Bio-priming Of Seeds Research Articles

Biopriming of corn seeds based on Bacillus subtilis under different storage periods

Corn crop (Zea mays L.) is one of the pillars of Brazilian agriculture, with a wide cultivation area and high productivity; Brazil is the world's second largest exporter of this cereal. For this reason, the aim of the present study was to evaluate the viability of biopriming of corn seeds with a product based on Bacillus subtilis, at different concentrations, up to 120 days of storage. The research was carried out in the seed technology laboratory of the State University of Londrina (UEL), using the commercial corn seeds Balu 366. The experimental design was completely randomized, with four replications, in a 7 × 5 factorial scheme, with seven concentrations of the commercial product based on Bacillus subtilis (Serenade) for seed biopriming (0.0, 2.5, 5.0, 7.5, 10.0, 12.5, and 15.0 %) and five storage periods in a cold chamber (0, 30, 60, 90, and 120 days). The evaluation of the physiological quality of the seeds occurred through germination, cold and seedling length tests. The variables analyzed were first germination count, germination percentage, vigor from the cold test, shoot length, length of the longest root, shoot dry mass, and root dry mass. For the statistical analysis, adjustments of regression models with the best fit were made. The biopriming of seeds proved to be an advantageous practice to enhance the physiological quality of the seeds under storage; it should be carried out at a concentration of 2.5 %, due to its economic viability, considering its efficiency equivalent to the highest concentrations. The biopriming of seeds proved to be a viable practice for seed storage for up to 60 days.

Effect of Seed Biopriming on Growth, Yield and Economics of Rabi Green Gram (Vigna radiata L.) in Rainfed Condition of Balasore District of Odisha

Effect of Seed Biopriming on Growth, Yield and Economics of Rabi Green Gram (Vigna radiata L.) in Rainfed Condition of Balasore District of Odisha

Exploring the Mycovirus Sclerotinia sclerotiorum Hypovirulence-Associated DNA Virus 1 as a Biocontrol Agent of White Mold Caused by Sclerotinia sclerotiorum.

Sclerotinia sclerotiorum is a necrotrophic fungal pathogen causing white mold on many important economic crops. Recently, some mycoviruses such as S. sclerotiorum hypovirulence-associated DNA virus 1 (SsHADV-1) converted S. sclerotiorum into a beneficial symbiont that helps plants manage pathogens and other stresses. To explore the potential use of SsHADV-1 as a biocontrol agent in the United States and to test the efficacy of SsHADV-1-infected United States isolates in managing white mold and other crop diseases, SsHADV-1 was transferred from the Chinese strain DT-8 to United States isolates of S. sclerotiorum. SsHADV-1 is readily transmitted horizontally among United States isolates of S. sclerotiorum and consistently conferred hypovirulence to its host strains. Biopriming of dry bean seeds with hypovirulent S. sclerotiorum strains enhanced resistance to white mold, gray mold, and Rhizoctonia root rot. To investigate the underlying mechanisms, endophytic growth of hypovirulent S. sclerotiorum in dry beans was confirmed using PCR, and the expression of 12 plant defense-related genes were monitored before and after infection. The results indicated that the endophytic growth of SsHADV-1-infected strains in plants stimulated the expression of plant immunity pathway genes that assisted a rapid response from the plant to fungal infection. Finally, application of the seed biopriming technology with SsHADV-1-infected hypervirulent strain has promise for the biological control of several diseases of wheat, pea, and sunflower.

Effect of Seed Biopriming on Germination & Seedling Attributes in Chickpea (Cicer arietinum L.)

The Study was conducted during Zaid season of 2022-2023 with IPC-05-59 genotype of chickpea (Cicer arietinum L.) Find out the Effect of seed biopriming on germination & seedling attributes in chickpea (Cicer arietinum L). The design of experiment was Completely Randomized Design comprising treatments [viz.T0-uninoculatedT1-Bacillus sp, T2- Mesorhizobium sp., T3- Pseudomonas sp, T4- Bacillus sp(0.5)+ Mesorhizobium sp.(0.5),T5- Pseudomonas sp.(0.5)+ Mesorhizobium sp.(0.5), T6- Bacillus sp.(0.5)+Pseudomonas sp(0.5).+ Mesorhizobium sp.(0.5), T7- Bacillus sp,T8- Mesorhizobium sp, T9- Pseudomonas sp, T10- Bacillus sp.(0.5) + Mesorhizobium sp(0.5),T11-Pseudomonas sp. (0.5)+ Mesorhizobiumsp(0.5),T12- Bacillus sp.(0.5) + Pseudomonas sp. (0.5) + Mesorhizobium sp. (0.5) . The treated seeds along with control were evaluated for their morpho-physiological, growth, yield, root parameters and biochemical parameters under laboratory conditions, The study revealed that seeds biopriming techniques with Bacillus sp.(0.5)+ Pseudomonas sp(0.5).+ Mesorhizobium sp.(0.5) concentration @ 1.0ml for 1 hours T6 recorded significantly higher germination percent (93%), rate of germination (5.38), mean germination time (11.16), root length (11.73cm),shoot length(13.27cm),seedling length(25.00cm), fresh weight (7.91gm),dry weight (1.62gm), vigor index-I (2324.91), vigor index – II (135.82), seed density (1.27), electrical conductivity (0.817), seed metabolic efficiency (1.018). which was followed by seedprimingwithT12- Bacillus sp (0.5) +Pseudomonas sp (0.5) +Mesorhizobium sp (0.5) @ 1.5ml for 2 hours and minimum was recorded in T0 (control).

Enhancing germination percentage and seed vigor in horticultural Crops through biopriming techniques

Seed biopriming induces a physiological condition that promotes germination and uniform seedling emergence. An investigation is carried out on different seeds such as carrot (Daucus carota subsp. Sativus), onion (Allium cepa L.), cauliflower (Brassica oleracea), radish, (Raphanus sativus), tomato (Solanum lycopersicum), spinach (Spinacia oleracea), fenugreek (Trigonella foenum-graecum), and pea (Pisum sativum) to standardise bio-priming with Bacillus siamensis strain NKIT-9 to improve seed germination and seedling vigor index. To optimise the concentration of bio-priming seedlings were bioprimed overnight with Bacillus siamensis strain (NKIT-9) at varied concentrations (0.1mg/ml, 10µg/ml, 0.1µg/ml, and 10ng/ml). Bio-priming with Bacillus siamensis strain NKIT-9 gave highest values of germination percentage and seedling vigor index of carrot (at 0.1mg/ml), onion (at 0.1µg/ml ), cauliflower at 0.1mg/ml, 10µg/ml, and 0.1µg/ml), radish (at0.1mg/ml and 0.1µg/ml), tomato (at 0.1mg/ml), spinach (at 10ng/ml ), fenugreek (at 10ng/ml) and pea (a10ng/ml ) as compared with control. carrot, onion, cauliflower, radish, tomato, spinach, fenugreek, and pea exhibited higher germination percentages (60%, 100%, 100%, 100%, 80%, 90%, 100%, and 60% respectively) and seedling vigor indexes (148 ,720, 910, 880, 525, 580, 990, and 1018 respectively) when compared with control. Therefore, bio-priming with these concentrations is best suited for improving germination rate and seedling vigor of seeds.

Assessing the Different Bio-priming Methods and Knowledge Dissemination through On Farm Trial in Salem District

One of the most important pre sowing seed improvement techniques for managing biotic and abiotic challenges is seed bio-priming, which ensures uniform stand establishment under adverse conditions. "Bio-priming" seed treatment combines biological (inoculating seeds with protective organisms) and physiological (hydrating seeds) components of vigour improvement, disease management. Recently, it has been employed as an alternate technique for not only to eradicate numerous soil- and seed-borne diseases but also improves the field establishment and vigour. In the current study, an On-Farm Trial bhendi seeds were soaked with two biopriming treatments Viz., (i) 10% Pseudomonas fluorecens, (ii) 10% Trichoderma viridi, for 6 hours followed by shade drying and sown in farmers' fields during kharif, 2020. Untreated seeds served as the control. The findings showed that 10% Pseudomonas fluorescens outperformed than Trichoderma and untreated seed in terms of yield (172.5 q/ha), net return (Rs. 2,58,750/ha), and benefit-cost ratio (2.59), The 10% Trichoderma primed seeds, which was the next-best treatment, had high yields, net returns, and BCR values of 169.8q/ha, Rs. 2,54,700/ha, and 2.56 respectively. So, it was concluded that bioprimingof seeds with 10% Pseudomonas fluorescens for six hours increased the production of bhendi. The dissemination of extension activities like training and method demonstration increased the understanding of farmers about biopriming from 5.4 to 52.5 percent.

Reduction of Salinity Stress in Wheat through Seed Bio-Priming with Mycorrhiza and Growth-Promoting Bacteria and its Effect on Physiological Traits and Plant Antioxidant Activity with Silicon Nanoparticles Application

Reduction of Salinity Stress in Wheat through Seed Bio-Priming with Mycorrhiza and Growth-Promoting Bacteria and its Effect on Physiological Traits and Plant Antioxidant Activity with Silicon Nanoparticles Application

Characterization of the Seed Biopriming, Plant Growth-Promoting and Salinity-Ameliorating Potential of Halophilic Fungi Isolated from Hypersaline Habitats.

Salinity stress is one of the major abiotic factors limiting crop yield in arid and semi-arid regions. Plant growth-promoting fungi can help plants thrive in stressful conditions. In this study, we isolated and characterized 26 halophilic fungi (endophytic, rhizospheric, and soil) from the coastal region of Muscat, Oman, for plant growth-promoting activities. About 16 out of 26 fungi were found to produce IAA, and about 11 isolates (MGRF1, MGRF2, GREF1, GREF2, TQRF4, TQRF5, TQRF5, TQRF6, TQRF7, TQRF8, TQRF2) out of 26 strains were found to significantly improve seed germination and seedling growth of wheat. To evaluate the effect of the above-selected strains on salt tolerance in wheat, we grew wheat seedlings in 150 mM, 300 mM NaCl and SW (100% seawater) treatments and inoculated them with the above strains. Our findings showed that fungal strains MGRF1, MGRF2, GREF2, and TQRF9 alleviate 150 mM salt stress and increase shoot length compared to their respective control plants. However, in 300 mM stressed plants, GREF1 and TQRF9 were observed to improve shoot length. Two strains, GREF2 and TQRF8, also promoted plant growth and reduced salt stress in SW-treated plants. Like shoot length, an analogous pattern was observed in root length, and different salt stressors such as 150 mM, 300 mM, and SW reduced root length by up to 4%, 7.5%, and 19.5%, respectively. Three strains, GREF1, TQRF7, and MGRF1, had higher catalase (CAT) levels, and similar results were observed in polyphenol oxidase (PPO), and GREF1 inoculation dramatically raised the PPO level in 150 mM salt stress. The fungal strains had varying effects, with some, such as GREF1, GREF2, and TQRF9, showing a significant increase in protein content as compared to their respective control plants. Under salinity stress, the expression of DREB2 and DREB6 genes was reduced. However, the WDREB2 gene, on the other hand, was shown to be highly elevated during salt stress conditions, whereas the opposite was observed in inoculated plants.

Seed bio-priming with phosphate-solubilizing bacteria strains to improve rice (Oryza sativa L. var. FARO 44) growth under ferruginous ultisol conditions.

This study investigated the possibility of using phosphate-solubilizing bacteria (PSB) with plant-growth-promoting (PGP) capabilities to improve the growth properties of rice plants under ferruginous ultisol (FU) conditions through bio-priming. The following PSB with PGP properties were used in this study: Bacillus cereus strain GGBSU-1, Proteus mirabilis strain TL14-1, and Klebsiella variicola strain AUH-KAM-9, which were previously isolated and characterized based on 16S rRNA gene sequencing. Biosafety analysis of the PSB isolates was conducted using blood agar. The rice seeds were then bio primed with the PSB for 3, 12, and 24 h and then sown in a composite FU soil sample. Differences in germinat ion bioassay were investigated 15 weeks after bio-priming using scanning electron microscopy (SEM), morphology, physiology, and biomass parameters. The composite FU soil used in this study had high pH, low bioavailable phosphorus, low water-holding capacity, and high iron levels, which resulted in low growth properties of rice seeds without bio-priming in the FU soil. Germination parameters were improved in seeds bio primed with the PSB, especially after 12 h of priming, compared with seeds without priming. SEM showed higher bacterial colonization in bio primed seeds. Bio-priming of rice seeds with the studied PSB under FU soil conditions significantly improved seed microbiome, rhizocolonization, and soil nutrient properties, thereby enhancing the growth properties of rice. This indicated the ability of PSB to solubilize and mineralize soil phosphate and improve phosphorus availability and soil properties for optimum plant usage in phosphate-stressed and iron toxic soils.

Effect of seed biopriming with selected endophytes on the growth and chilling tolerance of rice plants.

The aim of this study was to develop an efficient bioinoculant for amelioration of adverse effects from chilling stress (10°C), which are frequently occurred during rice seedling stage. Seed germination bioassay under chilling condition with rice (Oryza sativa L.) cv. Tainan 11 was performed to screen for plant growth-promoting (PGP) bacteria among 41 chilling-tolerant rice endophytes. And several agronomic traits were used to evaluate the effects of bacterial inoculation on rice seedling, which were experienced for 7-d chilling stress in walk-in growth chamber. The field trials were further used to verify the performance of potential PGP endophytes on rice growth. A total of three endophytes with multiple PGP traits were obtained. It was demonstrated that Pseudomonas sp. CC-LS37 inoculation led to 18% increase of maximal efficiency of Photosystem II (PSII) after 7-d chilling stress and 7% increase of chlorophyll a content, and 64% decline of malondialdehyde content in shoot after 10-d recovery at normal temperature in walk-in growth chamber. In field trial, biopriming of seeds with strain CC-LS37 caused rice plants to increase shoot chlorophyll soil plant analysis development values (by 2.9% and 2.5%, respectively) and tiller number (both by 61%) under natural climate and chilling stress during the end of tillering stage, afterward 30% more grain yield was achieved. In conclusion, strain CC-LS37 exerted its function in increase of tiller number of chilling stress-treated rice seedlings via improvement of photosynthetic characteristics, which in turn increases the rice grain yield. This study also proposed multiple indices used in the screening of potential endophytes for conferring chilling tolerance of rice plants.

Seed Biopriming by Endophytes for Enhanced Field Performance of Hybrid Maize (Zea mays L.) COH(M) 8

Background: Endophytes are generally defined as symptomless fungal or bacterial microorganisms, which are associated with their host plants by colonizing the internal plant parts, which has made them as a valuble tool in improving crop performance in agriculture. With this view, the study was conducted to assess the efficacy of endophytes when used as seed biopriming agent on plant growth and seed yield of hybrid maize COH(M) 8 under field conditions during 2021-2022. Methods: The present study was carried out with different endophytic seed priming for 12 hrs duration at the ratio of 1:1 volume/volume with Beauveria bassiana @ 5%, Metarhizium anisopliae @ 5% and Bacillus subtilis @ 8% along with hydro priming and untreated control combined with foliar spray at 30th and 50th days after sowing (DAS). Result: The results revealed that among various endophytes used in this study, M. anisopliae @ 5% when used for biopriming of seeds as well as for foliar spraying @ 0.5% maximized the plant height (208.4 cm @ 45 DAS and 247.8 cm @ 75 DAS), leaf length (76.0 cm) chlorophyll (chl) content (chl a 0.423 mg/g, chl b 0.229 mg/g and total chl 0.652 mg/g), cob length (21.2 cm), seed yield/plot (6.89 kg) and seed yield/ha (5744 kg).

Effects of Seed Bio-Priming by Purple Non-Sulfur Bacteria (PNSB) on the Root Development of Rice.

The effects of seed bio-priming (seed soaking) with purple non-sulfur bacteria (PNSB) on the grain productivity and root development of rice were examined by a field study and laboratory experiments, respectively. Two PNSB strains, Rhodopseudomonas sp. Tsuru2 and Rhodobacter sp. Tsuru3, isolated from the paddy field of the study site were used for seed bio-priming. For seed bio-priming in the field study, the rice seeds were soaked for 1 day in water containing a 1 × 105 colony forming unit (cfu)/mL of PNSB cells, and the rice grain productivities at the harvest time were 420, 462 and 504 kg/are for the control, strain Tsuru2-primed, and strain Tsuru3-primed seeds, respectively. The effects of seed priming on the root development were examined with cell pot cultivation experiments for 2 weeks. The total root length, root surface area, number of tips and forks were evaluated with WinRhizo, an image analysis system, and strains Tsuru2- and Tsuru3-primed seeds showed better root development than the control seeds. The effects of seed priming with the dead (killed) PNSB cells were also examined, and the seed priming with the dead cells was also effective, indicating that the effects were attributed to some cellular components. We expected the lipopolysaccharide (LPS) of PNSB as the effective component of PNSB and found that seed priming with LPS of Rhodobacter sphaeroides NBRC 12203 (type culture) at the concentrations of 5 ng/mL and 50 ng/mL enhanced the root development.

Warhorses in soil bioremediation: Seed biopriming with PGPF secretome to phytostimulate crop health under heavy metal stress

The fungal symbiosis with the plant root system is importantly recognized as a plant growth promoting fungi (PGPFs), as well as elicitor of plant defence against different biotic and abiotic stress conditions. Thus PGPFs are playing as a key trouper in enhancing agricultural quality and increased crop production and paving a way towards a sustainable agriculture. Due to increased demand of food production, the over and unscientific usage of chemical fertilizers has led to the contamination of soil by organic and inorganic wastes impacting on soil quality, crops quality effecting on export business of agricultural products. The application of microbial based consortium like plant growth promoting fungi is gaining worldwide importance due to their multidimensional activity. These activities are through plant growth promotion, induction of systemic resistance, disease combating and detoxification of organic and inorganic toxic chemicals, a heavy metal tolerance ability. The master key behind these properties exhibited by PGPFs are attributed towards various secretory biomolecules (secondary metabolites or enzymes or metabolites) secreted by the fungi during interaction mechanism. The present review is focused on the multidimensional role PGPFs as elicitors of Induced systemic resistance against phytopathogens as well as heavy metal detoxifier through seed biopriming and biofortification methods. The in-sights on PGPFs and their probable mechanistic nature contributing towards plants to withstand heavy metal stress and stress alleviation by activating of various stress regulatory pathways leading to secretion of low molecular weight compounds like organic compounds, glomalin, hydrophobins, etc,. Thus projecting the importance of PGPFs and further requirement of research in developing PGPFs based molecules and combining with trending Nano technological approaches for enhanced heavy metal stress alleviations in plant and soil as well as establishing a sustainable agriculture.

Economic Evaluation of the Effect of S Fertilization with Seed Biopriming on Indian Mustard (cv. Giriraj) Production under Middle Gangetic Plains of Uttar Pradesh, India

A two-year field experiment was carried out during rabi season of 2018-19 and 2019-20 at the research farm, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi on a sandy loam soil to evaluate the economic feasibility of seed bio-priming with sulphur (S) fertilization for mustard production in middle gangetic plains. The experiment was laid out in randomized block design (RBD) with three replications. The treatments were consisting of four levels of S (0, 20, 30 and 40 kg S ha-1) through bentonite S and three seed priming sources (un-primed, Bacillus subtilis and Pseudomonas fluorescence). The results showed that, application of T11 (40 kg S ha-1 + Bacillus subtilis) results in highest gross return (105791 and 116209 INR ha-1), net return (70182 and 79282 INR ha-1) and B: C ratio (1.97 and 2.15) in the first and second year of study, respectively. Application of 30 kg S ha-1 + Bacillus subtilis gives higher gross return, net return and B: C ratio compared to application of 40 kg S ha-1 (recommended dose of S) without seed bio-priming. It was concluded that application of 40 kg S ha-1 + Bacillus subtilis was best technique for better net return in mustard production and may be recommended to farmers.

Understanding Heat and Drought Stress Adaptation Mechanisms in Wheat: A Combined Approach

Drought and heat are the key environmental stressors significantly decreasing wheat productivity (86 and 69%, respectively) and weakening food security in the major wheat growing regions worldwide. Wheat crops have regularly experienced combined (Heat+Drought) stress in the field and the joint effects are more detrimental to wheat growth than the effects of each stress separately.Drought and heat stress have shown synergistic, antagonistic, or hypo-additive impacts on growth, grain filling, and yield parameters when combined. In order to escape and/or tolerate these unfavorable environmental conditions, wheat has developed advancedresponses at various levels. This review explores how physiological, morphological, biochemical and molecular traits work together to provide tolerance to coupled stresses. Importance of specific traits such as, canopy temperature, assimilate partitioning and water use efficiency along with reproductive traitswhich provide tolerance against these combined stressors has also been explained. This review also highlighted the potential of altered agronomic practices, application of micronutrients, biopriming of seeds (endophytes) against abiotic stresses. Further emphasize has been given to promising novel technologies like, genome editing (CRISPR),identification of novel QTL’s and alleles to improve both heat and drought tolerance for sustainable wheat production.

Biopriming of maize seeds with plant growth-promoting bacteria isolated from the earthworm Aporrectodea molleri: effect on seed germination and seedling growth.

Earthworms have become a potential source of multi-beneficial bacteria and effective bioinoculants. Seed biopriming is an efficient inoculation method to apply bacteria prior to sowing, which enhances the chances of bacterial candidates to colonize the rhizosphere and/or establish a liaison with the plant. In this study, we evaluated plant growth-promoting traits of bacterial strains isolated from the earthworm's Aporrectodea molleri chloragogenous tissue. In addition, we investigated their prospective use as biopriming agents to enhance Zea mays germination and seedling growth. Results were subjected to principal component analysis for potential correlations between the studied parameters. The bacterial strains displayed different in vitro plant growth-promoting characteristics and were efficient when applied in vivo as they significantly increased maize germination rate (26-78%), root elongation (67-84%), seedlings fresh weight and dry weight. Aeromonas encheleia TC22 was the most significant strain to influence germination due to its high ability to produce indole-3-acetic acid, and along with Pseudomonas azotoformans TC1, they were the most proficient at enhancing seedling root elongation and biomass, which was significantly correlated with their in vitro plant growth-promoting traits. Our findings indicate that isolates TC22 and TC1 are potent bio-primers for maize seeds and should be tested further for their use as biopriming inoculants.

Biopriming of Maize Seeds with a Novel Bacterial Strain SH-6 to Enhance Drought Tolerance in South Korea

Maize is the third most common cereal crop worldwide, after rice and wheat, and plays a vital role in preventing global hunger crises. Approximately 50% of global crop yields are reduced by drought stress. Bacteria as biostimulants for biopriming can improve yield and enhance sustainable food production. Further, seed biopriming stimulates plant defense mechanisms. In this study, we isolated bacteria from the rhizosphere of Artemisia plants from Pohang beach, Daegu, South Korea. Twenty-three isolates were isolated and screened for growth promoting potential. Among them, bacterial isolate SH-6 was selected based on maximum induced tolerance to polyethylene glycol-simulated drought. SH-6 showed ABA concentration = 1.06 ± 0.04 ng/mL, phosphate solubilizing index = 3.7, and sucrose concentration = 0.51 ± 0.13 mg/mL. The novel isolate SH-6 markedly enhanced maize seedling tolerance to oxidative stress owing to the presence of superoxide dismutase, catalase, and ascorbate peroxidase activities in the culture media. Additionally, we quantified and standardized the biopriming effect of SH-6 on maize seeds. SH-6 significantly increased maize seedling drought tolerance by up to 20%, resulting in 80% germination potential. We concluded that the novel bacterium isolate SH-6 (gene accession number (OM757882) is a biostimulant that can improve germination performance under drought stress.

Seed Quality Enhancement Through Seed Biopriming to Increase Productivity: A Review

Consistent agricultural production needs a package of methods starting from the improved crop varieties to agronomic practices to fulfil the food demand worldwide. Agricultural productivity is mainly restricted due to poor seed quality coupled with several biotic and abiotic stresses. Therefore, enhancement of agricultural production through improved quality of seed needs additional practice to achieve sustainable growth of farm income. In this context, biopriming could serve as a viable approach to enhance crop productivity as it improves the performance of plants under sub-optimal conditions. In biopriming, the bacterial inoculum is used during the imbibition process that bypasses the need for hazardous agrochemicals linked with crop management practices. The use of microbial solution on the planting material is an economically and environmentally safe method for uniform crop establishment. Alongside biotic stress amelioration, biopriming also serves as a viable solution to enhance the nutrient use efficiency in crop plants. Overall, the introduction of biopriming in agricultural practices allows farmers to achieve better production with a minimum investment of costly inputs.

Modulation of plant growth and antioxidative defense system through endophyte biopriming in cotton (Gossypium spp.) and non-host crops

Seed biopriming is very promising in improving seed health by mitigating various biotic and abiotic stresses. In this study, the effect of biopriming with cotton endophytes on seed germination and other growth parameters in host and non-host crops like wheat, sorghum, cowpea and chick pea was examined. The endophytes were antagonistic to cotton pathogens Corynespora cassiicola and Fusarium solani under in vitro. Among the eight endophytes, CFR-1 and CEL-48 were highly efficient with inhibition rates of 66.16% and 64.24% respectively against C. cassiicola, whereas CFL-34 was efficient against F. solani with more than 50% inhibition. Seed biopriming enhanced seed germination in cotton and non-host crops whereas seed vigor index was highest in bio-primed cotton. Moreover, growth promotion parameters were also enhanced upon endophyte biopriming. Total sugar content ranged from 5.46 to 7.54 mg/g F.W in cotton and highest was found in CFL-34 treated wheat (8.64 mg/g FW). There was an increase of 10–30% soluble protein in bioprimed cotton over control. Interestingly, the antioxidant potential in all the bio-primed crops was improved with increased catalase and peroxidase activity. Specific activity of catalase ranged from 0.42 to 1.90 μmol/min/mg protein in cotton, while highest activity was reported in CEL-48 primed wheat. The findings of this investigation emphasizes seed biopriming with endophytes for sustainable plant health management.

Bio-priming of seeds: Plant stress management and its underlying cellular, biochemical and molecular mechanisms

Exposure of crops to stress is the most significant barrier to agricultural output and food security worldwide. Stress induces changes in plants’ physiological functions, which leads to lower plant growth and agricultural yield. Plants undergo a variety of molecular, cellular, and physiological changes to combat various abiotic stresses. Plants suffer from increased osmotic pressure outside the root due to osmotic stresses like drought or salt stress that ultimately result in reduced water availability to plant roots. In addition to morphological modifications, physiological changes such as lower leaf osmotic potential, accumulation of osmoprotectants, increased antioxidant activities, and so on occur in response to such abiotic stresses. Seed priming is a novel yet simple technique that involves the use of beneficial and eco-friendly biological agents to improve the physiological functioning of seeds. This technique also plays a vital role in restoring agro-ecological balances through the improvement of soil fertility or by decreasing soil and water contamination. An understanding of the mechanisms involved in seed bio-priming with plant growth-promoting microbes is very crucial to efficiently utilise this technique towards agricultural sustainability. It is generally thought that the advancement of metabolic processes along with activation of repairing systems during the pre-germination stage are the central reasons behind growth promotion and acquired stress tolerance. The application of plant growth-promoting rhizobacteria in agriculture has been emerging to improve stress resilience. Bio-priming of seeds ensures early protein and DNA synthesis, and also helps in effective mitochondrial development. This review aims to summarise the current state of understanding of the mechanisms involved in this eco-friendly technique.