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International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru 502 324, Telangana, India.
This study highlights the potential of 26 different strains of beneficial microorganisms, including 19 Streptomyces sp. (CAI-13, CAI-17, CAI-21, CAI-24, CAI-26, CAI-68, CAI-78, CAI-85, CAI93, CAI-121, CAI-127, CAI-140, CAI-155, KAI-26, KAI-
27, KAI-32, KAI-90, KAI-180 and MMA-32) and 7 system of rice intensification (SRI) bacterial isolates (SRI-156, SRI-158, SRI-178, SRI-211, SRI-229, SRI-305, and SRI-360), in enhancing the nutrient content of chickpea grains. These beneficial microorganisms have been found to be effective in various crops such as chickpea, pigeonpea, sorghum, rice, pearl millet, tomato, and chili. The field experiment was conducted to evaluate the impact of these plant growth-promoting actinobacteria on seed nutrition in chickpea. The results showed that inoculating the seeds with these microorganisms significantly improved the nutritional values of the chickpea seeds compared to the un-inoculated control. All the Streptomyces sp. were found to enhance the crude protein (up to 12.4%), crude fiber (up to 46.3%), crude fat (up to 33.3%), and total ash (up to 25%) contents of the seeds over the uninoculated control seeds. The bacterial strains also improved the crude protein (up to 13.8%), crude fiber (up to 49.4%), crude fat (up to 19.3%), and total ash (up to 14.3%). Hence, it is concluded that beneficial microbes can serve as a complementary sustainable tool for the existing biofortification strategies.
KEYWORDS: Plant growth-promoting actinobacteria, System of rice intensification (SRI), Streptomyces sp. Chickpea, Biofortification Minerals.
Malnutrition is a persisting global calamity that is prevalent mainly in Africa and South Asia. It exists in three aspects: undernutrition (stunting, wasting, and underweight), obesity, and malnutrition associated with micronutrient deficiency (hidden hunger). The World Health Organization (WHO) estimates over 2 billion people suffer from hidden hunger (Ritchie and Roser, 2017). At the same time, 150.8 million, 50.5 million, and 38.3 million children aged below 5 years are stunted, wasted, and overweight, respectively (Ritchie and Roser, 2017; Global Nutrition Report, 2018). South Asian women and school children are highly vulnerable to malnutrition. One-third of women of reproductive age are anemic and show higher susceptibility to obesity than men (Global Nutrition Report, 2018). Plant breeding and agronomical practices introduced in the 1960s during the green revolution primarily combatted global hunger, especially through large-scale cereal production, providing the necessary calories or proteins to these vulnerable populations (Thavarajah et al., 2014; Roorkiwal et al., 2021). Therefore, biofortification through PGPR (plant growth promoting rhizobacteria) is a sustainable alternative to combat this hidden hunger or micronutrient malnutrition. The utilization of PGPR for biofortification not just encourages us to manage the issue of malnutrition among the population, in addition, improves crop yield, soil fertility, and biodiversity. Biofortification through rhizobacteria has gained popularity to improve Zn and other micronutrient contents in grain crops. For instance, Gopalakrishnan et al. 2016c, Satya et al. 2016, Srinivas et al., 2021 revealed the species from the genera Streptomyces, Pseudomonas, Brevibacterium, Bacillus, Enterobacter, and Acinetobacter as potential candidates for biofortification and biocontrol in plants. These microorganisms also can incorporate micronutrients inside eatable plant tissues through solubilization of their indigenous insoluble sources present in the soil.
Actinomycetes, particularly those belonging to the genus Streptomyces, can induce antioxidant enzymes in chickpea leaves, potentially leading to improved nutrient content in the grains. In recent years, researchers have explored the potential of actinomycetes to enhance the nutritional value of various crops, including chickpeas. Therefore, in the present study 26 bacterial strains including actinomycetes which are previously reported as plant growth promoting bacteria and as natural pest control agents from ICRISAT were tested for their nutritional improvement in chickpea grains by seed inoculation in a field study.
This study investigates 26 different strains of PGP (plant growth-promoting) bacteria, found in herbal vermicompost and SRI (System of Rice Intensification) rice rhizosphere soils. Among these strains, 19 are Streptomyces species and 7 are SRI-bacterial isolates. These bacteria have been reported as PGP and biocontrol agents in various crops like chickpea, pigeonpea, sorghum, rice, pearl millet, tomato, and chilli (Gopalakrishnan et al., 2011a; 2011b; 2011c; 2012a; 2012b; 2013a; 2013b; 2014; 2015a, 2015b; 2015 c;
2016a, 2016b, 2016c, 2016d; 2020a; 2021; Sathya et al. 2016; Sravani et al., 2021, Srinivas et al., 2020; 2023; Sambangi et al., 2022). The genome sequences of 16 Streptomyces strains, which demonstrate potential for plant growth promotion (PGP) activities in numerous crops, have been successfully decoded. (Gopalakrishnan et al., 2020b).
The field experiment was carried during the post- rainy cropping season at ICRISAT (17°30ꞌ N; 78°16ꞌ E; altitude 549 m), Patancheru, India. The experimental site featured Vertisol soil, which is rich in clay content (52%), silt (21%), and sand (26%). The soil had an alkaline pH of 7.7-8.5 and an organic carbon content of 0.4-0.6%. The soil depth was at least 1.2 meters, and it could retain around 200 mm of plant-available water in a 120-cm soil profile. The top 15 cm of the rhizosphere soil contained 24.7 mg kg-1 of available nitrogen, 8.6 mg kg-1 of available phosphorus, and 298 mg kg-1 of available potassium. The field was kept fallow except for the post- rainy season crop. The land was prepared into broad beds and furrows, with beds measuring 1.2 meters wide and flanked by 0.3-meter furrows in both seasons. Fertilizers, including 18 kg N ha-1 and 20 kg P ha-1 as di-ammonium phosphate, were applied and incorporated into the soil. The experiment was conducted using a randomized complete block design (RCBD) with three replicates and plot sizes of 4 meters by 3 ridges (rows).
The 26 selected bacterial strains were cultured individually on Strach casein broth for Streptomyces sp., and Luria Bertani broth of SRI- bacterial strains. The chickpea seeds (ICCV 2) were treated with bacterial strains at a concentration of 108 CFU/ml for 40 minutes, then sown immediately by hand planting. The plants were sown in rows 30 cm apart with a depth of 5 cm, aiming for at least 26 plants per square meter. Throughout the growth period, until the flowering stage, the plants were inoculated with the respective bacterial strains every 15 days by applying them to the soil near the plants. In control plot were maintained without bacterial treatment. During the cultivation, no pesticides were used as no significant diseases or pests were observed. The crop was manually harvested. After crop maturity seeds were collected treatment wise, dried, grounded and then flour was stored in paper bags. The samples were properly labelled and sent to TNAU (Tamil Nadu Agricultural University) for analyzing crude protein (Kjeldahl method), crude fat (Soxhlet extraction method), crude fiber (AOAC method, 2005) and total ash.
Among the 26 different strains of bacteria, all the Streptomyces sp. enhanced the crude protein (4% to 12.4%), crude fiber (4.4% to 46.3%), crude fat (2.7% to 33.3%), and total ash (14.3% to 25%) of chickpea seeds, same as all SRI-bacterial isolates have significantly improved the crude protein (0.3% to 13.8%), crude fiber (28.3% to 49.4%), crude fat (0.7% to 19.3%), and total ash (up to 14.3%) over the seeds of control plants (Table 1). The Streptomyces sp. and bacteria sp. used in this experiment were earlier reported to enhance the plant growth promotion in chickpea crop (Gopalakrishnan et al., 2011a; 2011b; 2011c; 2012a; 2012b; 2013a; 2013b; 2014; 2015a, 2015b; 2015 c; 2016a, 2016b, 2016c,
2016d; 2020a; 2021; Sathya et al. 2016; Sravani et al., 2021, Srinivas et al., 2020; 2023; Sambangi et al., 2022).
The results of present investigation were similar to the results of Gopalakrishnan et al. (2022) in which consortium of Streptomyces sp. have significantly improved the crude protein, crude fiber, crude fat and total ash content of chickpea grains. Also, the results are parallel with Srinivas et al., 2021 wherein the Streptomyces strains have significantly increased the grain nutrient contents of pearl millet hybrids and showed a PGP based sustainable biofortification. The results are in line with Sathya et al., 2016, where they evaluated the plant growth promoting actinobacterial cultures increased the seed mineral density of chickpea significantly. Gopalakrishnan et al. (2016) assessed bacterial cultures for their plant growth promotion and biofortification where they significantly improved the mineral content of grains in chickpea and pigeon pea crops. Therefore, it suggests that microbial based biofortification of seeds is a sustainable tool for existing biofortification strategies.
In this study, we examined the potential of 26 different strains of microorganisms, including 19 Streptomyces sp. and 7 SRI-bacterial isolates, to
enhance the nutrient content of chickpea grains. The field experiment was conducted during the post-rainy cropping season at ICRISAT, Patancheru, India, to evaluate the impact of these plant growth-promoting actinobacteria on seed nutrition in chickpea. The results showed that inoculating the seeds with these microorganisms significantly improved the nutritional values of the chickpea seeds compared to the un- inoculated control. The Streptomyces sp. and bacterial isolates improved various nutritional parameters, such as crude protein, crude fiber, crude fat, and total ash content in chickpea grains. These findings suggest that microbial inoculum might be a complementary sustainable method for current nutritional approaches, potentially decreasing the utilization of chemical fertilizers in agricultural fields. The use of microbial-based biofortification of seeds can be considered a sustainable tool for existing biofortification strategies, contributing to combating malnutrition and improving crop yield, soil fertility, and biodiversity.
This work has been undertaken as part of the CGIAR Research Program on Grain Legumes Dry Land Cereals.
AOAC 2005. Official Methods of Analysis of Association of Official Analytical Chemists. 18th Edition, Washington, DC.
Global Nutrition Report. (2018). https:// globalnutritionreport.org/reports/global nutrition- report-2018 /executive-summary.
Gopalakrishnan, S., Kiran, B.K., Humayun, P., Vidya, M.S., Deepthi, K and Rupela, O. 2011a. Biocontrol of charcoal-rot of sorghum by actinomycetes isolated from herbal vermicompost. African Journal of Biotechnology. 10(79): 18142-18152.
Gopalakrishnan, S., Humayun, P., Kiran, B.K., Kannan, I.G., Vidya, M.S., Deepthi, K and Rupela O. 2011b. Evaluation of bacteria isolated from rice rhizosphere for biological control of charcoal rot of sorghum caused by Macrophomina phaseolina (Tassi) Goid. World Journal of Microbiol Biotechnol. 27(6): 1313-21.
Gopalakrishnan, S., Pande, S., Sharma, M., Humayun, P., Kiran, B.K., Sandeep, D., Sree Vidya, M., Deepthi, K and Rupela, Om. 2011c. Evaluation of actinomycete isolates obtained from herbal vermicompost for the biological control of Fusarium wilt of chickpea. Crop Protection. 30(8).
Gopalakrishnan, S., Humayun, P., Srinivas, S., Vijayabharathi, R., Ratnakumari, B and Rupela O. 2012a. Plant growth-promoting traits of biocontrol potential Streptomyces isolated from herbal vermicompost. Biocontrol Science & Technology. 22(10): 1199-1210.
Gopalakrishnan, S., Upadhyaya, H., Vadlamudi, S., Humayun, P., Vidya, M.S., Alekhya, G., Singh, A., Vijayabharathi, R., Bhimineni, R.K., Seema, M., Rathore, A and Rupela, O. 2012b. Plant growth- promoting traits of biocontrol potential bacteria isolated from rice rhizosphere. Springerplus. 1(1): 71.
Gopalakrishnan, S., Srinivas, V., Shravya, A., Prakash, B., Ratnakumari, B., Vijayabharathi, R and Rupela, 2013a. Evaluation of Streptomyces spp. for their Plant growth-promoting traits in rice. Canadian Journal of Microbiology. 59: 534-539.
Gopalakrishnan, S., Srinivas, V., Sree Vidya, M and Rathore, A. 2013b. Plant growth-promoting activities of Streptomyces spp. in sorghum and rice. Springerplus. 2: 574.
Gopalakrishnan, S., Srinivas, V., Prakash, B., Arumugam, S., Vijayabharathi, R., Rupela, O., Kudapa, H., Krishnamohan, K and Varshney, R.K. 2014. Evaluation of Streptomyces strains isolated from herbal vermicompost for their plant growth- promotion traits in rice. Microbiological Research. 169: 40-48.
Gopalakrishnan, S., Srinivas, V., Alekhya, G., Prakash, B., Kudapa, H., Rathore, A and Varshney, R.K. 2015a. The extent of grain yield and plant growth enhancement by plant growth-promoting broad-spectrum Streptomyces sp. in chickpea. SpringerPlus. 4(31): 1-10.
Gopalakrishnan, S., Srinivas, V., Alekhya, G., Prakash, B., Kudapa, H and Varshney, R.K. 2015b. Evaluation of Broad-Spectrum Streptomyces sp. for Plant Growth Promotion Traits in Chickpea (Cicer arietinum L.). Philippine Agriculture Scientist. 98(3): 270-278.
Gopalakrishnan, S., Srinivas, V., Alekhya, G and Prakash, B. 2015c. Effect of plant growth-promoting Streptomyces sp. on growth promotion and grain yield in chickpea (Cicer arietinum L). 3 Biotech. 5: 799-806.
Gopalakrishnan, S., Sathya, A and Vijayabharathi, R. 2016a. A book entitled “Plant Growth-Promoting Actinobacteria: A New Avenue for Enhancing the Productivity & Soil Fertility of Grain Legumes” published by Springer Singapore ISBN 978-981- 10-0705-7.
Gopalakrishnan, S., Srinivas, V and Sameer Kumar, C.V. 2016b. Plant growth-promotion traits of Streptomyces sp. in pigeonpea. Legume Perspectives. 11: 43-44.
Gopalakrishnan, S., Vadlamudi S., Samineni, S and Sameer Kumar, C.V. 2016c. Plant growth- promotion and biofortification of chickpea and pigeonpea through inoculation of biocontrol potential bacteria, isolated from organic soils. Springerplus. 5(1):1882.
Gopalakrishnan, S., Rajendran, V., Arumugam, S., Sharma, H.C., Vadlamudi, S., Bhimineni, R.K., V Gonzalez, S., M Melø, T, and Simic, N. 2016d. Insecticidal activity of a novel fatty acid amide derivative from Streptomyces species against Helicoverpa armigera. Nat Prod Res. 30(24): 2760- 2769.
Gopalakrishnan, S., Sharma, R., Srinivas, V., Naresh, N., Mishra, S.P., Ankati, S., Pratyusha, S., Govindaraj, M., Gonzalez, S.V., Nervik, S and Simic, N. 2020a. Identification and characterization of a Streptomyces albus strain and its secondary metabolite organophosphate against charcoal rot of sorghum. Plants. 9: 1727.
Gopalakrishnan, S., Thakur, V., Saxena, R.K., Vadlamudi, S., Purohit, S., Kumar, V., Rathore, A., Chitikineni, A and Varshney, R.K. 2020b. Complete genome sequence of sixteen plant growth promoting Streptomyces strains. Scientific Reports. 10(1): 10294.
Gopalakrishnan, S., Srinivas, V., Naresh, N., Mishra, S.P., Ankati, S., Pratyusha, S., Madhuprakash, J., Govindaraj, M and Sharma, R. 2021. Deciphering the antagonistic effect of Streptomyces spp. and host-plant resistance induction against charcoal rot of sorghum. Planta. 253: 57.
Gopalakrishnan, S., Srinivas, V., Chand, U., Pratyusha, S and Samineni, S. 2022. Streptomyces consortia- mediated plant growth-promotion and yield performance in chickpea. 3 Biotech. 12(11): 318.
Ritchie, H., and Roser, M. 2017. Micronutrient Deficiency. Our World in Data. https://ourworldindata.org/ micronutrient-deficiency. (Accessed April 21, 2021).
Roorkiwal, M., Pandey, S., Thavarajah, D., Hemalatha, R. and Varshney, R.K., 2021. Molecular mechanisms and biochemical pathways for micronutrient acquisition and storage in legumes to support biofortification for nutritional security. Frontiers in Plant Science. 12. 682842.
Sathya, A., Vijayabharathi, R., Srinivas, V and Gopalakrishnan, S. 2016. Plant growth-promoting actinobacteria on chickpea seed mineral density: an upcoming complementary tool for sustainable biofortification strategy. 3 Biotech. 6: 138.
Sambangi, P. and Gopalakrishnan, S. 2022. Streptomyces-mediated synthesis of silver nanoparticles for enhanced growth, yield, and grain nutrients in chickpea. Biocatalysis and Agricultural Biotechnology. 47. 102567.
Sravani, A., Vadlamudi, S., Sambangi, P. and Gopalakrishnan, S. 2021. Streptomyces consortia- mediated plant defense against Fusarium wilt and plant growth-promotion in chickpea. Microb Pathogenesis 157: 104961.
Srinivas, V., Gopalakrishnan, S., Kamidi, J.P and Chander, G. 2020. Effect of plant growth-promoting Streptomyces sp. on plant growth and yield of tomato and chilli. Andhra Pradesh Journal of Agricultural Science. 6(2): 65-70.
Srinivas, V., Naresh, Pratyusha, S., Ankati, S., Govindaraj, M. and Gopalakrishnan, S. 2022. Enhancing pearl millet hybrids performance for yield and nutrients through plant growth-promoting Streptomyces spp.: An agronomic biofortification approach. Crop & Pasture Sci 73(5): 484-493.
Srinivas, V., Pratyusha, S. and Gopalakrishnan, S. 2023. Bio-formulations for plant growth-promoting Streptomyces sp. Andhra Pradesh Journal of Agricultural Sciences. 9(4): 279-285.
Thavarajah, D., Thavarajah, P. and Gupta, D.S., 2014. Pulses biofortification in genomic era: multidisciplinary opportunities and challenges. Legumes in the Omic Era. 207-220. (New York: Springer). 207-220.