Survey of indigenous bacterial endophytes from cotton and sweet corn

Abstract

The genotypic diversity of indigenous bacterial endophytes within stems and roots of sweet corn (Zea mays L.) and cotton (Gossypium hirsutum L.) was determined in field trials throughout one growing season. Strains were isolated from surface-disinfested tissues and identified by fatty acid analysis. Gram-negative bacteria comprised 70.5% of the endophytic bacteria and 27 of the 36 genera identified. The most frequently isolated groups from sweet corn roots, were Burkholderia pickettii and Enterobacter spp.; from sweet corn stems, Bacillus megaterium. Bacterial genera present in sweet corn roots were also generally present in sweet corn stems. However, Burkholderia gladioli, Burkholderia solanacearum and Enterobacter cloacae were isolated much more frequently from sweet corn roots than stems, whereas Methylobacterium spp. were found more frequently in sweet corn stems than roots. Agrobacterium radiobacter, Serratia spp. andBurkholderia solanacearum, were the most frequently isolated groups from cotton roots; and Bacillus megaterium and Bacillus pumilus from cotton stems. Acinetobacter baumannii and Arthrobacter spp. were present in cotton stems but not in cotton roots. There were 14 taxonomic groups present in cotton roots that were not in cotton stems; all but one were Gram-negative. These included, Agrobacterium radiobacter, Bacillus megaterium, Bacillus pumilus, Enterobacter asburiae, Pseudomonas chlororaphis, Serratia spp. and Staphylococcus spp. Rhizobium japonicum and Variovorax paradoxus were isolated, almost exclusively, from the roots of both crops. Bacterial taxa present in both sweet corn and cotton early in the season were generally present late in the season. The diversity of bacteria was greater in roots than stems for each crop.

Enzymatic activity of endophytic bacterial isolates of Jacaranda decurrens Cham. (Carobinha-do-campo)

“…The bacteria that live in the interior of plants without causing diseases to their hosts are called endophytic (Petrini et al, 1989;Azevedo et al, 2000). Endophytic microorganisms have been isolated from different types of vegetation such as grass (Naffaa et al, 1998), corn McInroy and Kloepper, 1995), Eriaceae (Petrini, 1984), cotton (McInroy and Kloepper, 1995), bryophytes (Costa et al, 2001), Solanum lycocarpum (Maitan, 1998) and agricultural crops (Halmann et al, 1997). Studies for the isolation and characterization of endophytic microorganisms of native plant specimens from Brazilian Cerrado biome are rare.…”

Stenotrophomonas rhizophila sp. nov., a novel plant-associated bacterium with antifungal properties.

“…Harvesting, saponification, methylation and extraction of fatty acid methyl esters were performed according to Sasser (1990). Identification of the fatty acid methyl esters was performed by GC-MS as described by McInroy & Kloepper (1995). Data on the fatty acids from S. nitritireducens strains were analysed by Finkmann et al (2000).…”

Identification of Volatile Metabolites from Fungal Endophytes with Biocontrol Potential towards <i>Fusarium oxysporum</i> F. sp. <i>cubense</i> Race 4

“…Endophytes are most often isolated from symptomless plants of various species (McInroy and Kloepper, 1995). Their association with host plants are known to improve plant growth and vigour (Ting et al, 2008), enhance plant nutrient absorption (Chanway, 1996) and to potentially confer disease resistance in plants against pathogen infection (Ting et al, 2007).…”