Plant Growth-Prompting Bacteria Influenced Metabolites of &amp;lt;i&amp;gt; Zea mays var. amylacea &amp;lt;/i&amp;gt; and &amp;lt;i&amp;gt;Pennisetum americanum p. &amp;lt;/i&amp;gt; in a Species-Specific Manner

Faten Dhawi,Anna Hess

doi:10.4236/abc.2017.75011

Abstract

Poor soil is one of the agricultural world’s principal challenges, inciting the use of chemical fertilizer’s to improve overall soil quality. However, the use of chemical fertilizer has significant and cascading environmental consequences. Therefore, the use of beneficial microbes’ inoculation in treating poor soil is a considerably ecofriendly sustainable solution. In the current study, we supplemented nutrient-deprived soil with plant growth promoting bacteria (PGPB), Pseudomonas fluorescens. The bacterial inoculations of Pseudomonas fluorescenswere added to the poor soil following two days post-sowing of Zea mays var. amylacea and Pennisetumamericanum p. seedlings. Metabolite analyses were conducted two months after treatment for both shoots and roots using nuclear magnetic resonance method (NMR). The data indicated significant changes in 19 metabolites relative to control in both plants shoot and roots. Among these metabolites, 7 were upregulated in roots of Zea mays var. amylacea, and 9 metabolites were upregulated in roots of Pennisetum americanum p. The PGPB enhanced sugars (fructose, glucose, sucrose) and amino acids (glutamate, alanine and succinate) in roots, while down regulating in shoots of Pennisetum americanum p. The Pseudomonas fluorescens induced, predominantly,Aminoacyl-tRNA related metabolite, and Alanine, aspartate and glutamate metabolite biosynthesis in Zea mays var. amylacea), whereas PGPB induced metabolites in Pennisetum americanum p., dominated by up regulated carbohydrate related (starch and sucrose) metabolites. The difference in some metabolic response between the two plants indicated that PGPB influence has a species-specific manner.

Highlights

Industrialization and the associated consequences of global warming have influenced many aspects of our lives, including agricultural practices and plant production
Plant growth promoting bacteria (B group)was inoculated with 120 ml of Pseudomonas fluorescens suspended in 0.85% NaCl (120 ml/10−8), according to a method described by Dhawi et al, [1]
Metabolite analyses identified 19 compounds that were affected relative to the control (Acetate, Alanine, Choline, Citrate, Formate, Fructose, Gallate, Gluconate, Glucose, Glutamate, Glutamine, Isoleucine, Malate, Succinate, Sucrose, Threonine, Tyrosine, Valine and Trans-Aconitate) in both plants (Zea mays var. amylacea and Pennisetum americanum p.) shoots and roots (Figure 1 and Figure 2(a), Figure 2(b))

Summary

Introduction

Industrialization and the associated consequences of global warming have influenced many aspects of our lives, including agricultural practices and plant production. Soil infertility is one of the most significant outcomes of global warming, due to the increased use of chemical fertilizations which are costly and harmful to environmental systems. There were many studies reporting microorganisms’ ability to increase overall soil quality, including soil fertility [1] [2] and associated plant productivity, disease resistance and stress adaptation [3] [4] [5]. Plant Growth Promoting Bacteria (PGPB) have been found to increase protein expression [6], metabolites and subsequent root growth in several plants [1] [2] [7] resistance to biotic and abiotic stress [8], enriching poor nutrient soil [7]. The PGPB such as Bacillus altitudinis and Pseudomonas putida UW4 increase plant growth and subsequent biomass via producing Indole Acetic Acid (IAA) in the rhizosphere area [9] [10]. Pseudomonas sp. increased plant copper tolerance [11]

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