Cultivable endophytic bacteria from leaf bases of Agave tequilana and their role as plant growth promoters

Abstract

Agave tequilana Weber var. ‘Azul’ is grown for the production of tequila, inulin and syrup. Diverse bacteria inhabit plant tissues and play a crucial role for plant health and growth. In this study culturable endophytic bacteria were extracted from leaf bases of 100 healthy Agave tequilana plants. In plant tissue bacteria occurred at mean population densities of 3 million CFU/g of fresh plant tissue. Three hundred endophytic strains were isolated and 16s rDNA sequences grouped the bacteria into eight different taxa that shared high homology with other known sequences. Bacterial endophytes were identified as Acinectobacter sp., A. baumanii, A. bereziniae, Cronobacter sakazakii, Enterobacter hormaechei, Bacillus sp. Klebsiella oxytoca, Pseudomonas sp., Enterococcus casseliflavus, Leuconostoc mesenteroides subsp. mesenteroides and Gluconobacter oxydans. Isolates were confirmed to be plant growth promoting bacteria (PGPB) by their capacities for nitrogen fixation, auxin production, phosphate solubilization, or antagonism against Fusarium oxysporum AC132. E. casseliflavus JM47 and K. oxytoca JM26 secreted the highest concentrations of IAA. The endophyte Acinectobacter sp. JM58 exhibited the maximum values for nitrogen fixation and phosphate solubilization index (PSI). Inhibition of fungi was found in Pseudomonas sp. JM9p and K. oxytoca JM26. Bacterial endophytes show promise for use as bio-inoculants for agave cultivation. Use of endophytes to enhance cultivation of agave may be particularly important for plants produced by micropropagation techniques, where native endophytes may have been lost.

Effect of plant growth-promoting bacteria on the growth and fructan production of Agave americana L.

“…Recently, endophytic bacteria belonging to the genera Acinetobacter , Bacillus and Pseudomonas with a capacity for nitrogen fixation, auxin production and phosphate solubilization were isolated from blue agave plants ( A. tequilana ) from Nayarit, Mexico. 7 Pseudomonas putida M5TSA, isolated from an endemic cactus Mammillaria fraileana that grows in the Sonoran Desert, solubilized inorganic phosphate and demonstrated rock-weathering capacity. 47 These pseudomonads are characterized by biochemical mechanisms and specific enzymes that facilitate rock degradation, as well as the biosynthesis of important secondary metabolites, under varied biotic and abiotic stress conditions.…”

“…In another study, bacterial endophytes isolated from A. tequilana leaves showed the capacity for nitrogen fixation, auxin production, and phosphate solubilization and also increased inulin production. 7 …”

“…Pseudomonas showed positive IAA production, phosphate solubilization, and antagonistic activities against Fusarium oxysporum and Rhizoctonia solani compared to other strains. 6 Martínez-Rodriguez et al 7 also reported that cultivable endophytic bacteria from the leaf base of Agave tequilana Weber var. Blue have the potential to enhance plant growth.…”

Complete Genome Sequence of Klebsiella oxytoca Strain JKo3

“…Klebsiella oxytoca is a free-living bacterium that can be isolated from various plants and animals, including humans. The species can be either pathogenic or beneficial depending on conditions, because it occasionally causes colitis in humans but also promotes the growth of plants and insects as an endophytic diazotroph (1–9). These bilateral characteristics of the species require further elucidation.…”

Phosphate‐solubilizing bacteria improve Agave angustifolia Haw. growth under field conditions

“…found an increase in plant stem diameter, root length, plant leaf number, total root dry weight, shoot dry weight, and total agave plant weight after inoculation of individual indigenous isolates of PSB under glasshouse conditions. Martínez‐Rodriguez et al . also reported that cultivable endophytic bacteria from the leaf base of Agave tequilana Weber var.…”