Protection of Photosynthesis by Halotolerant Staphylococcus sciuri ET101 in Tomato (Lycoperiscon esculentum) and Rice (Oryza sativa) Plants During Salinity Stress: Possible Interplay Between Carboxylation and Oxygenation in Stress Mitigation

Frontiers in Microbiology ◽

10.3389/fmicb.2020.547750 ◽

2021 ◽

Vol 11 ◽

Author(s):

Zarin Taj ◽

Dinakar Challabathula

Keyword(s):

Oryza Sativa ◽

Salt Stress ◽

Plant Growth ◽

Salinity Stress ◽

Stress Conditions ◽

Tomato Plants ◽

Rice Plants ◽

Atp Levels ◽

Ros Accumulation

Tomato (Lycoperiscon esculentum) and rice (Oryza sativa) are the two most important agricultural crops whose productivity is severely impacted by salinity stress. Soil salinity causes an irreversible damage to the photosynthetic apparatus in plants at all developmental stages leading to significant reduction in agricultural productivity. Reduction in photosynthesis is the primary response that is observed in all glycophytic plants during salt stress. Employment of salt-tolerant plant growth-promoting bacteria (PGPB) is an economical and viable approach for the remediation of saline soils and improvement of plant growth. The current study is aimed towards investigating the growth patterns and photosynthetic responses of rice and tomato plants upon inoculation with halotolerant PGPB Staphylococcus sciuri ET101 under salt stress conditions. Tomato and rice plants inoculated with PGPB showed increased growth rate and stimulated root growth, along with higher transpiration rates (E), stomatal conductance (gs), and intracellular CO2 accumulation (Ci). Additionally, correlation of relative water content (RWC) to electrolyte leakage (EL) in tomato and rice plants showed decreased EL in inoculated plants during salt stress conditions, along with higher proline and glycine betaine content. Energy dissipation by non-photochemical quenching (NPQ) and increased photorespiration of 179.47% in tomato and 264.14% in rice plants were observed in uninoculated plants subjected to salinity stress. Furthermore, reduced photorespiration with improved salinity tolerance is observed in inoculated plants. The higher rates of photosynthesis in inoculated plants during salt stress were accompanied by increased quantum efficiency (ΦPSII) and maximum quantum yield (Fv/Fm) of photosystem II. Furthermore, inoculated plants showed increased carboxylation efficiency of RuBisCO, along with higher photosynthetic electron transport rate (ETR) (J) during salinity stress. Although the total cellular ATP levels are drastically affected by salt stress in tomato and rice plants along with increased reactive oxygen species (ROS) accumulation, the restoration of cellular ATP levels in leaves of inoculated plants along with decreased ROS accumulation suggests the protective role of PGPB. Our results reveal the beneficial role of S. sciuri ET101 in protection of photosynthesis and amelioration of salinity stress responses in rice and tomato plants.

Download Full-text

Role of Halotolerant Microbes in Plant Growth Promotion Under Salt Stress Conditions

Saline Soil-based Agriculture by Halotolerant Microorganisms ◽

10.1007/978-981-13-8335-9_10 ◽

2019 ◽

pp. 209-253 ◽

Cited By ~ 2

Author(s):

Zahir Ahmad Zahir ◽

Sajid Mahmood Nadeem ◽

Muhammad Yahya Khan ◽

Rana Binyamin ◽

Muhammad Rashid Waqas

Keyword(s):

Salt Stress ◽

Plant Growth ◽

Plant Growth Promotion ◽

Growth Promotion ◽

Stress Conditions

Download Full-text

Phenotypic Plasticity for Growth and Nutrient Uptake in Milk Thistle under Salt Stress: Modulatory Role of Soil Supplementations with Plant Growth Promoters

International Journal of Agriculture and Biology ◽

10.17957/ijab/15.1718 ◽

2021 ◽

Vol 25 (03) ◽

pp. 692-700

Author(s):

Noreen Zahra

Keyword(s):

Salt Stress ◽

Phenotypic Plasticity ◽

Plant Growth ◽

Salinity Stress ◽

Arid Zone ◽

Milk Thistle ◽

Growth Promoters ◽

Plant Growth Promoters ◽

Semi Arid

Salinity stress negatively affects key physiological phenomena in plants while plants show great variability and respond differentially for tolerance to salt stress. Usually, nutrients imbalances affect specific plant tissues and physiological processes which are requisite for normal plant growth and development. The aim of this two-year (2017 and 2018) simulated field study was to investigate phenotypic plasticity for growth, relative leaf water content (RLWC) and nutrient status in milk thistle [Silybum marianum (L.) Gaertn.] ecotypes and the potential role of soil supplementation with pre-optimized levels of plant growth promoters (PGPs) in modulating these attributes under control and salinity (12 dS/m) stress. Four ecotypes of milk thistle were collected from three ecologically distinct zones including Faisalabad (FSD) and Kalar Kahar (KK) – semi-arid zone, Gujranwala (GUJ) – hot semi-arid zone and Quetta (QTA) – cool semi-arid zone. The studied nutrients were nitrate-N, phosphate-P, sulfate-S, sodium (Na), potassium (K) and calcium (Ca). The soil supplemented PGPs, applied with irrigation water, were ascorbic acid (AsA), thiourea (TU) and moringa leaf extract (MLE) at 250 μM, 500 μM and 3%, respectively of soil moisture content at field capacity. Results indicated that soil supplementation of PGPs in the field conditions is a feasible approach for enhancing nutrient uptake of milk thistle ecotypes under salt stress, while the effect of salinity stress restricted the uptake of the studied nutrients and caused their imbalance. Although the salinity stress reduced shoot and root dry matter, RLWC and restricted the uptake of these nutrients irrespective of ecotypes, the levels of nitrate-N, phosphate-P, K, sulfate-S, Ca, and RWC contents increased more with the soil supplementation of AsA followed by MLE as compared to other soil supplements in both the study years. Among the ecotypes, QTA followed by KK and FSD ecotypes gained more dry weight with greater leaf RWC and higher tissue nutrient contents due to PGPs under salt stress. The principal component analysis and correlation data revealed the existence of distinct phenotypic plasticity in the milk thistle ecotypes for nutrient acquisition with soil supplementation of PGPs under salinity stress. To conclude, ecotypes from QTA and KK were more promising than the others while AsA and MLE were better soil supplements in improving shoot and root nutrients under salt stress. © 2021 Friends Science Publishers

Download Full-text

Accumulation of compatible solutes in rice (Oryza sativa L.) cultivars by inoculation of endophytic plant growth promoting bacteria to alleviate salt stress

Applied Biological Chemistry ◽

10.1186/s13765-021-00638-x ◽

2021 ◽

Vol 64 (1) ◽

Author(s):

Shamim Ahmed ◽

Tae-Young Heo ◽

Aritra Roy Choudhury ◽

Denver I. Walitang ◽

Jeongyun Choi ◽

...

Keyword(s):

Salt Stress ◽

Plant Growth ◽

Glycine Betaine ◽

Growth Parameters ◽

Compatible Solutes ◽

Stress Conditions ◽

Plant Growth Promoting Bacteria ◽

Salt Tolerant ◽

Rice Plants ◽

Rice Genotypes

AbstractSalinization of agricultural lands, particularly rice paddies, results in the drastic decline of crop yields. Soil salinization impacts the plant physiology by inducing salt stress which may leads to osmotic stress, ionic stress and water-related nutrient imbalance. These imbalances necessitate the need for plants to produce osmolytes including proline and glycine betaine. This study aimed to elucidate the dynamic changes in proline and glycine betaine accumulation modulated by the inoculation of Brevibacterium linens RS16 in salt-sensitive and moderately salt-tolerant rice plants under salt stress conditions. This study showed the interaction of four major factors including rice genotypes with differing tolerance to salt stress, length of exposure to salt stress, level of salt stress and effects of inoculation. Salt stress resulted in significant reduction in plant growth parameters with the salt-sensitive rice genotype (IR29) having a more significant growth reduction. Both the salt-sensitive and salt-tolerant rice genotypes increased in total proline and glycine betaine accumulation at 3 days and 10 days after subjecting under 50 mM and 150 mM salt stress conditions. A significant increase in proline and glycine betaine was observed in the salt-sensitive genotype after 10 days under 50 mM and 150 mM salt stress conditions. Inoculation of the rice genotypes with B. linens RS16 resulted in the improvement of plant growth parameters in both rice genotypes, and total proline and glycine betaine accumulation, especially in IR29. This study showed that proline and glycine betaine are compatible osmolytes of rice under salt stress, and that inoculation of rice genotypes with B. linens RS16 mediated salt tolerance through improvement of plant growth parameters and proline and glycine betaine accumulation in rice plants.

Download Full-text

Functional Role of NAC Transcription Factors in Stress Responses and Genetic Diversity of Rice Plants Grown under Salt Stress Conditions

10.3390/bdee2021-09532 ◽

2021 ◽

Author(s):

Mohamed A. El-Esawi

Keyword(s):

Genetic Diversity ◽

Transcription Factors ◽

Salt Stress ◽

Stress Responses ◽

Functional Role ◽

Stress Conditions ◽

Nac Transcription Factors ◽

Rice Plants

Download Full-text

Transcriptomic Analysis of Rice Plants Overexpressing PsGAPDH in Response to Salinity Stress

Genes ◽

10.3390/genes12050641 ◽

2021 ◽

Vol 12 (5) ◽

pp. 641

Author(s):

Hyemin Lim ◽

Hyunju Hwang ◽

Taelim Kim ◽

Soyoung Kim ◽

Hoyong Chung ◽

...

Keyword(s):

Salt Stress ◽

Abiotic Stress ◽

Salinity Stress ◽

Functional Enrichment ◽

Differentially Expressed ◽

Pathway Enrichment Analysis ◽

Sequencing Data ◽

Illumina Hiseq ◽

Rice Plants ◽

Significant Difference

In plants, glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is a main enzyme in the glycolytic pathway. It plays an essential role in glycerolipid metabolism and response to various stresses. To examine the function of PsGAPDH (Pleurotus sajor-caju GAPDH) in response to abiotic stress, we generated transgenic rice plants with single-copy/intergenic/homozygous overexpression PsGAPDH (PsGAPDH-OX) and investigated their responses to salinity stress. Seedling growth and germination rates of PsGAPDH-OX were significantly increased under salt stress conditions compared to those of the wild type. To elucidate the role of PsGAPDH-OX in salt stress tolerance of rice, an Illumina HiSeq 2000 platform was used to analyze transcriptome profiles of leaves under salt stress. Analysis results of sequencing data showed that 1124 transcripts were differentially expressed. Using the list of differentially expressed genes (DEGs), functional enrichment analyses of DEGs such as Gene Ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were performed. KEGG pathway enrichment analysis revealed that unigenes exhibiting differential expression were involved in starch and sucrose metabolism. Interestingly, trehalose-6-phosphate synthase (TPS) genes, of which expression was enhanced by abiotic stress, showed a significant difference in PsGAPDH-OX. Findings of this study suggest that PsGAPDH plays a role in the adaptation of rice plants to salt stress.

Download Full-text

Halotolerant Microbial Consortia for Sustainable Mitigation of Salinity Stress, Growth Promotion, and Mineral Uptake in Tomato Plants and Soil Nutrient Enrichment

Sustainability ◽

10.3390/su13158369 ◽

2021 ◽

Vol 13 (15) ◽

pp. 8369

Author(s):

Chintan Kapadia ◽

R. Z. Sayyed ◽

Hesham Ali El Enshasy ◽

Harihar Vaidya ◽

Deepshika Sharma ◽

...

Keyword(s):

Salt Stress ◽

Salinity Stress ◽

Dry Weight ◽

Stress Factors ◽

Microbial Consortia ◽

Soil Conditions ◽

Mineral Uptake ◽

Shoot Height ◽

Tomato Plants ◽

Secondary Roots

Salinity significantly impacts the growth, development, and reproductive biology of various crops such as vegetables. The cultivable area is reduced due to the accumulation of salts and chemicals currently in use and is not amenable to a large extent to avoid such abiotic stress factors. The addition of microbes enriches the soil without any adverse effects. The effects of microbial consortia comprising Bacillus sp., Delftia sp., Enterobacter sp., Achromobacter sp., was evaluated on the growth and mineral uptake in tomatoes (Solanum Lycopersicum L.) under salt stress and normal soil conditions. Salinity treatments comprising Ec 0, 2, 5, and 8 dS/m were established by mixing soil with seawater until the desired Ec was achieved. The seedlings were transplanted in the pots of the respective pH and were inoculated with microbial consortia. After sufficient growth, these seedlings were transplanted in soil seedling trays. The measurement of soil minerals such as Na, K, Ca, Mg, Cu, Mn, and pH and the Ec were evaluated and compared with the control 0 days, 15 days, and 35 days after inoculation. The results were found to be non-significant for the soil parameters. In the uninoculated seedlings’ (control) seedling trays, salt treatment significantly affected leaf, shoot, root dry weight, shoot height, number of secondary roots, chlorophyll, and mineral contents. While bacterized seedlings sown under saline soil significantly increased leaf (105.17%), shoot (105.62%), root (109.06%) dry weight, leaf number (75.68%), shoot length (92.95%), root length (146.14%), secondary roots (91.23%), and chlorophyll content (−61.49%) as compared to the control (without consortia). The Na and K intake were higher even in the presence of the microbes, but the beneficial effect of the microbe helps plants sustain in the saline environment. The inoculation of microbial consortia produced more secondary roots, which accumulate more minerals and transport substances to the different parts of the plant; thus, it produced higher biomass and growth. Results of the present study revealed that the treatment with microbial consortia could alleviate the deleterious effects of salinity stress and improve the growth of tomato plants under salinity stress. Microbial consortia appear to be the best alternative and cost-effective and sustainable approach for managing soil salinity and improving plant growth under salt stress conditions.

Download Full-text