Abstract
In this study, the biocontrol ability and colonization behavior of a highly antagonistic Streptomyces mutabilis strain, named IA1, recently isolated from a Saharan soil, were assessed on wheat seedlings. In this study we showed that strain IA1 secretes IAA and GA3 and is able to enhance growth of wheat seedlings. Using DOPE-FISH coupled with confocal laser scanning microscopy (CLSM), we observed moreover that following caryopsis inoculation and plant growth the strain can colonize the rhizoplane, the surface of caryopsis as well as the endorhiza, crossing from the rhizodermis up to the vascular system. Interestingly, further visualizations revealed that the actinobacterial strain could also be endophytic inside the caryopsis up to the endocarp layer (the dried fruit part, not the seed part of grain). Disease caused by Fusariumculmorum was further evaluated on seedlings and results showed that coated seeds with strain IA1 can reduce both disease occurrence (64.7%) and decrease severity (79.6%). This study showed that strain IA1 derived from a Saharan soil could protect a temperate crop from F. culmorum seedling blight, promote growth and colonize various niches on the surfaces of the phytosphere (roots, seeds) as well as plant endosphere compartments.
Highlights
Various beneficial bacteria support their host plants by increasing growth and/or by protecting them against pathogenic diseases (Bakker et al, 2007; Lugtenberg and Kamilova, 2009)
To further determine mechanisms involved in plant growth promotion, indole-3-acetic acid (IAA) and gibberellic acid (GA3) productions by strain IA1 were evaluated
Data showed that strain IA1 produced both IAA and GA3 under controlled conditions of fermentation with amounts rating of 74.39 ± 1.46 and 94.24 ± 23.66 μg ml−1, respectively (Table 2)
Summary
Various beneficial bacteria support their host plants by increasing growth and/or by protecting them against pathogenic diseases (Bakker et al, 2007; Lugtenberg and Kamilova, 2009). Other sources can be the caulosphere, phyllosphere, anthosphere as well as the carposphere as parts of the phytosphere environment, demonstrating the various sources of beneficial microbes (Compant et al, 2011) Among these bacteria, a subset can enter inside plants and establish an intimate interaction with their hosts. Microorganisms derived from extreme environments such as desert soils may represent a promising resource for new types of microorganisms (Barrow et al, 2008; Compant et al, 2010b; Yekkour et al, 2012) Due to their enhanced resistance against environmental stresses, the application of these microorganisms as biofertilizers and/ or biopesticides in crop production, even under temperate conditions, could confer various advantages as compared to microorganisms applied so far, under changing climate conditions (Barrow et al, 2008; Compant et al, 2010b)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
