The Diversity of Culture-Dependent Gram-Negative Rhizobacteria Associated with Manihot esculenta Crantz Plants Subjected to Water-Deficit Stress

Abstract

There is a lack of studies on the root-associated bacterial microbiome of cassava plants. The identification and characterization of rhizobacteria can contribute to understanding the adaptation of the agriculturally important crop plants to abiotic stress. Rhizobacteria play a significant role in plants, as they can alleviate the drought stress by various mechanisms that enhance the plant growth under these stressor conditions. In this study, Gram-negative bacterial strains from the plant rhizosphere of cassava Manihot esculenta Crantz CIAT MCOL1734 variety subjected to water deprivation were isolated, characterized according to their morphological properties, and then identified by VITEK® 2. An increase in the diversity, abundance, and species richness of Gram-negative rhizobacterial community was found in cassava plants subjected to water-deficit stress. In total, 58 rhizobacterial strains were isolated from cassava plants. The identification process found that the bacteria belonged to 12 genera: Achromobacter, Acinetobacter, Aeromonas, Buttiauxella, Cronobacter, Klebsiella, Ochrobactrum, Pluralibacter, Pseudomonas, Rhizobium, Serratia, and Sphingomonas. Interestingly, Pseudomonas luteola and Ocrhobactrum anthropi were rhizobacteria isolated exclusively from plants submitted to drought conditions. The cassava roots constitute a great reservoir of Gram-negative bacteria with a remarkable potential for biotechnological application to improve the drought tolerance of plant crops under water-deficit conditions.

The Impact of Drought Stress on Soil Microbial Community, Enzyme Activities and Plants

“…Drought is defined as a state of the total water capacity being within the range of 12-20% for a period of 16 days and can be distinguished from the water deficit, which is the state of water capacity falling below 30% [14][15][16][17].…”

PGPR Preparation Training to Improve Cassava Production for KOPASAMU Farmers in Kalasan

“…The goal is to be able to produce PGPR commercially in the future. For this reason, business management and quality testing are needed [11,12,13].…”

“…Research results from Ilyas (2020) showed that giving mycorrhizal inoculums to Renek's cassava plants can increase the tuber yield of cassava by 5.18 tons/ha compared to Renek's cassava plants that are not given mycorrhizal inoculums of 1.68 tons/ha [4,13,14]. While the Keratan system on cassava seeds can increase root proliferation so that cassava yields reach 51 tons/ha [5,11,12,1]. Withdrawing cassava seedling stems and mycorrhizal inoculation, cassava yields increased by 54% (54.32 tons/Ha) [3].…”

Microbial Diversity Associated with Photosynthetic Organisms

“…Especially in recent years, the identification and characterization of rhizobacteria in agricultural production is considered to be of great significance. In our Special Issue, Zapata et al [12] isolated 58 rhizobacterial strains from the plant rhizosphere of cassava Manihot esculenta Crantz CIAT MCOL1734 variety subjected to water deprivation, and identified the bacteria belonged to 12 genera: Achromobacter, Acinetobacter, Aeromonas, Buttiauxella, Cronobacter, Klebsiella, Ochrobactrum, Pluralibacter, Pseudomonas, Rhizobium, Serratia, and Sphingomonas. The cassava roots constitute a great reservoir of potential Gram-negative rhizobacteria with remarkable biotechnological applications.…”