{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,29]],"date-time":"2026-01-29T03:40:05Z","timestamp":1769658005403,"version":"3.49.0"},"reference-count":48,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2026,1,28]],"date-time":"2026-01-28T00:00:00Z","timestamp":1769558400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Portuguese funds through Fundac\u00e3o para a Ci\u00eancia e a Tecnologia"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Resources"],"abstract":"<jats:p>Drought poses a major challenge for global agriculture, demanding strategies that improve crop resilience while safeguarding water and nutrient resources. Plant growth-promoting rhizobacteria (PGPR)-based biostimulants offer a sustainable approach to enhance resource-use efficiency under water-limited conditions. This study evaluated two commercial PGPR biostimulants applied to maize (Zea mays L.) and tomato (Solanum lycopersicum L.) seedlings grown under well-watered (80% field capacity) and water-stressed (40% field capacity) conditions. Both products improved plant growth and physiological performance, although responses were crop-specific. Inoculated tomato seedlings accumulated up to 35% more shoot biomass under optimal watering (1.6 g in non-inoculated seedlings compared with 2.5 g in inoculated seedlings), whereas maize maintained biomass production under drought, consistent with its higher intrinsic water-use efficiency, showing increases of approximately 50% (well-watered: 0.5 g versus 0.8 g; water-stressed: 0.3 g versus 0.7 g in non-inoculated and inoculated seedlings, respectively). Biostimulant application enhanced the acquisition and internal utilization of essential mineral resources, increasing leaf concentrations of (i) the macronutrients P (up to 300%), K (up to 70%), Mg (up to 220%), and Ca (up to 85%), and (ii) the micronutrients B (up to 400%), Fe (up to 260%), Mn (up to 240%), and Zn (up to 180%). Maximum nutrient increases were consistently observed in water-stressed maize seedlings inoculated with biostimulant 2. Antioxidant activities, particularly ascorbate peroxidase and catalase, increased by 20\u201340%, indicating more effective mitigation of oxidative stress. Principal component analysis revealed coordinated adjustments among growth, nutrient-use efficiency, and physiological traits in inoculated plants. Overall, PGPR-based biostimulants improved early drought tolerance and resource-use efficiency, supporting their potential as sustainable tools for climate-resilient agriculture. Field-scale studies remain necessary to confirm long-term agronomic benefits.<\/jats:p>","DOI":"10.3390\/resources15020020","type":"journal-article","created":{"date-parts":[[2026,1,28]],"date-time":"2026-01-28T15:04:46Z","timestamp":1769612686000},"page":"20","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Microbial Biostimulants Improve Early Seedling Resilience to Water Stress"],"prefix":"10.3390","volume":"15","author":[{"given":"Juliana","family":"Melo","sequence":"first","affiliation":[{"name":"cE3c\u2014Centre for Ecology, Evolution and Environmental Changes, CHANGE\u2014Global Change and Sustainability Institute, Faculdade de Ci\u00eancias, Universidade de Lisboa, Edif\u00edcio C2, Piso 5, Sala 2.5.46, Campo Grande, 1749-016 Lisboa, Portugal"},{"name":"Soilvitae Lda., Rua Espir\u00edto Santo, n\u00ba 18, 6060-071 Idanha-A-Nova, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5421-4763","authenticated-orcid":false,"given":"Teresa","family":"Dias","sequence":"additional","affiliation":[{"name":"cE3c\u2014Centre for Ecology, Evolution and Environmental Changes, CHANGE\u2014Global Change and Sustainability Institute, Faculdade de Ci\u00eancias, Universidade de Lisboa, Edif\u00edcio C2, Piso 5, Sala 2.5.46, Campo Grande, 1749-016 Lisboa, Portugal"}]},{"given":"Ana M.","family":"Santos","sequence":"additional","affiliation":[{"name":"cE3c\u2014Centre for Ecology, Evolution and Environmental Changes, CHANGE\u2014Global Change and Sustainability Institute, Faculdade de Ci\u00eancias, Universidade de Lisboa, Edif\u00edcio C2, Piso 5, Sala 2.5.46, Campo Grande, 1749-016 Lisboa, Portugal"},{"name":"Soilvitae Lda., Rua Espir\u00edto Santo, n\u00ba 18, 6060-071 Idanha-A-Nova, Portugal"}]},{"given":"Sanaa","family":"Kamah","sequence":"additional","affiliation":[{"name":"TRICHODEX, S.L.U, Pol\u00edgono Industrial Carretera de la Isla, lote 44-45, 41700 Seville, Spain"}]},{"given":"Silvia","family":"Castillo","sequence":"additional","affiliation":[{"name":"TRICHODEX, S.L.U, Pol\u00edgono Industrial Carretera de la Isla, lote 44-45, 41700 Seville, Spain"}]},{"given":"Khalid","family":"Akdi","sequence":"additional","affiliation":[{"name":"TRICHODEX, S.L.U, Pol\u00edgono Industrial Carretera de la Isla, lote 44-45, 41700 Seville, Spain"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3100-463X","authenticated-orcid":false,"given":"Cristina","family":"Cruz","sequence":"additional","affiliation":[{"name":"cE3c\u2014Centre for Ecology, Evolution and Environmental Changes, CHANGE\u2014Global Change and Sustainability Institute, Faculdade de Ci\u00eancias, Universidade de Lisboa, Edif\u00edcio C2, Piso 5, Sala 2.5.46, Campo Grande, 1749-016 Lisboa, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2026,1,28]]},"reference":[{"key":"ref_1","first-page":"20120410","article-title":"Growing water scarcity in agriculture: Future challenge to global water security","volume":"371","author":"Falkenmark","year":"2013","journal-title":"Philos. Trans. A Math. Phys. Eng. Sci."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"e70332","DOI":"10.1111\/ppl.70332","article-title":"Advancements in Water-Saving Strategies and Crop Adaptation to Drought: A Comprehensive Review","volume":"177","author":"Padilla","year":"2025","journal-title":"Physiol. Plant."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"185","DOI":"10.1051\/agro:2008021","article-title":"Plant drought stress: Effects, mechanisms and management","volume":"29","author":"Farooq","year":"2009","journal-title":"Agron. Sustain. Dev."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"928","DOI":"10.52586\/4998","article-title":"Approaches for the amelioration of adverse effects of drought stress on crop plants","volume":"26","author":"Dubey","year":"2021","journal-title":"Front. Biosci. Landmark"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"R1246","DOI":"10.1016\/j.cub.2023.10.028","article-title":"Enhancing climate change resilience in agricultural crops","volume":"33","author":"Soanes","year":"2023","journal-title":"Curr. Biol."},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Hejazi, M., Da Silva, S., Miralles-Wilhelm, F., Kim, S., Kyle, P., Liu, Y., Vernon, C., Delgado, A., Edmonds, J., and Clarke, L. (2023). Impacts of water scarcity on agricultural production and electricity generation in the Middle East and North Africa. Front. Environ. Sci., 11.","DOI":"10.3389\/fenvs.2023.1082930"},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Futa, B., Gmitrowicz-Iwan, J., Skersiene, A., Slepetiene, A., and Parasotas, I. (2024). Innovative soil management strategies for sustainable agriculture. Sustainability, 16.","DOI":"10.3390\/su16219481"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"180","DOI":"10.3390\/physiologia2040015","article-title":"Drought Stress Tolerance in plants: Interplay of molecular, biochemical and physiological responses in important development stages","volume":"2","author":"Oguz","year":"2022","journal-title":"Physiologia"},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Haghpanah, M., Hashemipetroudi, S., Arzani, A., and Araniti, F. (2024). Drought tolerance in plants: Physiological and molecular responses. Plants, 13.","DOI":"10.3390\/plants13212962"},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Shaffique, S., Hussain, S., Kang, S., Imran, M., Injamum-Ul-Hoque, M., Khan, M., and Lee, I. (2023). Phytohormonal modulation of the drought stress in soybean: Outlook, research progress, and cross-talk. Front. Plant Sci., 14.","DOI":"10.3389\/fpls.2023.1237295"},{"key":"ref_11","first-page":"100032","article-title":"A review on drought stress in plants: Implications, mitigation and the role of plant growth promoting rhizobacteria","volume":"5","author":"Ahluwalia","year":"2021","journal-title":"Resour. Environ. Sustain."},{"key":"ref_12","unstructured":"European Union (2019). EU 2019. Regulation of The European Parliament and of the Council Laying Down Rules on the Making Available on the Market of EU Fertilising Products and Amending Regulations (EC) No 1069\/2009 and (EC) No1107\/2009 and Repealing Regulation (EC) No 2003\/2003."},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Nader, A., Hauka, F., Afify, A., and El-Sawah, A. (2024). Drought-tolerant bacteria and arbuscular mycorrhizal fungi mitigate the detrimental effects of drought stress induced by withholding irrigation at critical growth stages of soybean (Glycine max, L.). Microorganisms, 12.","DOI":"10.3390\/microorganisms12061123"},{"key":"ref_14","first-page":"e02081","article-title":"Rhizosphere competence and applications of plant growth-promoting rhizobacteria in food production\u2014A review","volume":"23","author":"Igiehon","year":"2024","journal-title":"Sci. Afr."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"104550","DOI":"10.1016\/j.apsoil.2022.104550","article-title":"Multiple modes of action are needed to unlock soil phosphorus fractions unavailable for plants: The example of bacteria- and fungi-based biofertilizers","volume":"178","author":"Basilio","year":"2022","journal-title":"Appl. Soil Ecol."},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Backer, R., Rokem, J., Ilangumaran, G., Lamont, J., Praslickova, D., Ricci, E., Subramanian, S., and Smith, D. (2018). Plant Growth-Promoting Rhizobacteria: Context, mechanisms of action, and roadmap to commercialization of biostimulants for sustainable agriculture. Front. Plant Sci., 9.","DOI":"10.3389\/fpls.2018.01473"},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Ait Bessai, S., Cruz, J., Carril, P., Melo, J., Santana, M.M., Mouazen, A.M., Cruz, C., Yadav, A.N., Dias, T., and Nabti, E.-H. (2023). The Plant-Growth Promoting potential of halotolerant bacteria is not phylogenetically determined: Evidence from two Bacillus megaterium strains isolated from saline soils used to grow wheat. Microorganisms, 11.","DOI":"10.3390\/microorganisms11071687"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1574","DOI":"10.1186\/s40064-016-3232-z","article-title":"Crop management as a driving force of plant growth promoting rhizobacteria physiology","volume":"5","author":"Melo","year":"2016","journal-title":"Springerplus"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"13","DOI":"10.1016\/j.micres.2015.12.003","article-title":"Enhancement of drought stress tolerance in crops by plant growth promoting rhizobacteria","volume":"184","author":"Vurukonda","year":"2016","journal-title":"Microbiol. Res."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"100410","DOI":"10.1016\/j.cpb.2024.100410","article-title":"Effect of biostimulants on the chemical profile of food crops under normal and abiotic stress conditions","volume":"40","author":"Boutahiri","year":"2024","journal-title":"Curr. Plant Biol."},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Di Sario, L., Boeri, P., Matus, J., and Pizzio, G. (2025). Plant biostimulants to enhance abiotic stress resilience in crops. Int. J. Mol. Sci., 26.","DOI":"10.3390\/ijms26031129"},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Buss, W., Belt, K., Hein, Z., Putri, A., Zhu, S., Suwandari, H., and Bentley, A. (2025). Hurdles to overcome to achieve biostimulant-driven, low chemical input crop production. Plants People Planet.","DOI":"10.1002\/ppp3.70030"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"122852","DOI":"10.1016\/j.foreco.2025.122852","article-title":"Influence of drought stress on the seed germination and seedling survival of Pinus sylvestris and Larix decidua","volume":"591","author":"Tiebel","year":"2025","journal-title":"For. Ecol. Manag."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"1297","DOI":"10.1111\/plb.13416","article-title":"Drought affects the performance of native oak seedlings more strongly than competition with invasive crested wattle seedlings","volume":"24","author":"Santamarina","year":"2022","journal-title":"Plant Biol."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"177","DOI":"10.1016\/j.apsoil.2017.12.025","article-title":"Arbuscular mycorrhizal fungal species differ in their capacity to overrule the soil\u2019s legacy from maize monocropping","volume":"125","author":"Dias","year":"2018","journal-title":"Appl. Soil Ecol."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"719","DOI":"10.1016\/S0168-9452(01)00460-5","article-title":"Photosynthetic characteristics and protective mechanisms against oxidative stress during chilling and subsequent recovery in two maize varieties differing in chilling sensitivity","volume":"161","author":"Aroca","year":"2001","journal-title":"Plant Sci."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"867","DOI":"10.1093\/oxfordjournals.pcp.a076232","article-title":"Hydrogen-peroxide is scavenged by ascorbate-specific peroxidase in spinach-chloroplasts","volume":"22","author":"Nakano","year":"1981","journal-title":"Plant Cell Physiol."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"17","DOI":"10.1007\/s11240-010-9699-3","article-title":"Biochemical, physiological and growth changes in response to salinity in callus cultures of Sesuvium portulacastrum L","volume":"102","author":"Lokhande","year":"2010","journal-title":"Plant Cell Tissue Organ Cult."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"1559325815588510","DOI":"10.1177\/1559325815588510","article-title":"Dependence of guaiacol peroxidase activity and lipid peroxidation rate in drooping birch (Betula pendula Roth) and tillet (Tilia cordata Mill) leaf on motor traffic pollution intensity","volume":"13","author":"Erofeeva","year":"2015","journal-title":"Dose Response"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"346","DOI":"10.1007\/BF00197534","article-title":"Drought induces oxidative stress in pea plants","volume":"194","author":"Moran","year":"1994","journal-title":"Planta"},{"key":"ref_31","doi-asserted-by":"crossref","unstructured":"Opoku, E., Sahu, P., Findurov\u00e1, H., Holub, P., Urban, O., and Klem, K. (2024). Differential physiological and production responses of C3 and C4 crops to climate factor interactions. Front. Plant Sci., 15.","DOI":"10.3389\/fpls.2024.1345462"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"100802","DOI":"10.1016\/j.stress.2025.100802","article-title":"Can biostimulants enhance plant resilience to heat and water stress in the Mediterranean hotspot?","volume":"16","author":"Carillo","year":"2025","journal-title":"Plant Stress"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"e70450","DOI":"10.1111\/ppl.70450","article-title":"Processing tomato responses to plant-based biostimulants are modulated by environmental conditions","volume":"177","author":"Fusco","year":"2025","journal-title":"Physiol. Plant."},{"key":"ref_34","doi-asserted-by":"crossref","unstructured":"Franzoni, G., Cocetta, G., Prinsi, B., Ferrante, A., and Espen, L. (2022). Biostimulants on crops: Their impact under abiotic stress conditions. Horticulturae, 8.","DOI":"10.3390\/horticulturae8030189"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"104276","DOI":"10.1016\/j.apsoil.2021.104276","article-title":"Meta-analysis of maize responses to Azospirillum brasilense inoculation in Brazil: Benefits and lessons to improve inoculation efficiency","volume":"170","author":"Barbosa","year":"2022","journal-title":"Appi. Soil Ecol."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"109261","DOI":"10.1016\/j.plaphy.2024.109261","article-title":"Unveiling contribution and fate of nitrogen with 15N techniques affected by microbial co-inoculation on field-grown maize: A novel approach to optimize N-fertilizer use efficiency","volume":"217","author":"Galindo","year":"2024","journal-title":"Plant Physiol. Biochem."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"105757","DOI":"10.1016\/j.agwat.2019.105757","article-title":"Improving sweet corn (Zea mays L. var saccharata) growth and yield using Pseudomonas fluorescens inoculation under varied watering regimes","volume":"226","author":"Zarei","year":"2019","journal-title":"Agric. Water Manag."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"109220","DOI":"10.1016\/j.soilbio.2023.109220","article-title":"Benefits in plant N uptake via the mycorrhizal pathway in ample soil moisture persist under severe drought","volume":"187","author":"Bitterlich","year":"2023","journal-title":"Soil Biol. Biochem."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"81","DOI":"10.5433\/1679-0359.2019v40n1p81","article-title":"Can co-inoculation of Rhizobium tropici and Azospirillum brasilense increase common bean nodulation and grain yield?","volume":"40","author":"Steiner","year":"2019","journal-title":"Semin. Cienc. Agrar."},{"key":"ref_40","doi-asserted-by":"crossref","unstructured":"Kuan, K., Othman, R., Rahim, K., and Shamsuddin, Z. (2016). Plant Growth-Promoting Rhizobacteria inoculation to enhance vegetative growth, nitrogen fixation and nitrogen remobilisation of maize under greenhouse conditions. PLoS ONE, 11.","DOI":"10.1371\/journal.pone.0152478"},{"key":"ref_41","doi-asserted-by":"crossref","unstructured":"Nour, M., Aljabi, H., AL-Huqail, A., Horneburg, B., Mohammed, A., and Alotaibi, M. (2024). Drought responses and adaptation in plants differing in life-form. Front. Ecol. Evol., 12.","DOI":"10.3389\/fevo.2024.1452427"},{"key":"ref_42","doi-asserted-by":"crossref","unstructured":"Asif, A., Ali, M., Qadir, M., Karthikeyan, R., Singh, Z., Khangura, R., Di Gioia, F., and Ahmed, Z. (2023). Enhancing crop resilience by harnessing the synergistic effects of biostimulants against abiotic stress. Front. Plant Sci., 14.","DOI":"10.3389\/fpls.2023.1276117"},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"100008","DOI":"10.1016\/j.stress.2021.100008","article-title":"Iron homeostasis in plants and its crosstalk with copper, zinc, and manganese","volume":"1","author":"Rai","year":"2021","journal-title":"Plant Stress"},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"39","DOI":"10.1080\/00380768.2015.1123116","article-title":"Ecophysiology of iron homeostasis in plants","volume":"62","author":"Krohling","year":"2016","journal-title":"Soil Sci. Plant Nutr."},{"key":"ref_45","doi-asserted-by":"crossref","unstructured":"Yan, Y., Guo, C., Glick, B., and Tian, J. (2025). Pseudomonas sp. UW4 enhances drought resistance in garlic by modulating growth and physiological parameters. Horticulturae, 11.","DOI":"10.3390\/horticulturae11101170"},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"117648","DOI":"10.1016\/j.indcrop.2023.117648","article-title":"Canola inoculation with Pseudomonas baetica R27N3 under salt stress condition improved antioxidant defense and increased expression of salt resistance elements","volume":"206","author":"Neshat","year":"2023","journal-title":"Ind. Crops Prod."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"22296","DOI":"10.1021\/acsomega.3c00870","article-title":"Multifaceted impacts of plant-beneficial Pseudomonas spp. in managing various plant diseases and crop yield improvement","volume":"8","author":"Mehmood","year":"2023","journal-title":"ACS Omega"},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"105737","DOI":"10.1016\/j.apsoil.2024.105737","article-title":"The diazotrophic bacteria Azospirillum baldaniorum and A. brasilense improve wheat seedlings\u2019 nitrogen budget through ammonia scavenging","volume":"204","author":"Dias","year":"2024","journal-title":"Appl. Soil Ecol."}],"container-title":["Resources"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2079-9276\/15\/2\/20\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,1,28]],"date-time":"2026-01-28T15:35:31Z","timestamp":1769614531000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2079-9276\/15\/2\/20"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,1,28]]},"references-count":48,"journal-issue":{"issue":"2","published-online":{"date-parts":[[2026,2]]}},"alternative-id":["resources15020020"],"URL":"https:\/\/doi.org\/10.3390\/resources15020020","relation":{},"ISSN":["2079-9276"],"issn-type":[{"value":"2079-9276","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,1,28]]}}}