Tailoring Next Generation Plant Growth Promoting Microorganisms as Versatile Tools beyond Soil Desalinization: A Road Map towards Field Application

Abstract

Plant growth promoting bacteria (PGPB) have been the target of intensive research studies toward their efficient use in the field as biofertilizers, biocontrol, and bioremediation agents among numerous other applications. Recent trends in the field of PGPB research led to the development of versatile multifaceted PGPB that can be used in different field conditions such as biocontrol of plant pathogens in metal contaminated soils. Unfortunately, all these research efforts lead to the development of PGPB that failed to perform in salty environments. Therefore, it is urgently needed to address this drawback of these PGPB toward their efficient performance in salinity context. In this paper we provide a review of state-of-the-art research in the field of PGPB and propose a road map for the development of next generation versatile and multifaceted PGPB that can perform in salinity. Beyond soil desalinization, our study paves the way towards the development of PGPB able to provide services in diverse salty environments such as heavy metal contaminated, or pathogen threatened. Smart development of salinity adapted next generation biofertilizers will inevitably allow for mitigation and alleviation of biotic and abiotic threats to plant productivity in salty environments.

Exploitation of Plant Growth Promoting Bacteria for Sustainable Agriculture: Hierarchical Approach to Link Laboratory and Field Experiments

“…However, this approach is limited since it does not take into account that in real conditions the PGPB efficiency depends not only on the individual traits analysed but also on their interaction with other factors, which can be associated with both plants and the environment. Therefore, to identify efficient PGPB, it is essential to evaluate as many variables as possible in greenhouse experiments, in order to simulate the real field conditions [ 66 , 67 , 68 , 69 ]. Moreover, considering that the environmental conditions have strong influence on the microbial communities associated with plants, having information about the place of origin of the tested strains can be helpful for field application [ 67 , 68 ].…”

The Contrivance of Plant Growth Promoting Microbes to Mitigate Climate Change Impact in Agriculture

“…Excessive ROS accumulation in plant cells leads to numerous changes and damages, which in turn affect the condition of the plant, its yield and survival [83]. This could affect DNA, chlorophyll, enzymes and other proteins, which may lead to detrimental effects, and finally even cell death [20,[84][85][86]. To mitigate damage under this stress, plants have created complex antioxidative defense systems, in which involved are antioxidative enzymes and other non-enzymatic antioxidant mechanisms [6].…”

“…Reducing the impact of plant diseases caused by pathogens, mitigating abiotic stress or inducing systemic resistance in competition for nutrients and niches are categorised as indirect mechanisms [6,83]. The most common and successful PGPB belong mainly to the genera Agrobacterium, Azospirillum, Azotobacter, Bacillus, Burkholderia, Pseudomonas, Streptomyces and Serratia [52,84].…”

“…This unusual relation makes AST-PGB an efficient tool for promoting plant growth under abiotic stress conditions [18,135]. It has been reported that some AST-PGPB are even more active under harsh environmental conditions [52,84]. Nagaraju et al demonstrated that the solubilization of zinc compounds decreases significantly with increasing salinity [139].…”

Plant Growth-Promoting Rhizobacteria as a Green Alternative for Sustainable Agriculture

“…Abiotic stresses also hinder soil microbial diversity and physicochemical properties of soil, resulting in lower productivity and yield loss [6]. To counteract the negative impacts of stress on crop plants, the agricultural policy is accentuating sustainable production systems with an emphasis on the use of beneficial soil microorganisms present in the rhizospheric region with multifaceted traits which promote plant growth and play a significant role in battling abiotic stress [7][8][9]. Rhizosphere, the layer of soil encasing the plant root, plays an important role in plant growth and development.…”