Endophytic bacterial communities in the periderm of potato tubers and their potential to improve resistance to soil‐borne plant pathogens

Abstract

To evaluate whether the location of bacterial endophyte communities contributes to disease resistance in potato tubers (Solanum tuberosum), the population density, biodiversity and antibiotic activity of endophytic bacteria was examined from the tuber peel (periderm plus top 3 mm of tissue) of four cultivars (Russet Burbank, Kennebec, Butte and Shepody). There were no significant differences for population density of bacteria among the layers of peel examined and no cultivar × peel layer interaction. Endophytic bacteria from several layers of peel were challenged in in vitro bioassays to the soil-borne plant pathogens Fusarium sambucinum, Fusarium avenaceum, Fusarium oxysporum and Phytophthora infestans (mating types A1 and A2). In general, antibiosis of bacterial endophytes against these pathogens was significantly higher (P ¼ 0·01) in isolates recovered from the outermost layer of tuber peel and decreased progressively toward the centre of the tuber. Antibiosis against P. infestans was variable, with a progressive decrease in antibiotic activity from outer to inner layers of peel occurring in cvs Russet Burbank and Kennebec only. For antibiosis there were significant cultivar × peel, and cultivar × pathogen interactions (P ¼ 0·01). In all cases the inhibitory activity of endophytic bacteria was significantly greater (P ¼ 0·01) against the A1 than the A2 mating type of P. infestans. In four of seven cases, where the same species of bacteria were recovered from all three peel layers, antibiosis to pathogens decreased significantly (P ¼ 0·01) with depth of recovery (from the periderm to inside the tuber), indicating that in certain communities of endophytic bacteria, defence against pathogens may be related to bacterial adaptation to location within a host and may be tissue-type and tissue-site specific.

Vanilla Rhizobacteria as Antagonists against Fusarium oxysporum f. sp. vanillae

“…Evaluation of germinated spores of F. oxysporum showed morphological changes such as protuberances in the hyphae which prevented cell differentiation at the ends of the hyphae and contributed to stopping or slowing mycelial elongation (Matsuda et al, 2001). These results agree with those obtained by Sturz et al (1999) who reported on the antifungal ability of the bacterial species Sphingobacterium thalpophilum and Psychrobacter immobilis against Fusarium sambucinum, F. avenaceum and F. oxysporum to slightly inhibit in vitro growth.…”

Response of endophytic bacterial communities in banana tissue culture plantlets to Fusarium wilt pathogen infection

“…Bacterial endophytes have been isolated from many different plant species, including tomato (Nejad and Johnson, 2000), potato (Garbeva et al, 2001;Sturz et al, 1999), wheat (Coombs and Franco, 2003;Germida et al, 1998;Siciliano et al, 1998), sweet corn (McInroy and Kloepper, 1995), cotton (McInroy and Kloepper, 1995), Vol. 54 LIAN,WANG,and ZHOU oilseed rape Nejad and Johnson, 2000), coffee (Fernando et al, 2005), sugarcane (James and Olivares, 1998) and citrus plants (Araujo et al, 2001(Araujo et al, , 2002.…”

“…Several bacterial endophytes have been reported to support growth and improve the health of plants (Benhamou et al, 1996;Chen et al, 1995;Coombs et al, 2004;Sturz et al, 1999) and therefore may be important sources of biocontrol agents. The widely recognized mechanisms of biocontrol mediated by endophytes are competition for an ecological niche or a substrate, production of inhibitory allelochemicals, and induction of systemic resistance (ISR) in host plants to a broad spectrum of pathogens (Hallmann et al, 1997;Lodewyckx et al, 2002;Sturz et al, 2000) and/or abiotic stresses (Compant et al, 2005).…”

Beneficial microbiomes: Biodiversity and potential biotechnological applications for sustainable agriculture and human health

“…Endophytic microbes exist within the living tissues of most plant species in the form of symbiotic to slightly pathogenic. A large number of endophytic microbial species such as Achromobacter, Burkholderia, Burkholderia, Curtobacterium, Enterobacter, Gluconoacetobacter, Herbaspirillum, Klebsiella, Microbiospora, Nocardioides, Pantoea, Planomonospora, Pseudomonas, Serratia, and Streptomyces have been identified from different host plants [22,[28][29][30][31][32][33].…”