Assessment of plant growth-promoting stress-tolerant endophytes screened from Bougainvillea glabra for the growth of Triticum aestivum L. and Zea mays

Abstract

Globally, more than 5.2 billion hectares of farming fields are damaged through erosion, salinity, and soil deterioration. Salt stress-tolerant bacteria have plant growth-promoting (PGP) characteristics that can be used to overcome environmental stresses. Isolation and screening of salt-tolerant endophytes from Bougainvillea glabra were achieved through surface sterilization of leaves, followed by their cultivation on 0.5% NaCl-supplemented media. The performance of isolates for indole acetic acid (IAA) production, phosphate solubilization, ACC deaminase activity, ammonia production, siderophore production, and stress tolerance was determined. In the present study, 5 morphologically distinct salt-tolerant endophytic bacteria were cultured. Out of 5 isolates, 60% salt-tolerant endophytes showed phosphate solubilization, 100% IAA production, 40% ACC-deaminase activity, 100% siderophore production, 40% ammonia production and 60% HCN production. Dendrogram generated based on stress tolerance showed three clusters: clusters 1 and 2 containing two isolates and cluster 3 containing 1 isolate. Based on the highest PGP activities, BoGl17 and BoGl21 isolates were chosen and further tested for wheat and corn growth promotion. The isolates increased wheat shoot and root dry weight by 40% and 80%, and by 69% and 126% for BoGl17 and BoGl21, respectively. The bacterial isolates identified as Pseudomonas reidholzensis BoGl17 had 95.59% identity with Pseudomonas reidholzensis strain ID3, while the isolate Bacillus aerius BoGl21 had 90.96% identity with Bacillus aerius strain 24K based on phenotypic features and 16S rRNA gene sequencing results. Both isolates significantly improved plant growth as compared to uninoculated plants.

Journal of Plant Protection Research

“…A previous study (Akter and Oue 2018) showed that microbial inoculants improved root growth which encouraged plant growth and nutrient access to plant roots, i.e., nitrogen (N), phosphorus (P), and potassium (K). In an earlier study, Karnwal (2020) reported the beneficial effects of salt-tolerant PGP bacterial isolates BoGl17 on the growth of Triticum aestivum L. var. HD 2687 and Zea mays var.…”

“…The Food and Agriculture Organization (FAO) and United Nations Environment Programme (UNEP) statistics have reported that 5.2 billion hectares of agricultural land are currently ruined through erosion, salinity and deterioration of soil (Numan et al 2018). Out of this, 0.4 billion hectares of land is ruined globally due to salinity (20% of agricultural and 50% of croplands) and threaten agricultural productivity (Karnwal 2020). To overcome the negative impact of the salt environment, researchers are developing various strategies to produce salt stress-resistant plant varieties.…”

Effect of halotolerant plant growth-promoting rhizobacteria from Bougainvillea glabra on wheat and maize seedlings under NaCl stress

“…Bacterial isolates intended for the current research were isolated and identified from B. glabra rhizosphere grown at the Bhojia Institute of Life Sciences, Budh, Baddi, Himachal Pradesh, India (located at latitude 30.952802 and longitude 76.776914) as explained in an earlier investigation of Karnwal (2017). The rhizospheric soil samples were serially diluted up to 10 !6 , and 0.1 ml of suspension from the 10 !6 dilution was spread onto a modified nutrient agar medium (NAM) enriched with 4% salt (NaCl) as described by Karnwal (2020). The plates were incubated for up to 72 h at 28 ± 1EC in dark.…”

“…The surface-sterilized seeds were immersed in a bacterial suspension and rotated at 150 rpm for 2 h at 28EC. The seeds were then air-dried in a laminar airflow hood for 60 min (Karnwal, 2020). Ten seeds per crop were placed on a sterile moistened Whatman No.…”

“…It is a highly drought-tolerant, salttolerant, and wind-resistant plant that grows in the welldrained acidic soil with a pH between 5.5 and 6.0 (Islam et al, 2016;Abarca-Vargas and Petricevich, 2018). Earlier, the effect of endophytic bacteria isolated from Bougainvillea glabra was examined (Karnwal 2020), and the beneficial effect of endophytes on Triticum aestivum L. and Zea mays seedlings under saline condition was reported. However, little attention has been given to the rhizospheric microorganisms in B. glabra and their Effect of halotolerant plant growth-promoting rhizobacteria from Bougainvillea glabra on wheat and maize seedlings 351 plant growth promoting and salinity tolerance traits.…”