Biosafety of Novel Bioinoculants

Abstract

With rapid advances in microbial discovery and inoculant technology, the realm of microbial inoculants has seen a significant shift from the conventional range of microbes viz., Rhizobium, Azospirillum, Azotobacter, etc. to include a wide range of bacterial and fungal genera that colonize the rhizosphere and promote plant growth in a myriad fashion. Such microbial strains with beneficial traits have been included under the umbrella terminologies of Plant Growth Promoting Rhizobacteria (PGPR) and Plant Growth Promoting Rhizofungi (PGRF). While this is definitely a welcome step, it brings along with it a host of pertinent questions, of which the biosafety of the microbial strains used for inoculant formulation is of paramount importance. This rationalization becomes imperative in the present scenario, where the etiology and pathogenesis of several hitherto unknown or lesser known bacterial species are being deciphered, and opportunistic pathogenic properties are being attributed to several commonly occurring environmental microbes. Another issue that needs to be factored in this paradigm is the possible horizontal gene transfer between naturally occurring microbes and the introduced inoculant strains. This assumes significance since horizontal gene transfer amongst organisms plays a larger role in the context of environmental protection and evolving antibiotic resistance. Hence a judicious analysis of the benefits and risks associated with novel microbial inoculants need to be addressed, before its eventual usage. Therefore it is imperative for microbiologist's agronomists and plant protection scientists to be aware about the latest trends in biosafety, in order to make informed decisions in their day to day work. Hence this article will primarily focus on the need for ensuring the biosafety of the newer bioinoculants, and the relevant regulatory frameworks that are in place internationally.

Novel plant growth promoting rhizobacteria—Prospects and potential

“…This rationalization becomes imperative in the present scenario, where the etiology and pathogenesis of several hitherto unknown or lesser known bacterial species are being deciphered, and opportunistic pathogenic properties are being attributed to several commonly occurring environmental microbes. Hence a judicious analysis of the benefits and risks associated with novel microbial inoculants need to be addressed, before its eventual usage (Selvakumar et al, 2014).…”

Engineering root microbiomes for healthier crops and soils using beneficial, environmentally safe bacteria

“…Before the use of bioinoculants can expand further into routine field applications, concrete regulation and testing with a system of assessment of the biosafety of PGPB strains with respect to humans, animals, other plant life, and the environment is needed (Berg 2009;Selvakumar et al 2014). As mentioned earlier, thorough strain characterization is essential along with tests for pathogenicity and toxicity to eliminate strains that pose even a minimal risk.…”

Development of formulations for the application of biofertilizers based on autochthonous microorganisms for high addedvalue crops = Desarrollo de formulaciones para la aplicación de biofertilizantes basados en microorganismos autóctonos para productos agroalimentarios con alto valor añadido

“…Last but not least, biosafety for the environment and humans is an essential issue (Selvakumar et al, 2014). Microorganisms applied in sustainable agriculture should guarantee the protection and the sustainability of agrisystems; thus, it is necessary to ensure that they do not have harmful effects.…”

“…Although the classification of risk in microbial agents may be based of different factors such as the pathogenicity of the organism, modes of transmission, or the microorganism's host range (Selvakumar et al, 2014), there is a guide provided by the World Health Organization (WHO) that proposes classification with four risk groups of infectious organisms. This system indicates the security measures to be carried out according to the risk group to which a microorganism belongs (WHO, 2004).…”