Plant growth-promoting microorganisms as biocontrol agents of plant diseases: Mechanisms, challenges and future perspectives

Plant diseases and pests are risk factors that threaten global food security. Excessive chemical pesticide applications are commonly used to reduce the effects of plant diseases caused by bacterial and fungal pathogens. A major concern, as we strive toward more sustainable agriculture, is to increase crop yields for the increasing population. Microbial biological control agents (MBCAs) have proved their efficacy to be a green strategy to manage plant diseases, stimulate plant growth and performance, and increase yield. Besides their role in growth enhancement, plant growth-promoting rhizobacteria/fungi (PGPR/PGPF) could suppress plant diseases by producing inhibitory chemicals and inducing immune responses in plants against phytopathogens. As biofertilizers and biopesticides, PGPR and PGPF are considered as feasible, attractive economic approach for sustainable agriculture; thus, resulting in a “win-win” situation. Several PGPR and PGPF strains have been identified as effective BCAs under environmentally controlled conditions. In general, any MBCA must overcome certain challenges before it can be registered or widely utilized to control diseases/pests. Successful MBCAs offer a practical solution to improve greenhouse crop performance with reduced fertilizer inputs and chemical pesticide applications. This current review aims to fill the gap in the current knowledge of plant growth-promoting microorganisms (PGPM), provide attention about the scientific basis for policy development, and recommend further research related to the applications of PGPM used for commercial purposes

Plant growth-promoting root-colonizing bacterial endophytes

The development of an environmentally friendly agricultural system as opposed to conventional methods using chemical fertilizers and pesticides for improved crop productivity is a promising aspect of modern agricultural biotechnology. Current research has focused on using free-living microbes that can colonize the plant endosphere as a means of enhancing crop productivity. In the plant rhizosphere, the complex root matrix facilitates microbe-microbe, microbe-plant, and soil-microbe interactions in establishing microbial communities, which precede endophytic colonization of the plant by some of these microbes. Endophytic microbes play an important role in plant growth promotion, as they employ direct or indirect mechanisms to facilitate plant growth by producing phytohormones and various secondary metabolites. The roles of endophytic microbes in sustaining plant growth under biotic and abiotic stresses through these mechanisms can provide insights into their envisaged putative functions in establishing host plant interactions for maximum use in the agricultural sector as an ecofriendly alternative tool to improve crop yield. In addition, a better understanding of endophytic bacteria functions in agriculture, medicine, biotechnology, and industry may enable scientists to unlock several opportunities by exploring valuable endophytic bioproducts in the recent application as bioinoculants, biostimulants, and environmental safety in pollution control and phytoremediation. Furthermore, the genomic insights into endosphere biology can provide detail structural diversity and functional profiling of endophytic microbiome for possible recommendations in future agriculture as a source of the organic amendment. Hence, this review emphasis on the root-colonizing endophytic bacteria and their importance in modern agricultural biotechnology.National Research Foundation of South Afric

The deployment of intercropping and agroforestry as adaptation to climate change

Food security is threatened by the combined pressures of increasing populations and climate change. Agricultural land is vulnerable to overexploitation and environmental change. Within this review, we identify the role of multiple cropping systems as an adaptation method towards climate change. Intercropping, the relay or simultaneous cultivation of two or more crops, and agroforestry, the incorporation of trees on at least 10% of agricultural land, provides an alternative cropping practice which can provide many advantages over industrial sole cropping. Examples from these systems are given to indicate how multiple cropping can provide increased yield, stability, ecosystem services and societal benefits when adopted. We also discuss instances where multiple cropping systems may be maladaptive or instances where desired benefits may not be achieved. Finally, we highlight the important considerations or constraints limiting the adoption of alternate systems and indicate how modelling approaches can be used to reduce the uncertainty of altering agricultural systems. This review challenges the traditional concept of how to increase industrial crop yields whilst maintaining sustainability. Future research should be aimed at overcoming the constraints limiting adoption of alternative cropping systems to revolutionise global crop production

Symbiotic nitrogen fixation : prospects for enhanced application in tropical agriculture

In addition to their Nitrogen (N2)-fixing capacity legumes are extremely important in human and animal diets, significantly improving household health standards. This book is based on the proceedings of the workshop (“International Workshop on Biological Nitrogen Fixation for Increased Crop Productivity, Enhanced Human Health and Sustained Soil Fertility,” 2002, at ENSAM-INRA, Montpellier, France), takes a holistic approach to harnessing legume Biological Nitrogen Fixation (BNF) technologies, starting from a socioeconomic perspective, and progressing to agronomic and genetic options, bringing together innovative aspects and participatory research strategies

Quality assessment of commercial biofertilisers and the awareness of smallholder farmers in Gauteng Province, South Africa

This study aimed to evaluate commercial biofertiliser quality and awareness amongst smallholder farmers in Gauteng Province, South Africa. Sixty-seven smallholder farmers were interviewed in Gauteng Province by using a survey method, while the physicochemical and microbiological properties of 13 biofertilisers were evaluated using laboratory experiments. The results showed that awareness and use of biofertiliser are very poor, with 96% of the smallholder farmers surveyed not having biofertiliser knowledge. Furthermore, the products lack basic quality parameters: 54% contained no biofertiliser strain while all the products contained microbial contaminants. The pH, moisture content and viable microbial densities were below the acceptable standards for some of the products. Two fungal and 58 bacterial operational taxonomic units were obtained from the 16S rRNA Sanger sequences while 5 791 OTUs were obtained from the Illumina Miseq system. Approximately 40%, 41% and 59% of the isolates were positive for nitrogen-fixation, siderophore production and phosphorous solubilisation. Overall, there is a need to improve awareness amongst farmers and promote good-quality biofertiliser products for increased crop productivity.Environmental SciencesM. Sc. (Environmental Science

Carcinogen

During the last decades, cancer diseases have increased all over the world. The low quality of food and strong pollution of environment are the main prerequisites for carcinogenesis. The main problem for scientists is to find strategy for prevention of cancer diseases. Therefore, the information about the models for studying carcinogenesis and mutagens which appear during cooking, environmental pollutants, and tests for specific detection of carcinogens is particularly important. The book "Carcinogen" is intended for biologists, researchers, students in medical sciences and professionals interested in associated areas

Impact of Trichoderma on the microbiome of wheat crop plants and its biostimulant potential under water stress conditions

Tesis por compendio de publicaciones[ES]La agricultura es uno de los pilares básicos de la sociedad actual, cuyo crecimiento constante demanda un aumento de la producción de los cultivos para asegurar el abastecimiento de toda la población. Sin embargo, todas las predicciones apuntan a que en los próximos años el cambio climático afectará negativamente a la producción de cultivos y la seguridad alimentaria en todo el mundo. El trigo es uno de los cultivos más consumidos a nivel mundial y constituye un alimento base y en muchos casos necesario en la dieta de una gran parte de los seres humanos y también de los animales. Sin embargo, su producción se ve negativamente afectada por los episodios de sequía, cada vez más intensos y frecuentes a causa del cambio climático. En este contexto, la agricultura moderna tiene como desafío conseguir un aumento de la producción agrícola, así como la resiliencia y adaptación de los cultivos a la variación de las condiciones medioambientales. No obstante, las prácticas agrícolas actuales son altamente dependientes del uso de agroquímicos, cuya inadecuada y, en muchos casos, indiscriminada aplicación está causando problemas de contaminación y pérdida de la biodiversidad del suelo. En los últimos años, el uso de microorganismos como bioestimulantes y biofertilizantes ha surgido como una alternativa prometedora para sustituir o reducir los insumos químicos en los sistemas agrícolas. La presente tesis doctoral está enfocada en estudiar el potencial de Trichoderma como bioestimulante en plantas de trigo en condiciones de escasez de agua, así como el efecto de su aplicación en el microbioma de este cultivo. [EN]Agriculture is part of the backbone of our current society, whose constant growth demands an increase in crop yields to ensure the supply of the entire population. However, all predictions point out that climate change will negatively affect crop production and food security worldwide in the coming years. Wheat is one of the most widely consumed crops in the world, being a staple food and in many cases necessary in the diet of a large part of humans and also of animals. However, its production is negatively affected by drought episodes, which are becoming more intense and frequent due to climate change. In this context, the challenge for modern agriculture is to achieve yield increases as well as the resilience and adaptation of crops to variations in environmental conditions. However, current agronomic practices are highly dependent on the use of agrochemicals, whose inadequate and sometimes indiscriminate application is causing soil contamination and biodiversity losses. In recent years, the use of microorganisms as biostimulants and biofertilizers has emerged as a promising alternative to replace or reduce chemical inputs in agricultural systems. The present doctoral thesis is focused on evaluating the potential of Trichoderma as a biostimulant agent in wheat plants under water scarcity conditions, as well as the effect of its application on the microbiome of this crop