Promoting growth and production of sunchoke (Helianthus tuberosus) by co-inoculation with phosphate solubilizing bacteria and arbuscular mycorrhizal fungi under drought

Abstract

Due to different functions of phosphate solubilizing bacteria (PSB) and arbuscular mycorrhizal fungi (AMF), their potential synergistic effects on enhancing plant growth and yield are worth investigating, especially under adverse conditions. This work focused on the isolation of PSB and characterization for their plant growth promoting properties under drought. The most efficient P solubilizing bacterium was isolated and identified as Burkholderia vietnamiensis strain KKUT8-1. Then, a factorial experiment on the performance of sunchoke (Helianthus tuberosus) was set up with four factors, viz., PSB (presence or absence of KKUT8-1), AMF (presence or absence of Rhizophagus aggregatus), rock phosphate (RP; added or not) and moisture (well-watered (WW) or drought (DS) conditions). Sunchoke performance was enhanced by the presence of AMF, whereas addition of PSB had a positive effect on SPAD values and inulin concentration. Drought reduced plant performance, while addition of RP reduced photosynthetic rate. There was little evidence for synergistic effects between PSB and AMF, except for SPAD values and inulin concentration. Plants that were co-inoculated with AMF and PSB had highest SPAD value, shoot diameter, leaf area, leaf number, chlorophyll concentration, plant biomass, tuber production, root growth and total soluble sugar concentration. Co-inoculated plants also had increased plant water status, reduced electrolyte leakage, and reduced malondialdehyde and proline concentration. Strain KKUT8-1 is the first strain of B. vietnamiensis capable of promoting growth and yield of sunchoke. Enhanced production of sunchoke by a combination of AMF and PSB was much better than the application of RP. Our finding offers an opportunity to develop combinations of biological inoculants for increasing the growth and production of sunchoke under drought in the future.

Arbuscular Mycorrhizal Fungi and Higher Plants

“…AMF colonization can further enhance the level of free amino acids in the plant. AM symbiosis in Helianthus tuberosus and Sesamum indicum increased the level of free amino acids (Gholinezhad and Darvishzadeh 2021;Nacoon et al 2022). Zea mays had higher accumulation of γ-aminobutyric acid, free amino acids, arginine, and ornithine when inoculated with Rhizophagus irregularis as compared to the non-AMF plants growing in water stress conditions .…”

Arbuscular mycorrhizal fungi elevate maize plant tolerance to Antimony, enhancing the nutritive value of seeds

“…Previous studies reported increased the levels of low molecular weight antioxidants in rice and enzymatic antioxidants in maize with the addition of Sb [40]. The symbiotic relationship with AMF has been consistently shown to positively affect the production of secondary compounds in plants [41]. As for previous studies [42,43] [6] who describe a clear increase in the phenolic compounds, especially the flavonoids in roots and leaves, in response to Sb toxicity and was explained by their protective effect against oxidative damage.…”

IAA-producing plant growth promoting rhizobacteria from Ceanothus velutinus enhance cutting propagation efficiency and Arabidopsis biomass

“…B. magaterium ( ATCC 14511) was used as the positive control. The phosphate solubilizing index (PSI) was calculated as a ratio of halo diameter over colony diameter ( Nacoon et al., 2022 ). Hydrogen peroxide was used to test for catalase activity in all the isolates ( Pakpour and Horhan, 2021 ).…”