Characterization of mineral phosphate solubilizing and plant growth promoting bacteria from termite soil of arid region

Abstract

Five highly efficient phosphate solubilizing bacteria, viz., Pantoea sp. A3, Pantoea sp. A34, Kosakonia sp. A37, Kosakonia sp. B7 and Bacillus sp. AH9 were isolated from termitorial soils of Sanjivani island of southern Maharashtra, India. These isolates were characterized and explored for phosphate solubilization and plant growth promotion. Among these, Bacillus sp. AH9 showed highest phosphate solubilization index (3.5) and solubilization efficiency (250%) on Pikovskaya agar. Interestingly, Pantoea sp. A34 displayed maximum mineral phosphate solubilization (1072.35 mg/L) in liquid medium and during this period the pH dropped to 3.13. All five isolates had highest P solubilization at 48 h after inoculation. During mineral phosphate solubilization, both gluconic acid and 2-keto gluconic acid were produced by Kosakonia and Bacillus isolates, while only 2-keto gluconic acid was detected in Pantoea isolates. Highest organic acid (39.07 ± 0.04 g/L) production was envisaged in Bacillus sp. AH9, while Pantoea sp. A34 produced the least amount (13.00 ± 0.01 g/L) of organic acid. Seed bacterization with Pantoea sp. A3 and Kosakonia sp. A37 resulted in ~ 37% and ~ 53% increase in root length of tomato seedlings, respectively, while Pantoea sp. A34 and Kosakonia sp. B7 had deleterious effects on root length as well as overall growth of the seedlings. To our knowledge, this is the first report of plant growth promoting potential of microorganisms isolated from termitorial soil of Sanjivani island, which is a drought-prone area. Therefore, such efficient growth promoting P solubilizers can offer an effective solution for sustainable agriculture in arid, dryland farming and drought-prone regions.

Use of termitarium soil as a viable source for biofertilizer and biocontrol

“…The bacterial isolates recovered in this study revealed higher affinity to solubilize phosphorus (117 bacterial isolates) than potassium. Chakdar et al (2018) stated that termite mound soils hold higher amount of phosphorus when compared to the surrounding soils due to the presence of highly efficient phosphate-solubilizing bacteria. Ability of these phosphate solubilizing bacteria to solubilize inorganic and organic phosphorus is seen as significant features for increasing soil fertility and their use as inoculants concurrently can increase plant phosphorus uptake and increase crop yield (Hameedaa et al 2008).…”

Development and Application of Low-Cost and Eco-Sustainable Bio-Stimulant Containing a New Plant Growth-Promoting Strain Kosakonia pseudosacchari TL13

“…Within genus Kosakonia this ability was previously reported only in the strain Kosakonia sp. A37 ( Chakdar et al, 2018 ).…”

Unveiling Plant-Beneficial Function as Seen in Bacteria Genes from Termite Mound Soil

“…In principle, the transformation of glucose to gluconic acid through the intermediate formation of glucono-1,5-lactone occurs in the periplasmic space (Yamada et al 2003) and this process depends on the activity of a pyrroloquinoline quinone (PQQ)-linked membrane-bound glucose dehydrogenase, and the pqqABCDEF operons are essential for PQQ biosynthesis (Andreeva et al 2011). Chakdar et al (2018) reported that Kosakonia and Bacillus isolated from termite mound soils produced both 2-keto gluconic acid and gluconic acid during Indole acetic acid (IAA) is another significant hormone that is needed by plants to ensure proper growth (Guo et al 2018). Termite mound and adjacent soil metagenomes contained ipdC and ppdC that code for Indole-3-pyruvate decarboxylase and phenylpyruvate decarboxylase respectively, enzymes that produce IAA from tryptophan (Sugawara et al 2015).…”