Variability and interactions between endophytic bacteria and fungi isolated from leaf tissues of citrus rootstocks

Abstract

Fungi and bacteria were isolated from surface disinfected leaf tissues of several citrus rootstocks. The principal bacterial species isolated were Alcaligenes sp., Bacillus spp. (including B. cereus, B. lentus, B. megaterium, B. pumilus, and B. subtilis), Burkholderia cepacia, Curtobacterium flaccumfaciens, Enterobacter cloacae, Methylobacterium extorquens, and Pantoea agglomerans, with P. agglomerans and B. pumilus being the most frequently isolated species. The most abundant fungal species were Colletotrichum gloeosporioides, Guignardia citricarpa, and Cladosporium sp. Genetic variability between 36 endophytic bacterial isolates was analysed by the random amplified polymorphic DNA (RAPD) technique, which indicated that B. pumilus isolates were more diverse than P. agglomerans isolates, although genetic diversity was not related to the host plants. In vitro interaction studies between G. citricarpa isolates and the most frequently isolated endophytic bacteria showed that metabolites secreted by G. citricarpa have an inhibitory growth effect on some Bacillus species, and a stimulatory growth effect on P. agglomerans.

Bacteriosomes in axenic plants: endophytes as stable endosymbionts

“…is in line with data from the literature describing the isolation of these species from microplants (Vivas et al 2003a, b;Vivas et al 2005;Thomas 2006). Araújo et al (2001) described the colonization of Citrus jambhiri root xylem by endophytes, and remarked the establishment of bacterial cells in the apoplastic or inside of the vessels cells.…”

Coinoculation of Bacillus thuringeinsis-KR1 with Rhizobium leguminosarum enhances plant growth and nodulation of pea (Pisum sativum L.) and lentil (Lens culinaris L.)

“…Nonrhizobial occupants are usually considered to be endophytes, but the definition of the word endophyte has been much debated. Bacillus species are often encountered as endophytes within plant tissues (Kobayashi and Palumbo 2000;Araujo et al 2001), Sturz et al (2000) isolated 32 endophytic bacteria from red clover, of which six Bacillus species were present viz., Bacillus azotoformans, ND not detected; LSD least significant difference; SEM ± standard error of mean difference a All values are Mean ± SD of three replicates (three plants in each replicate) b The population of Rhizobium leguminosarum-PR1 was 1.10 9 10 7 c.f.u. ml -1 in all the treatments c Values followed by different letters in the same column indicate significant difference (P \ 0.05) according to DMRT analysis Bacillus brevis, Bacillus circulans, Bacillus insolitus, Bacillus megaterium, and Bacillus subtilis and four of these were resident within root nodules.…”

Cultivable bacteria isolated from apple trees cultivated under different crop systems: Diversity and antagonistic activity against Colletotrichum gloeosporioides

“…Our results indicated that bacteria belonging to the Enterobacteriaceae family were the most abundant in association with the roots of apple trees. Strains belonging to the Enterobacteriaceae family have also been found to be associated with a large number of plant species, such as citrus (Araújo et al , 2001), maize (Hinton and Bacon, 1995; McInroy and Kloepper, 1995), rice (Engelhard et al , 2000; Gyaneshwar et al , 2001; Rosenblueth et al , 2004; Verma et al , 2004), sweet potato (Asis and Adachi, 2003; Reiter et al , 2003), soybean (Kuklinsky-Sobral et al , 2004), and wheat (Iniguez et al , 2005). …”