Influence of cyanobacterial inoculation on the culturable microbiome and growth of rice

Abstract

Rice plants are selective with their associations with bacteria that are beneficial for growth, nutrient uptake, exhibit induced resistance or antagonism towards pathogens. Cyanobacteria as bioinoculants are known to promote the growth and health of rice plants. The present investigation was aimed at understanding whether and how cyanobacterial (Calothrix elenkinii) inoculation influenced the rice plant growth and the culturable bacterial populations and identifying the dominant culturable "microbiome" members. The plant tissue extracts were used to enumerate populations of the culturable microbiome members using selected enrichment media with different nutrient levels. About 10-fold increases in population densities of culturable microbiome members in different media were recorded, with some isolates having metabolic potential for nitrogen fixation and phosphorus solubilization. Fatty acid methyl ester (FAME) analysis and 16S rRNA sequencing of selected microbial morphotypes suggested the predominance of the members of Bacillaceae. Significant increases in plant growth attributes, nitrogenase activity and indole acetic acid production, and activities of hydrolytic and defense enzymes were recorded in the Calothrix inoculated plants. The PCR-based analysis and scanning electron microscopic (SEM) observations confirmed the presence of inoculated cyanobacterium inside the plant tissues. This investigation illustrated that cyanobacterial inoculation can play significant roles in improving growth and metabolism of rice directly and interact with the beneficial members from the endophytic microbiome of rice seedlings synergistically.

Soil Algae of El-Farafra Oasis (The Western Desert, Egypt), and N2-fixation Efficiency of Five Heterocytous Cyanophytes

“…Therefore, they could be widely-used as excellent natural bio-fertilizers and in reclamation of the nutrients-poor desert soils of El-Farafra Oasis. In agreement with these results, recent contribution of Priya et al (2015) showed that there is a significant increase in rice plant growth inoculated with Calothrix elenkinii. Goyal (1993) confirmed that Scytonema grows well on the soil surface and fixes more nitrogen than the most Egypt.…”

Effect of Salinity Stress and Microbial Inoculations on Glomalin Production and Plant Growth Parameters of Snap Bean (Phaseolus vulgaris)

“…This is because Rhizobium fixes atmospheric N [49,63] in root nodules (active root nodules were found in most plants treated with Rhizobium), which compensated for a portion of the chlorophyll degradation from salt stress. Microbial inoculations are also reported to increase the chlorophyll content of plant leaves [64,65].…”

Agricultural Microbiology Research Progress in India in the New Millennium

“…Two strains of Gluconacetobacter diazotrophicus isolated from endorhizosphere of sweet sorghum (Acd1 and Acd2) were tested for their plant growth potential and nitrogen-fixing ability along with a reference strain obtained from Brazil (Pal3) under green house and field conditions with sweet sorghum cultivar PC 121 in the presence of fertilizer nitrogen (20 and 40 kg N ha -1 ) applied in the form of isotopically labelled ammonium sulphate [( 15 (NH 4 ) 2 SO 4 ] (Sahai et al, 2015). Priya et al (2015) studied the influence of cyanobacterial inoculation on the culturable microbiome and growth of rice. Many reports on the inoculation of PGPR along with Rhizobium were published (Tsigie et al, 2011).…”