant Diseases to Improve Food Security
Authors: Antonieta De Cal, Inmaculada Larena, Belén Guijarro, Pilar Sabuquillo, Gema Vázquez and Paloma Melgarejo *
Affiliation: Departamento de protección Vegetal, Carretera de la Coruña km. 7. 28040 Madrid, Spain.
Abstract: Biological control of fungal plant pathogens can improve food security by reducing crop losses, particularly for low-income farmers. In the narrowest sense, biocontrol involves suppressing plant pathogens with other organisms. However, the interrelationships of many environmental variables can result in multiple interactions among organisms and their environment, several of which might contribute to effective biological control. Here, we use the term biological control in the broader sense as we describe the current status of research on tomato wilt and brown rot biocontrol, identified difficulties and conditions for field success of biocontrol, and commercial development of three biological agents.

Type of Paper: Article
Title: Purification and Phytotoxic Analysis of Botrytis cinerea Virulence Factors: New Avenues for Crop Protection
Authors: Subodh Rathi and Robert L. McFeeters ^*
Affiliation: University of Alabama in Huntsville, Department of Biological Sciences, 301 Sparkman Drive, Huntsville, AL 35899, USA; E-Mails: sgr001@uah.edu (S.R.); robert.mcfeeters@uah.edu (R.L.M.)
Abstract: Botrytis cinerea is a necrotrophic fungus infecting over 200 species of plants world-wide. This highly adaptable pathogen can afflict agricultural products from seed to storage. Small protein virulence factors secreted during the infection play an important role in initiation and spread of disease. Proteomic analysis identified a number of potential target proteins possibly involved in plant-pathogen interactions. One target, BcSnod1, was found to be abundantly expressed upon exposure to media containing strawberry extract. From sequence similarity, BcSnod2 was also identified and both were categorized as members of the Ceratoplatanin family of small proteins. Recombinant BcSnod1 was shown to have a phytotoxic effect and play an important role in pathogenecity while the role of BcSnod2 remains less clear. Both bacterial and yeast production systems are reported, though the bacterial protein is not as active and mostly unfolded relative to that made in yeast. Compared to BcSnod1, recombinant bacterial BcSnod2 shows similar, but delayed phytotoxicity on tomato leaves. Further studies of these critical virulence factors promise to provide potential new avenues for crop protection.

Type of Paper: Review
Title: New Antifungal Approaches to the Recurring Threat of Botrytis cinerea
Authors: Hana McFeeters and Robert L. McFeeters ^*
Affiliation: University of Alabama in Huntsville, Department of Chemistry, 301 Sparkman Drive, Huntsville, AL 35899, USA; E-Mails: hk0003@uah.edu (H.M); robert.mcfeeters@uah.edu (R.L.M.)
Abstract: Botrytis cinerea is a pathogenic fungus that has tremendous adverse impact on world agriculture. With susceptibility from seed to storage, the highly adaptive nature of this fungus under selective pressure, and ability to thrive at lower temperatures, B. cinerea is a formidable challenge to agribusiness. Technological advances in genetics, biochemistry, and biotechnology are providing new and unparalleled possibilities for treatment and management. With the resulting explosion of novel antifungal agents, it is difficult to keep abreast. This review not only catalogs and summarizes recent antifungal discoveries that target B. cinerea (though many target other pathogenic fungi as well), but tries to give the reader a feel for how expansive the new possibilities are. Regrettably, there is simply too much for any single manuscript. Therefore this review focuses on natural products and protein/peptide antifungals. For completeness, a perspective on emerging antifungal advances that hold potential to significantly impact the botrycide landscape is included.