scholarly journals Exploring Potential of Seed Endophytic Bacteria for Enhancing Drought Stress Resilience in Maize (Zea mays L.)

2022 ◽  
Vol 14 (2) ◽  
pp. 673
Author(s):  
Sulman Siddique ◽  
Muhammad Naveed ◽  
Muhammad Yaseen ◽  
Muhammad Shahbaz

Water scarcity is abiotic stress that is becoming more prevalent as a result of human activities, posing a threat to agriculture and food security. Recently, endophytic bacteria have been proven to reduce drought stress and increase crop productivity. Here, we explored the efficacy of seed endophytic bacteria in maize crops under water deficit conditions. For this purpose, twenty-seven endophytic bacteria have been isolated from three distinct maize cultivars seeds (Malka 2016, Sahiwal Gold and Gohar-19) and evaluated for desiccation tolerance of −0.18, −0.491, and −1.025 MPa induced by polyethylene glycol (PEG) 6000. The nine isolates were chosen on the basis of desiccation tolerance and evaluated for maize growth promotion and antioxidant activity under normal and drought conditions. Results showed that drought stress significantly decreased the growth of maize seedlings. However, isolates SM1, SM4, SM19, and SM23 significantly improved the root and shoot length, plant biomass, leaf area, proline content, sugar, and protein content under normal and drought conditions. Antioxidant enzymes were significantly decreased at p-value < 0.05 with inoculation of seed endophytic bacteria under drought conditions. However, further experiments of seed endophytic bacteria (SM1, SM4, SM19, and SM23) should be conducted to validate results.

2015 ◽  
Vol 76 (4) ◽  
pp. 350-359 ◽  
Author(s):  
Peyman Ashkavand ◽  
Masoud Tabari ◽  
Mehrdad Zarafshar ◽  
Ivana Tomášková ◽  
Daniel Struve

Abstract Drought is a significant factor limiting crop production in arid regions while hawthorns (Crataegus sp.) are an important component of such region’s forests. Therefore, treatments that increase hawthorn drought resistance may also increase transplanting success. Thus, the physiological and biochemical responses of hawthorn seedlings to a factorial combination of different concentrations of silica nanoparticles (SNPs at 0, 10, 50 and 100 mg L−1) and three soil moisture treatments (without stress, moderate stress and severe stress) were investigated. Seedlings were irrigated with one of the four concentrations of SNPs for 45 days before exposing them to drought stress. Photosynthesis parameters, malondialdehyde (MDA), relative water content (RWC), membrane electrolyte leakage (ELI) as well as chlorophyll, carotenoid, carbohydrate and proline content were determined. At the end of the experiment, positive effects by SNP pre-treatment on physiological indexes were observed during drought stress. Under drought conditions, the effect of SNPs on photosynthetic rate and stomatal conductance was evident. Although the SNPs increased plant biomass, xylem water potential and MDA content, especially under drought conditions, RWC and ELI were not affected by the SNP pre-treatments. Seedlings pre-treated with SNPs had a decreased carbohydrate and proline content under all water regimes, but especially so under drought. Total chlorophyll content and carotenoid content did not change among the treatments. Generally, the findings imply that SNPs play a positive role in maintaining critical physiological and biochemical functions in hawthorn seedlings under drought stress conditions. However, more studies are needed before the physiological and biochemical basis of induced drought resistance can be determined.


2021 ◽  
Author(s):  
Mark Paul Selda Rivarez ◽  
Elizabeth P. Parac ◽  
Shajara Fatima M. Dimasingkil ◽  
Eka Mirnia ◽  
Pablito M. Magdalita

Abstract The native plant microbiome is composed of diverse communities that influence its overall health, with some species known to promote plant growth and pathogen resistance. Here, we show the antibacterial and growth promoting activities of autoclaved culture metabolites (ACMs) from native endophytic bacteria (NEB) in a papaya cultivar that is tolerant to bacterial crown rot (BCR) caused by Erwinia mallotivora . Initially, bacterial colonization in recovering tissues of this cultivar was observed before onset of tissue regeneration or 'regrowth'. We further isolated and characterized these bacteria and were able to identify two culturable stem NEB under genera Kosakonia (EBW), related to Enterobacter , and Sphingomonas (EBY). We also identified root NEB (BN, BS and BT) under genus Bacillus . Inhibition assays indicated that ACMs from these NEB promptly (18-30h) and efficiently inhibited (60-65%) E. mallotivora proliferation in vitro. Interestingly, when ACMs from BN and EBW were inoculated in surface-sterilized papaya seeds, germination was variably retarded (20-60% reduction) depending on plant genotype, but plant biomass accumulation was significantly stimulated, at around two-fold increase. Moreover, greenhouse experiments show that ACMs from all isolates, especially EBW, significantly reduced BCR incidence and severity in susceptible genotype, at around two-fold. In general, our observations of pathogen antagonism, plant growth promotion leading to disease reduction by ACMs of native endophytic bacteria suggested its contribution to increased fitness of papaya and tolerance against the (re)emerging BCR disease.


2014 ◽  
Vol 2 (1) ◽  
pp. 51-54 ◽  
Author(s):  
Raminder Kaur ◽  
Avtar Singh ◽  
J Kang

Mycorrhizal fungi greatly enhanced the ability of plants to take up phosphorus and other nutrients those are relatively immobile and exist in low concentration in the soil solution. Fungi can be important in the uptake of other nutrients by the host plant. Zinc nutrition is most commonly reported as being influenced by the association, although uptake of copper (Cu) , iron, N, K, Ca and Mg has been reported to be enhanced. Water uptake may be improved by mycorrhizal association, making more resistant to drought condition. Often both water and nutrient uptake are higher in drought stressed mycorrhizal plants than in non mycorrhizal plants. The fungal strands are capable of altering the water potential of plants and can only alleviate moderate drought stress and in more severe drought conditions they become ineffective.


Plants ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 126
Author(s):  
Judit Barroso ◽  
Nicholas G. Genna

Russian thistle (Salsola tragus L.) is a persistent post-harvest issue in the Pacific Northwest (PNW). Farmers need more integrated management strategies to control it. Russian thistle emergence, mortality, plant biomass, seed production, and crop yield were evaluated in spring wheat and spring barley planted in 18- or 36-cm row spacing and seeded at 73 or 140 kg ha−1 in Pendleton and Moro, Oregon, during 2018 and 2019. Russian thistle emergence was lower and mortality was higher in spring barley than in spring wheat. However, little to no effect of row spacing or seeding rate was observed on Russian thistle emergence or mortality. Russian thistle seed production and plant biomass followed crop productivity; higher crop yield produced higher Russian thistle biomass and seed production and lower crop yield produced lower weed biomass and seed production. Crop yield with Russian thistle pressure was improved in 2018 with 18-cm rows or by seeding at 140 kg ha−1 while no effect was observed in 2019. Increasing seeding rates or planting spring crops in narrow rows may be effective at increasing yield in low rainfall years of the PNW, such as in 2018. No effect may be observed in years with higher rainfall than normal, such as in 2019.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Mohamed S. Sheteiwy ◽  
Dina Fathi Ismail Ali ◽  
You-Cai Xiong ◽  
Marian Brestic ◽  
Milan Skalicky ◽  
...  

Abstract Background The present study aims to study the effects of biofertilizers potential of Arbuscular Mycorrhizal Fungi (AMF) and Bradyrhizobium japonicum (B. japonicum) strains on yield and growth of drought stressed soybean (Giza 111) plants at early pod stage (50 days from sowing, R3) and seed development stage (90 days from sowing, R5). Results Highest plant biomass, leaf chlorophyll content, nodulation, and grain yield were observed in the unstressed plants as compared with water stressed-plants at R3 and R5 stages. At soil rhizosphere level, AMF and B. japonicum treatments improved bacterial counts and the activities of the enzymes (dehydrogenase and phosphatase) under well-watered and drought stress conditions. Irrespective of the drought effects, AMF and B. japonicum treatments improved the growth and yield of soybean under both drought (restrained irrigation) and adequately-watered conditions as compared with untreated plants. The current study revealed that AMF and B. japonicum improved catalase (CAT) and peroxidase (POD) in the seeds, and a reverse trend was observed in case of malonaldehyde (MDA) and proline under drought stress. The relative expression of the CAT and POD genes was up-regulated by the application of biofertilizers treatments under drought stress condition. Interestingly a reverse trend was observed in the case of the relative expression of the genes involved in the proline metabolism such as P5CS, P5CR, PDH, and P5CDH under the same conditions. The present study suggests that biofertilizers diminished the inhibitory effect of drought stress on cell development and resulted in a shorter time for DNA accumulation and the cycle of cell division. There were notable changes in the activities of enzymes involved in the secondary metabolism and expression levels of GmSPS1, GmSuSy, and GmC-INV in the plants treated with biofertilizers and exposed to the drought stress at both R3 and R5 stages. These changes in the activities of secondary metabolism and their transcriptional levels caused by biofertilizers may contribute to increasing soybean tolerance to drought stress. Conclusions The results of this study suggest that application of biofertilizers to soybean plants is a promising approach to alleviate drought stress effects on growth performance of soybean plants. The integrated application of biofertilizers may help to obtain improved resilience of the agro ecosystems to adverse impacts of climate change and help to improve soil fertility and plant growth under drought stress.


2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Jose J. De Vega ◽  
Abel Teshome ◽  
Manfred Klaas ◽  
Jim Grant ◽  
John Finnan ◽  
...  

Abstract Background Miscanthus is a commercial lignocellulosic biomass crop owing to its high biomass productivity, resilience and photosynthetic capacity at low temperature. These qualities make Miscanthus a particularly good candidate for temperate marginal land, where yields can be limited by insufficient or excessive water supply. Differences in response to water stress have been observed among Miscanthus species, which correlated to origin. In this study, we compared the physiological and molecular responses among Miscanthus species under excessive (flooded) and insufficient (drought) water supply in glasshouse conditions. Results A significant biomass loss was observed under drought conditions in all genotypes. M. x giganteus showed a lower reduction in biomass yield under drought conditions compared to the control than the other species. Under flooded conditions, biomass yield was as good as or better than control conditions in all species. 4389 of the 67,789 genes (6.4%) in the reference genome were differentially expressed during drought among four Miscanthus genotypes from different species. We observed the same biological processes were regulated across Miscanthus species during drought stress despite the DEGs being not similar. Upregulated differentially expressed genes were significantly involved in sucrose and starch metabolism, redox, and water and glycerol homeostasis and channel activity. Multiple copies of the starch metabolic enzymes BAM and waxy GBSS-I were strongly up-regulated in drought stress in all Miscanthus genotypes, and 12 aquaporins (PIP1, PIP2 and NIP2) were also up-regulated in drought stress across genotypes. Conclusions Different phenotypic responses were observed during drought stress among Miscanthus genotypes from different species, supporting differences in genetic adaption. The low number of DEGs and higher biomass yield in flooded conditions supported Miscanthus use in flooded land. The molecular processes regulated during drought were shared among Miscanthus species and consistent with functional categories known to be critical during drought stress in model organisms. However, differences in the regulated genes, likely associated with ploidy and heterosis, highlighted the value of exploring its diversity for breeding.


2007 ◽  
Vol 34 (7) ◽  
pp. 589 ◽  
Author(s):  
Tuan Ngoc Le ◽  
Cecilia K. Blomstedt ◽  
Jianbo Kuang ◽  
Jennifer Tenlen ◽  
Donald F. Gaff ◽  
...  

The desiccation tolerant grass Sporobolus stapfianus Gandoger can modulate cellular processes to prevent the imposition of irreversible damage to cellular components by water deficit. The cellular processes conferring this ability are rapidly attenuated by increased water availability. This resurrection plant can quickly restore normal metabolism. Even after loss of more than 95% of its total water content, full rehydration and growth resumption can occur within 24 h. To study the molecular mechanisms of desiccation tolerance in S. stapfianus, a cDNA library constructed from dehydration-stressed leaf tissue, was differentially screened in a manner designed to identify genes with an adaptive role in desiccation tolerance. Further characterisation of four of the genes isolated revealed they are strongly up-regulated by severe dehydration stress and only in desiccation-tolerant tissue, with three of these genes not being expressed at detectable levels in hydrated or dehydrating desiccation-sensitive tissue. The nature of the putative proteins encoded by these genes are suggestive of molecular processes associated with protecting the plant against damage caused by desiccation and include a novel LEA-like protein, and a pore-like protein that may play an important role in peroxisome function during drought stress. A third gene product has similarity to a nuclear-localised protein implicated in chromatin remodelling. In addition, a UDPglucose glucosyltransferase gene has been identified that may play a role in controlling the bioactivity of plant hormones or secondary metabolites during drought stress.


2010 ◽  
Vol 337 (1-2) ◽  
pp. 233-242 ◽  
Author(s):  
Jean-Francois Yvan Moutia ◽  
Salem Saumtally ◽  
Stijn Spaepen ◽  
Jos Vanderleyden

Agriculture ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 15
Author(s):  
Sy Dinh Nguyen ◽  
Thi Huyen Trang Trinh ◽  
Trung Dzung Tran ◽  
Tinh Van Nguyen ◽  
Hoang Van Chuyen ◽  
...  

Black pepper (Piper nigrum L.) is one of the most important crops and global demand continues to increase, giving it a high export value. However, black pepper cultivation has been seriously affected by a number of pathogenic diseases. Among them, “quick wilt” caused by Phytophthora sp., “slow decline” caused by Fusarium sp., and root-knot nematode Meloidogyne sp. have a serious negative effect on black pepper growth and productivity. There have been different chemical and biological methods applied to control these diseases, but their effectiveness has been limited. The aim of this research was to evaluate different combinations of rhizosphere bacteria and endophytic bacteria isolated from black pepper farms in the Central Highland of Vietnam for their ability to suppress pathogens and promote black pepper growth and yield. Formula 6, containing the strains Bacillus velezensis KN12, Bacillus amyloliquefaciens DL1, Bacillus velezensis DS29, Bacillus subtilis BH15, Bacillus subtilis V1.21 and Bacillus cereus CS30 exhibited the largest effect against Phytophthora and Fusarium in the soil and in the roots of black pepper. These bio-products also increased chlorophyll a and b contents, which led to a 1.5-fold increase of the photosynthetic intensity than the control formula and a 4.5% increase in the peppercorn yield (3.45 vs. 3.30 tons per hectare for the control). Our results suggest that the application of rhizosphere and endophytic bacteria is a promising method for disease control and growth-promotion of black pepper.


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