Genome Analysis Of Endophytic Escherichia Coli USML2 And Its In Planta Ascending Migration With Growth Promoting Effect
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Date
2018-01
Authors
Tharek, Munirah
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
The discovery of E. coli USML2 from inner leaf tissues of healthy oil palm
(Elaeis guineensis Jacq.) raised several questions regarding its presence in planta and
benefits to the host plant. Therefore, the ability of E. coli USML2 to migrate from
roots into internal leaf tissues of rice seedlings and promote growth of its host plant
was investigated. Subsequently, analysis of E. coli USML2 genome was performed
to elucidate genes related to in planta ascending migration and plant growth
promotion. Finally, importance of in planta migration towards plant growth
promotion was also studied. Based on the results, E. coli USML2 colonized the root
surface and internal tissues of root, stem and leaf within 24 h of inoculation. Results
also indicated an infection pattern initiated from root surface colonization, invasion
of the internal root system followed by bacteria migration into the stem and leaf
tissues. Interestingly, E. coli USML2 inoculation exhibited significant increase of
leaf numbers (33.3%), chlorophyll content (33.3%), shoot height (34.8%) and plant
dry weight (90.4%) of 42-days-old rice seedlings as compared to the negative
control. Furthermore, analysis of E. coli USML2 genome revealed genes encoding
for bacteria movement towards the root (flagella, chemotaxis), root adhesion (pili,
quorum sensing, extracellular polymeric substances), invasion (cellulose and pectin
degradation enzymes) and plant growth promotion (nitrogen, phosphorus, potassium,
IAA, ACC, acetoin, siderophore, trehalose, sulphur, magnesium transporter,
chorismate, choline, taurine, riboflavin, pyridoxine, phenylpropanoids, membrane
transporters). Interestingly, genomic island predicted several in planta ascending
migration (pili, EPS) and plant growth promotion (magnesium transporter, mgtC)
genes. Additionally, genes involved in adhesion (uncharacterized protein YdeU and
an outer membrane autotransporter barrel-domain containing protein) were among 24
unique genes in E. coli USML2.
Description
Keywords
Escherichia coli USML2 in planta ascending migration , with growth promoting effect