In vitro Inorganic Phosphate Solubilization Tests of Cowpea Root Nodule Bacteria from Ethiopia

Abstract

Background: Phosphorus is one of the limiting plant nutrients in most soil due to its fixation with metal ions both in acidic and alkaline soil. However, some soil bacteria have potential to solubilize the cation-fixed phosphorus and make it available to plants.Methods: Sixty-six cowpea root nodule bacterial species were tested for inorganic phosphate solubilization (PS). PS potential of the isolates from Ca3 (PO4)2, AlPO4 and FePO4 were tested on four different kinds of agar media. Solublization efficiency was determined as Solubilization Index (SI) on agar media and quantity of bioavailable phosphorous on broth media. Result: About 30% of the bacterial isolates, out of which 60% endophytes were Ca3 (PO4)2 solubilizers on Pikovskaya medium but did not grow on media containing AlPO4 and FePO4 as sole P sources. Isolates showed significant variation (p less than 0.05) in Ca3 (PO4)2 solubilization efficiency on the different culture media and ECE-21 (Pseudomonas putida) was versatile in solubilizing Ca3(PO4)2 from the four test media. However, ECE-26A (Bacillus subtilis) showed the highest PS in broth media (140.8 µg ml-1) indicating the moderate correlation (r=0.5578; p less than 0.05) of PS between solid and liquid media. Amounts of P solubilized and pH change of the culture filtrate was inversely correlated (r=-0.731; p less than 0.01). In general, ECE-21 was the most efficient P solubilizer (SI=2.67±0.1; P=87.74±7.4µg ml-1) solublizers and hence can be an ideal candidate as inoculants for the crop production in Ethiopia after field evaluation.

Bioprospecting and Challenges of Plant Microbiome Research for Sustainable Agriculture, a Review on Soybean Endophytic Bacteria

“…For example, Acinetobacter calcoaceticus , Ochrobactrum haematophilum , B. panacihum , Bacillus subtilis , B. australimaris , B. thuringiensis , B. zhangzhouensis , and Lysinibacillus pakistanensis have been isolated from leguminous crops [ 9 , 18 , 30 ]. Kenasa, Nandeshwar, and Assefa [ 141 ] reported the identification of cowpea root endophytic bacteria, Pseudomonas putida , and Bacillus subtilis phosphate producers in their study. Also, a study by Yasmeen and Bano [ 142 ] reported an increase in soybean yield co-inoculated with phosphate-solubilizing bacteria, Rhizobium and Enterobacter .…”

A Rapid and Efficient Plant Regeneration Protocol using Leaves and Stems with Buds of Euphorbia pulcherrima Willd. ex Klotzsch (Euphorbiaceae)

“…If the culture time is too long, the ex-plants and the medium are prone to produce secretions. And the secretions affect the differentiation, proliferation and growth of the cluster buds (Huang et al, 2014;Kenasa et al, 2021). This experiment found that in the process of cultivating shoots with buds, especially during the transfer process, the clustering buds were easy to flow out of white jelly from the wound after being cut.…”