Original article Biofortification of wheat through inoculation of plant growth promoting rhizobacteria and cyanobacteria Anuj Rana a , Monica Joshi a , Radha Prasanna a , Yashbir Singh Shivay b , Lata Nain a, * a Division of Microbiology, Indian Agricultural Research Institute, New Delhi 110 012, India b Division of Agronomy, Indian Agricultural Research Institute, New Delhi, India article info Article history: Received 3 February 2011 Received in revised form 5 January 2012 Accepted 16 January 2012 Available online 2 February 2012 Handling editor: Kristina Lindström Keywords: Biofortification Malnutrition Micronutrients PGPR Wheat abstract Biofortification is a novel approach which can lead to the development of micronutrient dense staple crops. However, the role of microorganisms in improving the nutritional status of plants has been less investigated. In our study, one bacterial (Providencia sp. PW5) and three cyanobacterial strains CW1, CW2 and CW3 (Anabaena sp., Calothrix sp. and Anabaena sp. respectively) were evaluated in a field experi- ment, for their role in improving the nutritional quality of wheat grains, in terms of protein content and important micronutrients (Fe, Cu, Zn and Mn). An enhancement of 18.6% in protein content was recorded with PW5 þ N 60 P 60 K 60 as compared to fertilizer control (N 60 P 60 K 60 ). Comparative analysis with fertilizer control (N 60 P 60 K 60 ) revealed that inoculation of Providencia sp. PW5 þ N 60 P 60 K 60 recorded statically at par values for Zn accumulation (41.73 mg kg 1 ) and resulted in an increase of 105.3, 36.7 and 150.0% in Fe, Mn and Cu respectively. Our study clearly emphasizes the need for the inclusion of PGPR to complement the existing biofortification strategies for reducing malnutrition in developing countries. Ó 2012 Elsevier Masson SAS. All rights reserved. 1. Introduction Plant growth promoting rhizobacteria (PGPR) include beneficial bacteria that colonize plant roots and enhance plant growth by a wide variety of mechanisms [1]. The use of PGPR is steadily increasing in agriculture, as it offers an attractive way to reduce the use of chemical fertilizers, pesticides and related agrochemicals. Micronutrient malnutrition is known to affect more than half of the world’s population and considered to be among the most serious global challenges to humankind (Copenhagen consensus 2004; http://www.copenhagenconsensus.com). Modern plant breeding has been historically oriented towards achieving high agronomic yields rather than nutritional quality and other efforts related to alleviating this problem have been primarily through industrial fortification or pharmaceutical supplementation. Micro- nutrient malnutrition or the hidden hunger is very common among women and preschool children caused mainly by low dietary intake of micronutrients, especially Zn and Fe [2]. Biofortification has been defined as the process of increasing the bioavailable concentrations of essential elements in edible portions of crop plants through agronomic intervention or genetic selection. The Consultative Group on International Agricultural Research (CGIAR; http://www. cgiar.org) has been investigating the genetic potential to increase bioavailable Fe and Zn in staple food crops such as rice, wheat, maize, common beans and cassava [3], however, information on interventions using PGPR or other biological agents is limited [4]. Secretion of phytosiderophores by microorganisms and plants in restricted spatial and temporal windows represent an efficient strategy for uptake of iron and other micronutrients by plants from the rhizosphere. Analysis of the complex interactions between soils, plants and microbes in relation with micronutrient dynamics represents a unique opportunity to enhance our knowledge of the rhizosphere ecology. Such progress can provide information and tools enabling us to develop strategies to improve plant nutrition and health with decrease in the application of chemical inputs. Microorganisms are known to differ significantly in competing with higher plants for micronutrients [5] and application of FYM (farmyard manure) or other organic manures also play a critical role in the kinetics of mineral uptake in plants [6]. Among bacteria, a lot of attention has been dedicated to the siderophore-mediated iron uptake by fluorescent pseudomonads. A number of other mecha- nisms are also involved in the sequestration and transformation by microorganisms in soil such as production of acids, alkalis etc. PGPR constitute a significant part of the protective flora that benefit plants by enhancing root function, suppressing disease and accel- erating growth and development [1]. Steven [5] pointed out that * Corresponding author. Tel.: þ91 11 25847649; fax: þ91 11 25846420. E-mail address: latarajat@yahoo.co.in (L. Nain). Contents lists available at SciVerse ScienceDirect European Journal of Soil Biology journal homepage: http://www.elsevier.com/locate/ejsobi 1164-5563/$ e see front matter Ó 2012 Elsevier Masson SAS. All rights reserved. doi:10.1016/j.ejsobi.2012.01.005 European Journal of Soil Biology 50 (2012) 118e126