Endophytic Bacteria Improve Root Traits, Biomass and Yield of Helianthus tuberosus L. under Normal and Deficit Water Conditi

Abstract

Drought is more concerned to be a huge problem for agriculture as it affects plant growth and yield. Endophytic bacteria act as plant growth promoting bacteria that have roles for improving plant growth under stress conditions. The properties of four strains of endophytic bacteria were determined under water deficit medium with 20% polyethylene glycol. Bacillus aquimaris strain 3.13 showed high 1-aminocyclopropane-1-carboxylate (ACC) deaminase production; Micrococcus luteus strain 4.43 produced indole acetic acid (IAA). Exopolysaccharide production was high in Bacillus methylotrophicus strain 5.18 while Bacillus sp. strain 5.2 did not show major properties for drought response. Inoculation of endophytic bacteria into plants, strain 3.13 and 4.43 increased height, shoot and root weight, root length, root diameter, root volume, root area and root surface of Jerusalem artichoke grown under water limitation, clearly shown in water supply at 1/3 of available water. These increases were caused by bacteria ACC deaminase and IAA production; moreover, strain 4.43 boosted leaf area and chlorophyll levels, leading to increased photosynthesis under drought at 60 days of planting. The harvest index was high in the treatment with strain 4.43 and 3.13 under 1/3 of available water, promoting tuber numbers and tuber weight. Inulin content was unchanged in the control between well-watered and drought conditions. In comparison, inulin levels were higher in the endophytic bacteria treatment under both conditions, although yields dipped under drought. Thus, the endophytic bacteria promoted in plant growth and yield under drought; they had outstanding function in the enhancement of inulin content under wellwatered condition.

Influence of Microbial Priming on Germination and Seedling Growth Traits of Compact Cotton CO17

“…The inoculation of PPFM TNAU1 and Azospirillum sp7 strain resulted in an increment of 57.3 and 45.6% respectively, over the control. Our results are in corroboration with Wang et al [38] and Namwongsa et al [39].…”

PGPR Mediated Alterations in Root Traits: Way Toward Sustainable Crop Production

“…SB1.ACC2 reduced ethylene production and promoted the plant growth by inducing salinity tolerance in rice (Bal et al, 2012). Inoculation of Jerusalem artichoke (Helianthus tuberosus L.) with IAA and ACC deaminase producing Bacillus aquimaris strain 3.13 and Micrococcus luteus strain 4.43 drought conditions increased shoot height and weight, length, diameter, volume, area of root ultimately improving harvest index (Namwongsa et al, 2019). Similarly, Rice (Oryza sativa) seedlings inoculated with IAA and ACC deaminase producing Pseudomonas fluorescens strain REN, exhibited enhanced root length under flooding (Etesami and Alikhani, 2016).…”

The Role of Plant-Associated Bacteria, Fungi, and Viruses in Drought Stress Mitigation

“…Phytohormones, such as indole acetic acid (IAA), gibberellins, ethylene, abscisic acid (ABA), and cytokinin, in addition to playing a crucial role in plant growth and development, can help plants cope with abiotic stresses ( Cassán et al, 2014 ; Porcel et al, 2014 ). PGPR have been reported to promote plant growth under drought conditions by manipulating plant hormones, such as cytokinins ( Liu et al, 2013 ), ABA ( Egamberdieva et al, 2017 ), and IAA ( Jochum et al, 2019 ; Namwongsa et al, 2019 ), and decreasing ethylene production ( Belimov et al, 2015 ).…”