Diversity of cultivable bacterial endophytes in Paullinia cupana and their potential for plant growth promotion and phytopathogen control

Abstract

Endophytic bacteria occupy the same niche of phytopathogens and may produce metabolites that induce the host plant systemic resistance and growth. Host and environmental variables often determine the endophytic community's structure and composition. In this study, we addressed whether the plant genotype, organ, and geographic location influence the structure, composition, and functionality of endophytic bacterial communities in Paullinia cupana. To characterize the communities and identify strains with potential application in agriculture, we analyzed two P. cupana genotypes cultivated in two cities of the State of Amazonas, Brazil. Endophytic bacteria were isolated from surface-disinfested root, leaf, and seed tissues through the fragmentation and maceration techniques. The colonization rate, number of bacteria, richness, diversity, and functional traits were determined. The plant growth-promoting ability of selected bacterial strains was assessed in Sorghum bicolor. We identified 95 bacterial species distributed in 29 genera and 3 phyla (Proteobacteria, Actinobacteria, and Firmicutes). The colonization rate, richness, diversity, and species composition varied across the plant organs; the last parameter also varied across the plant genotype and location. Some strains exhibited relevant plant growth-promoting traits and antagonistic traits against the main phytopathogens of P. cupana, but they were not separated by functional traits. The main bacterial strains with plant growth-promoting traits induced S. bicolor growth. Altogether, our findings open opportunities to study the application of isolated endophytic bacterial strains in the bioprospection of processes and products.

Microbial Diversity of Upland Rice Roots and Their Influence on Rice Growth and Drought Tolerance

“…Surface sterilization of the upland rice roots was performed according to a previously described procedure [ 20 , 52 , 53 ]. The root samples were washed under running tap water to remove bulk soil and other loosely attached debris.…”

“…Finally, the sections were rinsed three to five times with sterile distilled water. The endophytic bacteria were isolated using the fragmentation technique [ 53 ]. With respect to fungi, dried root samples were placed onto sterile filter paper, cut into 8–10 mm segments and then placed onto plates of PDA supplemented with antibiotics as mentioned above.…”

Phylogenetic and Functional Characterization of Culturable Endophytic Actinobacteria Associated With Camellia spp. for Growth Promotion in Commercial Tea Cultivars

“…Unsterilized soil was used in the experiment to determine the effects of these bacterial strains on tea clones in competition with the naturally occurring soil microbes. The tea clones were treated with 10 ml cell suspension by soil drenching at one-month intervals for three months and watered with sterile distilled water daily (Liotti et al, 2018;Zhao et al, 2018). All vegetative parameters such as shoot length, root length, shoot fresh and dry weight and root fresh, dry weight, chlorophyll content and soil parameter analysis were recorded and compared to control (Dutta et al, 2015b;Dutta and Thakur, 2017).…”

Appraising Endophyte–Plant Symbiosis for Improved Growth, Nodulation, Nitrogen Fixation and Abiotic Stress Tolerance: An Experimental Investigation with Chickpea (Cicer arietinum L.)

“…Acinetobacter, Agromyces, Azoarus, Bacillus, Brevibacillus, Brevundimonas, Burkholderia, Comamonas, Corynebacterium, Delftia, Dietzia, Enterobacter, Frigoribacterium, Kocuria, Lysinibacillus, Methylobacterium, Microbacterium, Micrococcus, Paenibacillus, Pantoea, Pseudomonas, Rhizobium, Rhodococcus, Serria, Sphingobacterium, Sphingomonas, Sporosarcina, Staphylococcus, Stenotrophomonas, Xanthomonas, etc. [7,[12][13][14][15][16][17][18][19][20][21][22]. All of these described bacterial endophytic genera are also common inhabitants of the rhizosphere [7,8].…”