Bacterial endophytes in cotton: mechanisms of entering the plant

Quadt-Hallmann, A.; Benhamou, Nicole; Kloepper, Joseph W.

doi:10.1139/m97-081

Cited by 162 publications

(71 citation statements)

References 27 publications

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“…Previous study has shown that active penetration of cotton plants by bacterial endophytes involves the hydrolysis of cellulose, which could induce systemic resistance to pathogens (30). When present within the inner tissue of asymptomatic citrus plants, C. flaccumfaciens could produce compounds or elicit some degree of enhanced resistance in these plants that leads to enhanced resistance to X. fastidiosa.…”

Section: Discussionmentioning

confidence: 99%

Diversity of Endophytic Bacterial Populations and Their Interaction withXylella fastidiosain Citrus Plants

Araújo

Marcon

Maccheroni

et al. 2002

Appl Environ Microbiol

512

354

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Citrus variegated chlorosis (CVC) is caused by Xylella fastidiosa, a phytopathogenic bacterium that can infect all Citrus sinensis cultivars. The endophytic bacterial communities of healthy, resistant, and CVC-affected citrus plants were studied by using cultivation as well as cultivation-independent techniques. The endophytic communities were assessed in surface-disinfected citrus branches by plating and denaturing gradient gel electrophoresis (DGGE). Dominant isolates were characterized by fatty-acid methyl ester analysis as Bacillus pumilus, Curtobacterium flaccumfaciens, Enterobacter cloacae, Methylobacterium spp. (including Methylobacterium extorquens, M. fujisawaense, M. mesophilicum, M. radiotolerans, and M. zatmanii), Nocardia sp., Pantoea agglomerans, and Xanthomonas campestris. We observed a relationship between CVC symptoms and the frequency of isolation of species of Methylobacterium, the genus that we most frequently isolated from symptomatic plants. In contrast, we isolated C. flaccumfaciens significantly more frequently from asymptomatic plants than from those with symptoms of CVC while P. agglomerans was frequently isolated from tangerine (Citrus reticulata) and sweet-orange (C. sinensis) plants, irrespective of whether the plants were symptomatic or asymptomatic or showed symptoms of CVC. DGGE analysis of 16S rRNA gene fragments amplified from total plant DNA resulted in several bands that matched those from the bacterial isolates, indicating that DGGE profiles can be used to detect some endophytic bacteria of citrus plants. However, some bands had no match with any isolate, suggesting the occurrence of other, nonculturable or as yet uncultured, endophytic bacteria. A specific band with a high G؉C ratio was observed only in asymptomatic plants. The higher frequency of C. flaccumfaciens in asymptomatic plants suggests a role for this organism in the resistance of plants to CVC.

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Section: Discussionmentioning

confidence: 99%

Diversity of Endophytic Bacterial Populations and Their Interaction withXylella fastidiosain Citrus Plants

Araújo

Marcon

Maccheroni

et al. 2002

Appl Environ Microbiol

512

354

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“…The possibility that Enterobacter asburiae is a competitor of S. enterica serovar Newport and E. coli O157 on A. thaliana is indicated by the observation that its appearance on the plant was correlated with the highest competition against S. enterica serovar Newport and E. coli O157:H7. Enterobacter asburiae has been reported to be an endophyte and a frequent inhabitant of the rhizosphere of cotton, bean, and cucumber (23,24,39) and to move systemically in the plant (46). Evidence that Enterobacter asburiae inhabits the phyllosphere has not been reported.…”

Section: Discussionmentioning

confidence: 99%

Colonization of Arabidopsis thaliana with Salmonella enterica and Enterohemorrhagic Escherichia coli O157:H7 and Competition by Enterobacter asburiae

Cooley

Miller

Mandrell

2003

Appl Environ Microbiol

265

217

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Enteric pathogens, such as Salmonella enterica and Escherichia coli O157:H7, have been shown to contaminate fresh produce. Under appropriate conditions, these bacteria will grow on and invade the plant tissue. We have developed Arabidopsis thaliana (thale cress) as a model system with the intention of studying plant responses to human pathogens. Under sterile conditions and at 100% humidity, S. enterica serovar Newport and E. coli O157:H7 grew to 10 9 CFU g ؊1 on A. thaliana roots and to 2 ؋ 10 7 CFU g ؊1 on shoots. Furthermore, root inoculation led to contamination of the entire plant, indicating that the pathogens are capable of moving on or within the plant in the absence of competition. Inoculation with green fluorescent protein-labeled S. enterica and E. coli O157:H7 showed invasion of the roots at lateral root junctions. Movement was eliminated and invasion decreased when nonmotile mutants of S. enterica were used. Survival of S. enterica serovar Newport and E. coli O157:H7 on soil-grown plants declined as the plants matured, but both pathogens were detectable for at least 21 days. Survival of the pathogen was reduced in unautoclaved soil and amended soil, suggesting competition from indigenous epiphytes from the soil. Enterobacter asburiae was isolated from soil-grown A. thaliana and shown to be effective at suppressing epiphytic growth of both pathogens under gnotobiotic conditions. Seed and chaff harvested from contaminated plants were occasionally contaminated. The rate of recovery of S. enterica and E. coli O157:H7 from seed varied from undetectable to 19% of the seed pools tested, depending on the method of inoculation. Seed contamination by these pathogens was undetectable in the presence of the competitor, Enterobacter asburiae. Sampling of 74 pools of chaff indicated a strong correlation between contamination of the chaff and seed (P ‫؍‬ 0.025). This suggested that contamination of the seed occurred directly from contaminated chaff or by invasion of the flower or silique. However, contaminated seeds were not sanitized by extensive washing and chlorine treatment, indicating that some of the bacteria reside in a protected niche on the seed surface or under the seed coat.

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“…The beneficial endophytic bacteria may mediate plant adaptation to the environmental stress [53]. PGPR endobacteria alleviate plant stress due to temperature, drought, heavy metal accumulation and solar ultraviolet-B radiation (280-315 nm) [54].…”

Section: Plant Stress Tolerancementioning

confidence: 99%

Exploring the Potential of Endophytes in Agriculture: A Minireview

Yadav¹

2017

APAR

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Bacterial endophytes in cotton: mechanisms of entering the plant

Cited by 162 publications

References 27 publications

Diversity of Endophytic Bacterial Populations and Their Interaction withXylella fastidiosain Citrus Plants

Diversity of Endophytic Bacterial Populations and Their Interaction withXylella fastidiosain Citrus Plants

Colonization of Arabidopsis thaliana with Salmonella enterica and Enterohemorrhagic Escherichia coli O157:H7 and Competition by Enterobacter asburiae

Exploring the Potential of Endophytes in Agriculture: A Minireview

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