Combined application of H2S and a plant growth promoting strain JIL321 regulates photosynthetic efficacy, soil enzyme activity and growth-promotion in rice under salt stress

Plant growth-promoting rhizobacteria can effectively reduce the severity of different abiotic stresses like water stress, temperature stress, salt stress, etc. on plant growth and development. The study aimed at isolating salt-tolerant rhizobacteria followed by their morphological, biochemical and plant growth promotion traits evaluation. Sixteen root samples of nine different plant species were collected from two locations of Patuakhali, a coastal southern district of Bangladesh. Thirty rhizobacteria were isolated, fifteen from each location, to assess their halotolerance and plant growth promoting potential. The isolated rhizobacteria were subjected to morphological (viz. shape, colour and elevation), biochemical (viz. Gram reaction, catalase test and HCN production) and growth-promoting traits [viz. phosphate solubilizing ability, salt tolerance, indole-3-acetic acid (IAA) production, and N2-fixation] characterization. Twenty-eight isolates were Gram positive, 27 were catalase positive, and nine showed varying degrees of phosphate solubilization on National Botanical Research Institute of Phosphate (NBRIP) medium. Isolate PWB5 showed the highest phosphate solubilizing index (PSI = 3.83±0.098) on the 6th day. To screen salt-tolerant rhizobacteria, the isolates were cultured in NBA media containing different (0%, 2.5%, 5%, 7.5%, 10%, 12%, 15%) NaCl concentrations. Isolate PWB12 and PWB13 grew at 15% NaCl concentration. Eleven isolates exhibited IAA producing ability on Winogradsky medium amended with L-tryptophan among which four (PMB13, PMB14, PMB15 and PWB6) were strong IAA producers. Twenty-seven isolates were potential N2-fixer and among them, 20 were highly efficient, but none of the isolates was HCN producer. The rhizobacteria isolated in the current research work showed some potential plant growth-promoting traits which seem applicable for crop production, especially, under salt stress condition.

Download Full-text

Bioprospecting desert plant Bacillus endophytic strains for their potential to enhance plant stress tolerance

Scientific Reports ◽

10.1038/s41598-019-54685-y ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 8

Author(s):

Ameerah Bokhari ◽

Magbubah Essack ◽

Feras F. Lafi ◽

Cristina Andres-Barrao ◽

Rewaa Jalal ◽

...

Keyword(s):

Salt Stress ◽

Plant Growth ◽

Growth Promotion ◽

Stress Conditions ◽

Desert Plant ◽

Plant Growth Promoting Bacteria ◽

Fresh Weight ◽

Pgp Traits ◽

Plant Growth Promoting ◽

Growth Promoting

AbstractPlant growth-promoting bacteria (PGPB) are known to increase plant tolerance to several abiotic stresses, specifically those from dry and salty environments. In this study, we examined the endophyte bacterial community of five plant species growing in the Thar desert of Pakistan. Among a total of 368 culturable isolates, 58 Bacillus strains were identified from which the 16 most divergent strains were characterized for salt and heat stress resilience as well as antimicrobial and plant growth-promoting (PGP) activities. When the 16 Bacillus strains were tested on the non-host plant Arabidopsis thaliana, B. cereus PK6-15, B. subtilis PK5-26 and B. circulans PK3-109 significantly enhanced plant growth under salt stress conditions, doubling fresh weight levels when compared to uninoculated plants. B. circulans PK3-15 and PK3-109 did not promote plant growth under normal conditions, but increased plant fresh weight by more than 50% when compared to uninoculated plants under salt stress conditions, suggesting that these salt tolerant Bacillus strains exhibit PGP traits only in the presence of salt. Our data indicate that the collection of 58 plant endophytic Bacillus strains represents an important genomic resource to decipher plant growth promotion at the molecular level.

Download Full-text

Rhizobacteria Isolated from Saline Soil Induce Systemic Tolerance in Wheat (Triticum aestivum L.) against Salinity Stress

Agronomy ◽

10.3390/agronomy10070989 ◽

2020 ◽

Vol 10 (7) ◽

pp. 989 ◽

Cited By ~ 2

Author(s):

Noshin Ilyas ◽

Roomina Mazhar ◽

Humaira Yasmin ◽

Wajiha Khan ◽

Sumera Iqbal ◽

...

Keyword(s):

Salt Stress ◽

Plant Growth ◽

Salinity Stress ◽

Plant Biomass ◽

Growth Promotion ◽

Soluble Sugar ◽

Wheat Crop ◽

Plant Growth Promoting Bacteria ◽

Plant Growth Promoting ◽

Growth Promoting

Halo-tolerant plant growth-promoting rhizobacteria (PGPR) have the inherent potential to cope up with salinity. Thus, they can be used as an effective strategy in enhancing the productivity of saline agro-systems. In this study, a total of 50 isolates were screened from the rhizospheric soil of plants growing in the salt range of Pakistan. Out of these, four isolates were selected based on their salinity tolerance and plant growth promotion characters. These isolates (SR1. SR2, SR3, and SR4) were identified as Bacillus sp. (KF719179), Azospirillum brasilense (KJ194586), Azospirillum lipoferum (KJ434039), and Pseudomonas stutzeri (KJ685889) by 16S rDNA gene sequence analysis. In vitro, these strains, in alone and in a consortium, showed better production of compatible solute and phytohormones, including indole acetic acid (IAA), gibberellic acid (GA), cytokinin (CK), and abscisic acid (ABA), in culture conditions under salt stress. When tested for inoculation, the consortium of all four strains showed the best results in terms of improved plant biomass and relative water content. Consortium-inoculated wheat plants showed tolerance by reduced electrolyte leakage and increased production of chlorophyll a, b, and total chlorophyll, and osmolytes, including soluble sugar, proline, amino acids, and antioxidant enzymes (superoxide dismutase, catalase, peroxidase), upon exposure to salinity stress (150 mM NaCl). In conclusion, plant growth-promoting bacteria, isolated from salt-affected regions, have strong potential to mitigate the deleterious effects of salt stress in wheat crop, when inoculated. Therefore, this consortium can be used as potent inoculants for wheat crop under prevailing stress conditions.

Download Full-text

Halotolerant-Koccuria rhizophila (14asp)-Induced Amendment of Salt Stress in Pea Plants by Limiting Na+ Uptake and Elevating Production of Antioxidants

Agronomy ◽

10.3390/agronomy11101907 ◽

2021 ◽

Vol 11 (10) ◽

pp. 1907

Author(s):

Amir Abdullah Khan ◽

Tongtong Wang ◽

Tayyaba Hussain ◽

Amna ◽

Fayaz Ali ◽

...

Keyword(s):

Antioxidant Enzymes ◽

Salt Stress ◽

Plant Growth ◽

Growth Promotion ◽

Antioxidant Systems ◽

Plant Growth Promoting Bacteria ◽

Mineral Contents ◽

Root And Shoot Length ◽

Plant Growth Promoting ◽

Growth Promoting

Endophytic bacteria are useful for their safe services in plant growth improvement and for ameliorating abiotic and biotic stresses. Salt-tolerant plant-growth-promoting Kocuria rhizophila 14asp (accession number KF 875448) was investigated for its role in pea plants under a saline environment. Salt stress (75 mM and 150 mM NaCl) was subjected to two pea varieties, peas2009 and 9800-10, in a greenhouse under a complete randomized design. Different parameters such as plant growth promotion, relative water content, chlorophyll, antioxidants, and mineral contents were analyzed to elucidate the extent of tolerance persuaded by PGPB (plant-growth-promoting bacteria). Exhibition of adverse effects was noticed in uninoculated varieties. However, inoculation of K. rhizophila improved the morphological parameters, antioxidant enzymes, and minimized the uptake of Na+ in plants under various saline regimes. Pea variety 9800-10 exhibited more tolerance than peas2009 in all traits, such as root and shoot length, fresh and dry biomass, chlorophyll contents, and antioxidant enzymes. Our results showed that halotolerant K. rhizophila inoculation plays a vital role in enhancing plant growth by interacting ingeniously with plants through antioxidant systems, enduring saline conditions.

Download Full-text

Tomato Growth Promotion Induced by Stress Tolerant Phosphate Solubilizing Pseudomonas simiae in Arid trans-Himalaya

Defence Life Science Journal ◽

10.14429/dlsj.3.12565 ◽

2018 ◽

Vol 3 (2) ◽

pp. 105

Author(s):

Diskit Dolkar ◽

Phuntsog Dolkar ◽

Tsering Stobdan ◽

Anand K Katiyar

Keyword(s):

Salt Stress ◽

Plant Growth ◽

Growth Promotion ◽

Tomato Seedling ◽

Seed Bacterization ◽

Insoluble Phosphate ◽

Plant Growth Promoting ◽

Growth Promoting ◽

Tomato Growth ◽

Phosphate Solubilizing

Pseudomonas simiae isolated from Seabuckthorn rhizosphere solubilized insoluble phosphate at 4-40ºC, pH 4-12 and in presence of 1-5% salt concentration. The optimum condition was observed at 28ºC, pH 6 and devoid of any salt stress. Ca3(PO4)2 was solubilized to a great extent than FePO4 and AlPO4. The isolate possess plant growth promoting attributes such as IAA (32 mg l-1), siderophore (78%) and HCN (0.1 OD at A625) production. Seed bacterization resulted in 30% and 51% enhanced shoot and root length, respectively in tomato seedling. Pot experiments revealed enhanced plant growth in P. simiae treated plants in both green shade net and open field conditions. Fruit yield was 9.8% and 19.8% higher over control in open and shade net condition, respectively.

Download Full-text

Plant Growth-Promoting Rhizobacteria (PGPR) for the Mitigation of Salt Stress and Growth Promotion of Chickpea

Microbial Mitigation of Stress Response of Food Legumes ◽

10.1201/9781003028413-18 ◽

2020 ◽

pp. 177-190

Author(s):

Kusum Sharma ◽

Senthilkumar Murugesan

Keyword(s):

Salt Stress ◽

Plant Growth ◽

Growth Promotion ◽

Plant Growth Promoting Rhizobacteria ◽

Plant Growth Promoting ◽

Growth Promoting

Download Full-text

Complete Genome Sequence of the Plant Growth-Promoting Bacterium Hartmannibacter diazotrophicus Strain E19T

International Journal of Genomics ◽

10.1155/2019/7586430 ◽

2019 ◽

Vol 2019 ◽

pp. 1-12 ◽

Cited By ~ 2

Author(s):

Christian Suarez ◽

Stefan Ratering ◽

Torsten Hain ◽

Moritz Fritzenwanker ◽

Alexander Goesmann ◽

...

Keyword(s):

Salt Stress ◽

Plant Growth ◽

Genome Sequence ◽

Plant Growth Promotion ◽

Complete Genome Sequence ◽

Complete Genome ◽

Growth Promotion ◽

Acc Deaminase ◽

Plant Growth Promoting ◽

Growth Promoting

Strain E19T described as Hartmannibacter diazotrophicus gen. nov. sp. nov. was isolated from the rhizosphere of Plantago winteri from a natural salt meadow in a nature protection area. Strain E19T is a plant growth-promoting rhizobacterium able to colonize the rhizosphere of barley and to promote its growth only under salt stress conditions. To gain insights into the genetic bases of plant growth promotion and its lifestyle at the rhizosphere under salty conditions, we determined the complete genome sequence using two complementary sequencing platforms (Ilumina MiSeq and PacBio RSII). The E19T genome comprises one circular chromosome and one plasmid containing several genes involved in salt adaptation and genes related to plant growth-promoting traits under salt stress. Based on previous experiments, ACC deaminase activity was identified as a main mechanism of E19T to promote plant growth under salt stress. Interestingly, no genes classically reported to encode for ACC deaminase activity are present. In general, the E19T genome provides information to confirm, discover, and better understand many of its previously evaluated traits involved in plant growth promotion under salt stress. Furthermore, the complete E19T genome sequence helps to define its previously reported unclear 16S rRNA gene-based phylogenetic affiliation. Hartmannibacter forms a distinct subcluster with genera Methylobrevis, Pleomorphomonas, Oharaeibacter, and Mongoliimonas subclustered with genera belonging to Rhizobiales.

Download Full-text