Distribution and Biodiversity of Seed-Borne Pathogenic and Toxigenic Fungi of Maize in Egypt and Their Correlations with Weather Variables

The seed microbiomes of staple food crops

The scientific community increasingly recognized that seed microbiomes are important for plant growth and nutrition. The versatile roles and modulating properties that microbiomes hold in the context of seeds seem to be an inherited approach to avert adverse conditions. These discoveries attracted extensive interest, especially in staple food crops (SFCs) where grain was consumed as food. Along with the rapid expansion of population and industrialization that posed a severe challenge to the yield of SFCs, microbiologists and botanists began to explore and engineer seed microbiomes, for safer and more fruitful grain production. To utilize seed microbiomes, we present an overall review of the most updated scientific literature on three representative SFCs (wheat, rice and maize) using the 5W1H (Which, Where, What, Why, When and How) method that provides a comprehensive understanding of the issue. These include which factors determine the composition of seed microbiomes? Where do seed microbiomes come from? What are these seed microbes? Why do these microbes choose seeds as their destination and when do microbes settle down and become seed communists? In addition, how do seed microbiomes work and can be manipulated effectively? Therefore, answering the aforementioned questions regarding SFCs seed microbiomes remain fundamental in bridging endophytic research gaps and harnessing their ecological services.

Management of Fusarium Wilt Disease of Maize (Zea mays L.) with Selected Antimycotic Plant Extracts and Inhibitory Bacillus Strains

Maize (Zea mays L. var. Everta) is an economically significant crop cultivated worldwide. Unfortunately, microbial diseases, especially, mycopathogens such as Fusarium species, militate against the production of maize. Protective microbial species and bioactive plant extracts have been studied in the control of plant pathogens. However, there is a dearth of information on their comparative efficacy and effect on wilt disease of maize caused by Fusarium solani, as investigated in this study. Using the ITS and 16s rDNA primers for fungal pathogen and bacterial strains, respectively, the mycopathogen was confirmed as Fusarium solani FCI20, while biocontrol Bacillus strains were identified as Bacillus velezensis EBs02 and Bacillus thuringiensis EBs04. Fusarium solani FCI20 successfully infected maize seedlings through rhizosphere inoculation, and caused severe leaf chlorosis, necrosis and wilt in maize seedlings. Bacillus thuringiensis EBs04 expressed the highest in vitro mycelial inhibition (85.20%), followed by Gmelina arborea (78.58%), while Milicia excelsa appeared to express the lowest mycelial inhibition potential (49.95%). Bacillus velezensis EBs02 expressed the highest in vivo disease severity reduction in maize seedlings (with percentage disease control of 84.16), while B. thuringiensis-treated plants had the lowest incidence of wilt disease (4.32%). However, contrary to their in vitro mycelial inhibition potential, B. velezensis EBs02, Gmelina arborea, Milicia excelsa and Cola nitida expressed radically different levels of in vivo wilt disease control in maize seedlings. Consequent upon the biocontrol patterns observed in this study, in vivo assay should be considered in the preliminary selection of promising biocontrol agents against phytopathogens, such as Fusarium species.