Endophytic bacteria in cacti native to a Brazilian semi-arid region

Abstract

Aim To identify endophytic bacteria in Brazilian cacti, and to evaluate the effects of those bacteria on the growth of Cereus jamacaru seedlings and phosphate solubilization in vitro. Methods Samples of roots and stems of C. jamacaru and Melocactus zehntneri were collected from the Aiuaba ecological Station in Brazilian semi-arid region. Bacterial isolates were cultured in semi-solid N-free media and grown in Pikoskaya's and GL media phosphate solubilizing. In seedling assays, strains of Rhizobium (CAC 01), Enterobacter (CAC 02 and CAC 11), Pseudomonas (CAC 03) and Burkholderia (CAC 07 and CAC 10) were tested. Results Culturable endophytic bacteria were observed in all samples from cacti, but the populations were low.Representatives of eight groups were identified based on partial sequences of 16S rDNA and were related to Rhizobium, Burkholderia, Enterobacter, Pseudomonas, and Pantoea species. The colonization of seedlings with endophytic bacteria was observed, but biomass accumulation did not show a significant increase. All strains were able to grow on solid Pikoskaya's medium. Conclusions The bacterial strains didn't increase significantly the cactus biomass during 6 months of cultivation, but showing potential phosphate solubilizing activity.

Evaluation of the plant-growth-promoting abilities of endophytic bacteria from the psammophyteAmmodendron bifolium

“…In the case of the tomato plants, germination and radicle length were found to be 6 -17% and 0.2 -0.7 times by paper towel method (Hariprasad and Niranjana 2009). For cacti grown in semi-arid region, its seedlings growth was not significantly increased after endophytic bacterial colonization in artificially prepared soil (Lima et al 2015). Although A. bifolium endophytic bacteria had obvious D r a f t growth-promoting effects on seed germination and radicle growth, the effects of these strains on seedling growth and other growth stage still need further investigation.…”

Bacterias y hongos endófitos de la familia Cactaceae y sus aplicaciones

“…A pesar de que las PGPB son esenciales para el establecimiento de plantas en zonas áridas y semiáridas, falta más investigación sobre su presencia en las cactáceas. Lima, Weber, Correia, Soares & Senabio (2015) identificaron en la cactácea columnar Cereus jamacaru DC., cepas bacterianas como Rhizobium, Burkholderia, Enterobacter, Pseudomonas y Pantoea, que no aumentaron significativamente la biomasa del cactus durante seis meses de cultivo, sin embargo, estas bacterias mostraron una posible actividad solubilizadora de fosfatos.…”

“…y Pilosocereus gounellei (F.A.C.Weber ex K.Schum.) Byles & G. D. Rowley, algunos de estos géneros (Bacillus, Enterobacter, Pantoea) también se han identificado como endófitos de cactáceas López et al, 2012;Lima et al, 2015;Fonseca-García et al, 2018). El 65% de esas cepas bacterianas crecieron en un medio con reducida disponibilidad de agua y un 65% produjeron exopolisacáridos.…”

Composition, Structure, and PGPR Traits of the Rhizospheric Bacterial Communities Associated With Wild and Cultivated Echinocactus platyacanthus and Neobuxbaumia polylopha

“…Recently, the effect of soil contamination by Zn on the diversity of the microbiota associated with Echinocactus platyacanthus was analyzed to explain its high tolerance to environmental stress ( Sarria-Carabali et al, 2019 ). While in Brazil Lima et al (2015) characterized endophytic bacteria isolated from Cereus jamacaru and Melocactus zehntneri . Kavamura et al (2013) focused on the cultivable fraction of drought-tolerant bacteria associated with cacti from the arid Caatinga region.…”