Abstract
The aim of this work was to select and characterize native Cuban fluorescent Pseudomonas from the rhizosphere of Oryza sativa with in vitro and in vivo antagonistic activity against Pyricularia oryzae. A total of 200 isolates were recovered with the typical growth and cultural characteristics of fluorescent Pseudomonas. The results showed that 12.5% of total isolates were capable of inhibiting mycelial growth, with different levels of inhibition between strains. Six of them (AI03, AI05, AI08, AJ01, AJ13 and AJ29) were able to reduce disease severity and incidence in vivo whereas only four (AI05, AJ13, AJ01 and AI08) showed efficient control of P. oryzae in greenhouse conditions. Pseudomonas fluorescens AI05 and Pseudomonas putida AJ13 were able to inhibit in vitro the mycelial growth of P. oryzae and to reduce symptom severity of Pyricularia infection. The production of lytic enzymes, siderophores, hydrogen cyanide (HCN), as well as the detection of genes encoding antibiotics and bacterial motility were also assessed for both strains. They were able to fix nitrogen, produce indolic compounds and to solubilize Pi. These results demonstrate the potential use of P. fluorescens AI05 and P. putida AJ13 as a biocontrol agent for the protection of rice plants from P. oryzae infection. Key words: Biocontrol, rice blast, Pyricularia, Pseudomonas, plant growth-promoting bacteria.
Highlights
Rice (Oryza sativa L.) is an important crop for human consumption
From the 200 isolates that showed the typical characteristics of fluorescent Pseudomonas, 25 were capable of inhibiting mycelial growth of at least one of the five fungal strains (Figure 1)
Of the 200 isolates of fluorescent Pseudomonas evaluated, 25 of them showed in vitro antagonistic activity against P. oryzae
Summary
Rice (Oryza sativa L.) is an important crop for human consumption. This cereal is the staple food for over half the world population and is considered the world’s largest by the size of the area where it is grown and the number of people who depend on their crop (IRRI, 2002). Controlling diseases that may attack the crop is of great importance to increase productivity in rice growing areas. Rice blast, caused by Pyricularia oryzae (teleomorph = Magnaporthe oryzae) is one of the most important diseases, due to its worldwide distribution, destructiveness and high degree of pathogenicity (Thuan et al, 2006; Rodríguez et al, 2007). Rice blast can cause up to 100% in yield reduction, depending on the cultivar susceptibility, cropping technology and climatic conditions (Prabhu et al, 2009, Magar et al, 2015). Infections are mostly reported to occur in leaves and stems, seeds and roots may be infected by P. oryzae, using the typical developmental processes of root-infecting fungi (Sesma and Osbourn, 2004)
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
