Biodiversity of the phosphate solubilizing microorganisms (PSMs) population from the rice rhizosphere soils of the two agro-ecological zones of Cameroon

Abstract

The plant rhizosphere microorganisms having the phosphate solubilizing capacity can convert the insoluble soil organic and inorganic phosphates into a soluble form and make the phosphorus (P) available to the plant. With the objective of evaluating the phosphate solubilizing microorganism populations under the rice rhizosphere, soils samples were collected in three locations of two agro-ecological zones of Cameroon and analyzed for their PSMs diversity. Isolation of microorganisms was made on non selective nutrient agar plates and the phosphate solubilizing activity of isolates was tested on National Botanical Research Institute's Phosphate growth medium (NBRIP) amended with sparingly soluble rock phosphates of different origins. The morphological description of isolates allowed evaluating the phosphate solubilizing microorganism's diversity under the rice rhizospheric soil. The most probable number of PSMs ranged between 22 and 53% with an average of 48%, 52.80% and 22.44% for Nkolbisson, Nyokon and Santchou respectively. The 65 isolates obtained from all locations were distributed in four diverse groups. The index of solubilization ranged between 2.70 and 7.24 depending on isolate. From a total of 65 isolates obtained from the three sampling sites, 46 were phosphate solubilizing isolates among which: 20 were of low solubilization, 16 of medium and 10 of high solubilization. This is the first work reporting phosphate solubilizing microorganisms on rice rhizosphere in Cameroon. However, the selection of phosphate solubilizing microorganisms as possible inoculation tools for phosphate-deficient soils should focus on the integral interpretation of laboratory assays, greenhouse experiments as well as field trials.

Identification of plant growth promoting antagonistic bacteria against blast disease of rice

“…Plant rootsassociated PSB have been considered as one of the possible alternatives for inorganic phosphate fertilizers for promoting plant growth and yield (Thakuria et al, 2004). Plant growth and phosphate uptake have increased in many crop species due to the results of PSB inoculants (Fankem et al, 2015;Gusain et al, 2015). It has also been documented that the application rates of phosphate fertilizers reduced to 50% by inoculating phosphate solubilizing microbes (PSM) in crops without significantly reducing crop yield (Yazdani et al, 2009).…”

Effets de la déficience en phosphore du sol sur la croissance et le développement du sésame (<i>Sesamum indicum</i> L.)

“…Une carence en P en début de saison entraîne une restriction irréversible précoce du développement des cultures et qui peut réduire considérablement les populations de plantes (Sinclair et Vadez, 2002), le nombre de feuilles (Lynch et al, 1991) et le développement racinaire, qui à son tour affecte la capacité des plantes à absorber l'eau des horizons les plus profonds du sol sous de faibles précipitations (Marschner, 1995). Le phosphore est donc un nutriment minéral essentiel nécessaire à la croissance des plantes, car il s'agit d'un composant de molécules importantes (Badjissaga, 2007 ;Shoko et al, 2010 ;Fankem et al, 2015). Sa carence décroit les rendements par réduction de la surface foliaire chez le maïs et par la réduction du nombre de rameaux chez les graminées (Badjissaga, 2007).…”

Bioprospecção de bactérias solubilizadoras de fosfato em solos com diferentes fertilidades

“…Regarding the onset of solubilization (Table 1), 72 and 16% of the 32 isolates studied here showed an early onset of solubilization for calcium and iron phosphates, respectively. The time of onset of solubilization is related to the ability of a microorganism to adapt to the environment in which it was inserted (Fankem et al, 2016). Therefore, this characteristic highlights the potential of using an isolate in agricultural cultivation environments.…”