Prospecting Endophytic Bacteria Endowed With Plant Growth Promoting Potential Isolated From Camellia sinensis

Abstract

Endophytes are well-acknowledged inoculants to promote plant growth, and extensive research has been done in different plants. However, there is a lacuna about the endophytes associated with tea clones and their benefit to promote plant growth. The present study focuses on isolating and characterizing the beneficial endophytic bacteria (EnB) prevalent in commercially important tea clones cultivated in North Eastern India as plant growth promoters. Diversity of culturable EnB microbiome, in vitro traits for plant growth promotion (PGP), and applicability of potent isolates as bioinoculant for in vivo PGP abilities have been assessed in the present study. A total of 106 EnB identified as members of phyla Proteobacteria, Firmicutes, and Actinobacteria were related to 22 different genera and six major clusters. Regarding PGP traits, the percentage of isolates positive for the production of indole acetic acid, phosphate solubilization, nitrogen fixation siderophore, ammonia, and 1-aminocyclopropane-1-carboxylic acid deaminase production were 86.8, 28.3, 78.3, 30.2, 95.3, and 87.7, respectively. In total, 34.0, 52.8, and 17.0% of EnB showed notable production of hydrolytic enzymes like cellulase, protease, and amylase, respectively. Additionally, based on the bonitur score, the top two isolates K96 identified as Stenotrophomonas sp. and M45 identified as Pseudomonas sp. were evaluated for biofilm formation, motility, and in vivo plant growth promoting activity. Results suggested strong biofilm formation and motility in K96 and M45 which may attribute to the colonization of the strains in the plants. Further in vivo plant growth promotion experiment suggested sturdy efficacy of the K96 and M45 as plant growth promoters in nursery condition in commercial tea clones Tocklai vegetative (TV) TV22 and TV26. Thus, this study emphasizes the opportunity of commercialization of the selected isolates for sustainable development of tea and other crops.

Production and Characterization of Indole Acetic Acid of Endophytic Bacteria isolated from Kalanchoe pinnata (Lam.) in Optimized Media

“…were ground in 2% saline and serially diluted and plated on LB agar for endophytic isolation. After 24 hrs, morphologically diverse bacterial colonies were selected and maintained at 4 • C till further use (11) .The morphological characters and biochemical tests were followed from standard laboratory manual (4) . For authentic conformation, the molecular identification was carried out by 16S rRNA sequencing for isolated endophytes (11,12) .…”

“…An optimum pH and temperature favours the maximum production of phytohormones for endophytic bacteria of different species. It was reported that pH 7 and 8 induces the maximum production of IAA (11,13,14) for various endophytes. In this study, B. thrungiensis produced 5.97±0.0653 µg/ml and 6.27±0.0653 µg/ml, B. paranthracis gave 24.33±0.653 µg/ml and 32.57±0.523 µg/ml, S. xylosus produced 42.3±0.0653 µg/ml and 44.17±0.065 µg/ml, B. cereus produced 21.67±0.864 µg/ml and 23.73±0.173 µg/ml at 30 and 120 minutes at pH 8 than pH 6, 7 and 9 shown in Table 2.…”

Dynamics, phylogeny and phyto-stimulating potential of chitinase synthesizing bacterial root endosymbiosiome of North Western Himalayan Brassica rapa L.

“…To uphold a stable relationship with the host, these endophytic bacterial strains have ceaselessly evolved with the plants across the family lines to ameliorate it and endure biotic and abiotic stress through multiple direct and indirect mechanisms 6 . Most of them have a significant bearing on the growth and metabolism of the plants and 8 are metabolically versatile, bearing the population load relatively short to their pathogenic counterparts 9 . There has been a close association of microbes with the plants for a variety of reasons, such as growth elevation, improved yield, and disease control; such associations continue to happen for centuries and are driven by the dependence of the microbes for their survival on the host plants 10 .…”

Deciphering the potential of a plant growth promoting endophyte Rhizobium sp. WYJ-E13, and functional annotation of the genes involved in the metabolic pathway

“…Besides, beneficial endophytes have also been found in many genera, including Stenotrophomonas sp. ( Hazarika et al, 2021 ), Pantoea cypripedii and Kosakonia arachidis ( Singh, R. K., et al, 2021 ), Pennisetum giganteum ( Yankey et al, 2022 ), and Klebsiella aerogenes ( Cheng et al, 2022 ).…”