Sporisorium scitamineum is the causal agent of sugarcane smut disease. The fungus establishes a biotrophic interaction with sugarcane tissues, and unlike smut fungi of other monocot hosts, the primary meristem of sugarcane plants develops a whip-like structure instead of a tumour-like galls emerging from floral structures (tassels and ears). We examined (GFP)-tagged S. scitamineum infecting tissues of three sugarcane genotypes with distinct responses to smut (susceptible, intermediate resistant and resistant). Mating compatible haploid cells gfp-expressing were obtained by Agrobacterium tumefaciens-mediated transformation (ATMT) using the integrative vector pFAT-gfp. Regardless of the inoculation method (drop inoculation and hypodermal syringe inoculation), all genotypes were colonised by the fungus. GFP-tagged strains of opposite mating reaction were able to: (a) grow in vitro as fluorescent yeast-like cells; (b) generate infectious dikaryon; (c) penetrate sugarcane tissues; (d) colonise tissues by growing a filamentous network; and (e) form the characteristic highly branched hyphae within host cells. Fungal colonisation 160 DAI revealed an association of the fungus with vascular vessels disrupting their organisation in all three genotypes analysed. However, the resistant plants did not develop whips spanning the experiment time. The first whips emerged 76 DAI from plants of the susceptible genotype whereas for intermediate resistant plants whips were detected at 137 DAI. These whips were dissected and fluorescent sporogenesis and teliospore maturation were analysed. In vitro germination of recovered teliospores revealed after meiosis the formation of a three-celled hyphal filament, where the fourth cell was likely maintained in the teliospore coat. These cells showed independent segregation of the gfp marker, as a result of gfp insertions in different chromosomes of each compatible haploid strain. This work presents the complete fungal life cycle of GFP-marked S. scitamineum to study developmental stages in planta.

The beneficial features of Bacillus thuringiensis (Bt) are not limited to its role as an insecticide; it is also able to promote plant growth interacting with plants and other plant growth-promoting rhizobacterium (PGPR). The PGPR Bt strain RZ2MS9 is a multi-trait maize growth promoter. We obtained a stable mutant of RZ2MS9 labelled with green fluorescent protein (RZ2MS9-GFP). We demonstrated that the Bt RZ2MS9-GFP successfully colonizes maize's roots and leaves endophytically. We evaluated whether RZ2MS9 has an additive effect on plant growth promotion when co-inoculated with Azospirillum brasilense Ab-V5. The two strains combined enhanced maize's roots and shoots dry weight around 50% and 80%, respectively, when compared to the noninoculated control. However, non-differences were observed comparing RZ2MS9 alone and when co-inoculated with Ab-V5, In addition, we used co-inoculation experiments in glass chambers to analyse the plant's volatile organic compounds (VOCs) production during the maize-RZ2MS9 and maize-RZ2MS9-Ab-V5 interaction. We found that the single and co-inoculation altered maize's VOCs emission profile, with an increase in the production of indoles in the co-inoculation. Collectively, these results increase our knowledge about the interaction between the Bt and maize, and provide a new possibility of combined application with the commercial inoculant A. brasilense Ab-V5.

Mangroves are ecosystems located in the transition zone between land and sea that serve as a potential source of biotechnological resources. Brazil's extensive coast contains one of the largest mangrove forests in the world (encompassing an area of 25,000 km2 along all the coast). Endophytic bacteria were isolated from the following three plant species: Rhizophora mangle, Laguncularia racemosa and Avicennia nitida. A large number of these isolates, 115 in total, were evaluated for their ability to fix nitrogen and solubilize phosphorous. Bacteria that tested positive for both of these tests were examined further to determine their level of indole acetic acid production. Two strains with high indole acetic acid production were selected for use as inoculants for reforestation trees, and then the growth of the plants was evaluated under field conditions. The bacterium Pseudomonas fluorescens (strain MCR1.10) had a low phosphorus solubilization index, while this index was higher in the other strain used, Enterobacter sp. (strain MCR1.48). We used the reforestation tree Acacia polyphylla. The results indicate that inoculation with the MCR1.48 endophyte increases Acacia polyphylla shoot dry mass, demonstrating that this strain effectively promotes the plant's growth and fitness, which can be used in the seedling production of this tree. Therefore, we successfully screened the biotechnological potential of endophyte isolates from mangrove, with a focus on plant growth promotion, and selected a strain able to provide limited nutrients and hormones for in plant growth.

Bacillus sp. strain RZ2MS9 is a multitrait soybean and maize growth-promoting bacterium isolated in Brazil from guarana’s rhizosphere. Here, we present the draft genome sequence of RZ2MS9 and its genes involved in many features related to plant growth promotion.

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