Isolation and Characterization of Endophytic Colonizing Bacteria from Agronomic Crops and Prairie Plants

Abstract

Endophytic bacteria reside within plant hosts without causing disease symptoms. In this study, 853 endophytic strains were isolated from aerial tissues of four agronomic crop species and 27 prairie plant species. We determined several phenotypic properties and found approximately equal numbers of gram-negative and gram-positive isolates. In a greenhouse study, 28 of 86 prairie plant endophytes were found to colonize their original hosts at 42 days postinoculation at levels of 3.5 to 7.7 log 10 CFU/g (fresh weight). More comprehensive colonization studies were conducted with 373 corn and sorghum endophytes. In growth room studies, none of the isolates displayed pathogenicity, and 69 of the strains were recovered from corn or sorghum seedlings at levels of 8.3 log 10 CFU/plant or higher. Host range greenhouse studies demonstrated that 26 of 29 endophytes were recoverable from at least one host other than corn and sorghum at levels of up to 5.8 log 10 CFU/g (fresh weight). Long-range dent corn greenhouse studies and field trials with 17 wild-type strains and 14 antibioticresistant mutants demonstrated bacterial persistence at significant average colonization levels ranging between 3.4 and 6.1 log 10 CFU/g (fresh weight) up to 78 days postinoculation. Three prairie and three agronomic endophytes exhibiting the most promising levels of colonization and an ability to persist were identified as Cellulomonas, Clavibacter, Curtobacterium, and Microbacterium isolates by 16S rRNA gene sequence, fatty acid, and carbon source utilization analyses. This study defines for the first time the endophytic nature of Microbacterium testaceum. These microorganisms may be useful for biocontrol and other applications.

Diversity of bacterial endophytes in roots of Mexican husk tomato plants (Physalis ixocarpa) and their detection in the rhizosphere

“…Some studies have reported species of Stenotrophomonas as a plant growth-promoting bacterium that can suppress disease development by secretion of some compounds, such as the antibiotic maltophilin (Jakobi et al, 1996). The second most dominant group was Microbacterium sp, which has been reported in endophytic association with different plants and maize kernels (Zinniel et al, 2002;Conn and Franco, 2004;Rijavec et al, 2007). In fact, Conn and Franco (2004) reported several Microbacterium species in an analysis of the endophytic populations in the roots of wheat (Triticum aestivum L.), being the predominant genus.…”

Isolation and characterization of endophytic bacteria fromPlectranthus tenuiflorusmedicinal plant in Saudi Arabia desert and their antimicrobial activities

“…for stems, leaves, and roots. The disinfectant was removed by rinsing five times each in two washes of sterile distilled water and finally in sterile water and plant parts were dried on sterile paper towels Zinniel et al 2003) dissected into 1 cm pieces and then pressed onto nutrient agar as a disinfestations control. To confirm that the disinfection process was successful, the plant organs pieces were pressed onto TSA medium plates and aliquots of the sterile distilled water used in the final rinse were also plated onto the same medium.…”

Viability of Probiotics in Feed under High Temperature Conditions and Their Growth Inhibitory Effect on Contaminant Microbes

“…식물병원균으로 알려진 Pantoea ananatis는 식물이나 토양에서 분리되며 (Coutinho and Venter, 2009), Paenibacillus soli는 토 양에서 xylanase 효소를 분비하는 균으로 분리되었다 (Park et al, 2007). C. citreum는 벼논이나 사막의 먼지로부터 분리되고 있으나, 그 기능은 아직 잘 알려져 있지 않고 있다 (Zinniel et al, 2002). S. saprophyticus는 여성의 요로감염과 소의 유방염에서 고온 조건에서 사료 내 생균제의 생존성 및 오염미생물 349 분리되는 병원균이며 (Raz et al, 2005;Bhasme et al, 2013), S.…”