Biological Control Mechanisms of Fluorescent Pseudomonas Species involved in Control of Root Diseases of Vegetables/ Fruits

Abstract

Root diseases of vegetables and fruits are known to be highly destructive which can cause a significant economic yield loss in those crops. The application of fungicides to control root diseases has been increasingly curtailed by the development of pathogen resistance to many key fungicides, expensive, inconsistence, and negative public perception regarding the safety of pesticides and consequent restrictions on fungicide use. Moreover, chlamydospores and mycelium of certain fungi can survive in the soil for several years. Biological control methods that reduce the population of pathogen in the soil appear to be the most practical method. Therefore, plant disease control has generally been focused on the use of biological control agents. Fluorescent pseudomonads have frequently been considered as effective biological control agents against soil-borne plant pathogens because of their rapid and aggressive colonization of plant roots. It has been shown that the fluorescent pseudomonads exert several mechanisms in suppression of plant root diseases, and that such mechanisms differed among the strains. The aim of this study is to analyze biocontrol mechanisms of fluorescent pseudomonads for the traits or metabolites involved in biocontrol of plant root diseases.

Evaluation ofPseudomonas chlororaphissubsp.aurantiacaSR1 for growth promotion of soybean and for control ofMacrophomina phaseolina

“…Thus, BCAs partake at increasing the currently available practices for the management of plant diseases. The mechanisms on which BCAs are based are well defined and include production of antifungal compounds, induction of systemic resistance and spatial and nutrient competition (Anjaiah, 2004). The fluorescent Pseudomonas have emerged as the largest and potentially most promising group of plant growth-promoting rhizobacteria involved in the biological control of plant diseases (Kloepper, Leong, Teintze, & Schroth, 1980;Mercado-Blanco & Bakker, 2007;Suslow & Schroth, 1982).…”

“…Soybean plants are sensitive to several phytopathogenic fungal genera such as Macrophomina, which causes charcoal rot, dry root rot and damping-off in several agronomically important crops. Macrophomina predominates in the tropical and sub-tropical areas and causes diseases in a broad group of hosts (Anjaiah, 2004). Substantial yield decreases of soybean are declared annually due to M. phaseolina (Tassi) Goid.…”

Effects of Intercropping on Rhizosphere Soil Bacterial Communities in Amorphophallus konjac

“…In our reasearch, the genus Pseudomonas was significantly affected by the different cultivation modes. Pseudomonas contains has many beneficial bacterial species that can be used to control root diseases of vegetables and fruits [29] and the tuber-rotting disease of Jerusalem artichoke [30]. The disease incidence under monocrop and intercropping conditions was 73.1% and 3.1% in the third year of continuous cropping, respectively (Figure 2).…”

Potential of Pseudomonas putida PCI2 for the Protection of Tomato Plants Against Fungal Pathogens

“…After complete emergence at 1 week, seedlings were thinned out to one per pot. The four treatments were as follows: (1) non-bacterized, non-infested healthy control plants, (2) plants non-bacterized, infested with F. oxysporum MR193 1-3 weeks after seeding, (3) plants bacterized with PCI2 and infested with F. oxysporum MR193 1-3 weeks after seeding, and (4) plants bacterized with PCI2. Each tomato seedling was infested with a 5 ml suspension of F. oxysporum MR193, using the adjusted inoculum density as mentioned above.…”

“…Many pathogens including fungi, bacteria, viruses, and nematodes are associated with infection of crop plants. Among these, phytopathogenic fungi are one of the major factors limiting crop production [2]. Tomato is susceptible to, among other fungi, subspecific taxa of Fusarium oxysporum, which are fungi that grow and survive for long periods on organic matter, in the soil and in the rhizosphere.…”