Action Mechanisms of Plant Growth Promoting Cyanobacteria in Crops In Situ: A Systematic Review of Literature

Abstract

Background and Aims. An excessive and prolonged use of fertilizers undermines soils’ quality and, consequently, that of the crops they support, thus reducing the content of organic matter and generating environmental damages and problems to human health. Therefore, the use of biofertilizers such as cyanobacteria becomes a promising alternative. However, it is not always possible to generalize these fertilizers’ applicability, because microorganisms may be impacted by the physical and chemical variations of their environment. We will describe the action mechanisms or the characteristics of cyanobacteria involved in plant growth promotion for different crops in situ through a systematic review of scientific literature. Methods. A comprehensive search for original articles in two different databases, ScienceDirect and Scopus, was performed. We included in our search documents published from 2009 to 2018. After the screening process and the addition of gray literature publications, we obtained 23 articles for theoretical analysis. Results. The studies were distributed mainly in Asia and part of Africa, without any important temporal variation. They also showed a tendency to describe the use of cyanobacteria genera such as Anabaena sp., Nostoc sp., and Calothrix sp., besides mechanisms as N2 fixation, phosphate solubilization, phytohormone production, bioactive compounds excretion, and symbiotic associations, mainly on rice, wheat and corn crops. Conclusions. Cyanobacteria fertilizers used in situ are a widespread strategy, mainly in cereal crops. Their use is predominant in countries where cereal crops make an important contribution to their national economy. The great variety of mechanisms and characteristics of cyanobacteria used to promote plant growth in the field demonstrate the dramatic influence that physical, chemical, and biological variables have in their development.

Fertilising Maize with Bio-Based Mineral Fertilisers Gives Similar Growth to Conventional Fertilisers and Does Not Alter Soil Microbiome

“…Similarly, a cluster comprising Acidovorax, Phormidium, and Phormidesmis was specifically associated with the PA treatment. Acidovorax is known to harbour both PGPR and plant pathogenic species [64,65]; Phormidium and Phormidesmis are ubiquitous cyanobacteria found in various environments and sometimes used for plant growth promotion or soil remediation [66][67][68]. Additionally, we observed other beneficial microorganisms associated with specific treatments; e.g., Novihervaspirillum, a common soil genus, was present in the PKA, PD, and C+ treatments [69,70]; Olivibacter, frequently encountered in rhizosphere soil exhibiting PGPR traits [71,72], displayed elevated relative abundance in the PKA, PD, and C+ treatments; Bdellovibrio, a bacterial predator known to house PGPR and biocontrol species [73,74], was detected in the ST and C+ treatments and in lower proportions in PD; and Kocuria, recognised as a PGPR [75], was observed in the ST, PD, and C+ treatments.…”

Harnessing the Synergy of the Cyanobacteria-Plant Growth Promoting Bacteria for Improved Maize (Zea mays) Growth and Soil Health

“…Z. mays requires a significant amount of nitrogen fertilizer, making it important to explore alternative fertilizer sources that offer benefits in agronomy, environmental sustainability, and economics [56,57]. Utilizing cyanobacteria and PGPB could serve as a viable alternative to enhance crop growth and yield in significant crops such as Z. mays, as these microorganisms have the capability to stimulate root system growth [58], nutrient use efficiency (NUE) [59,60], and enhance the uptake of essential nutrients, including nitrogen (N) [38,61].…”

Cyanobacteria: A Futuristic Effective Tool in Sustainable Agriculture

“…Therefore, the symbiotic cyanobacteria are mostly heterocyst-forming strains. They are virtually entirely associated with the genera Nostoc and Anabaena [ 15 ]. Cyanobacteria provide plants with about 88% of the fixed nitrogen in the form of NH 3 and keep only 12% for themselves [ 16 ].…”