title: Impact of endophytic colonization patterns on Zamioculcas zamiifolia stress response and in regulating ROS, tryptophan and IAA levels under airborne formaldehyde and formaldehyde-contaminated soil conditions.
abstract: Deeper understanding of plant-endophyte interactions under abiotic stress would provide new insights into phytoprotection and phytoremediation enhancement. Many studies have investigated the positive role of plant-endophyte interactions in providing protection to the plant against pollutant stress through auxin (indole-3-acetic acid (IAA)) production. However, little is known about the impact of endophytic colonization patterns on plant stress response in relation to reactive oxygen species (ROS) and IAA levels. Moreover, the possible effect of pollutant phase on plant stress response is poorly understood. Here, we elucidated the impact of endophytic colonization patterns on plant stress response under airborne formaldehyde compared to formaldehyde-contaminated soil. ROS, tryptophan and IAA levels in the roots and shoots of endophyte-inoculated and non-inoculated plants in the presence and absence of formaldehyde were measured. Strain-specific quantitative polymerase chain reaction (qPCR) was used to investigate dynamics of endophyte colonization. Under the initial exposure to airborne formaldehyde, non-inoculated plants accumulated more tryptophan in the shoots (compared to the roots) to synthesize IAA. However, endophyte-inoculated plants behaved differently as they synthesized and accumulated more tryptophan in the roots and, hence, higher levels of IAA accumulation and exudation within roots which might act as a signaling molecule to selectively recruit B. cereus ERBP. Under continuous airborne formaldehyde stress, higher levels of ROS accumulation in the shoots pushed the plant to synthesize more tryptophan and IAA in the shoots (compared to the roots). Higher levels of IAA in the shoots might act as the potent driving force to relocalize B. cereus ERBP from roots to the shoots. In contrast, under formaldehyde-contaminated soil, B. cereus ERBP colonized root tissues without moving to the shoots since there was a sharp increase in ROS, tryptophan and IAA levels of the roots without any significant increase in the shoots. Pollutant phase affected endophytic colonization patterns and plant stress responses differently.
authors.affiliation: School of Bioresources and Technology, King Mongkut's University of Technology Thonburi, Bangkok 10150, Thailand. Electronic address: Gholamreza.biotech@mail.kmutt.ac.th.
authors.forename: Gholamreza
authors.initials: G
authors.lastname: Khaksar
authors.affiliation: Pilot Plant Development and Training Institute, King Mongkut's University of Technology Thonburi, Bangkok 10150, Thailand. Electronic address: Chairat.tre@kmutt.ac.th.
authors.forename: Chairat
authors.initials: C
authors.lastname: Treesubsuntorn
authors.affiliation: School of Bioresources and Technology, King Mongkut's University of Technology Thonburi, Bangkok 10150, Thailand. Electronic address: paitip.thi@kmutt.ac.th.
authors.forename: Paitip
authors.initials: P
authors.lastname: Thiravetyan
mesh_terms: D000393:Air Pollutants / Q000633:toxicity; D029064:Araceae / Q000187:drug effects / Q000502:physiology*; D001409:Bacillus cereus / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D002734:Chlorophyll / Q000378:metabolism; D060026:Endophytes / Q000187:drug effects / Q000502:physiology*; D005557:Formaldehyde / Q000633:toxicity; D007210:Indoleacetic Acids / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects / Q000378:metabolism / Q000382:microbiology; D018520:Plant Shoots / Q000187:drug effects / Q000378:metabolism / Q000382:microbiology; D054046:Plant Stomata / Q000187:drug effects / Q000502:physiology; D017382:Reactive Oxygen Species / Q000378:metabolism*; D012989:Soil Pollutants / Q000633:toxicity; D013312:Stress, Physiological / Q000187:drug effects*; D014364:Tryptophan / Q000378:metabolism
chemical_list: D000393:Air Pollutants; D007210:Indoleacetic Acids; D017382:Reactive Oxygen Species; D012989:Soil Pollutants; D002734:Chlorophyll; D005557:Formaldehyde; C030737:indoleacetic acid; D014364:Tryptophan
keywords: Bacillus cereus ERBP; Dynamics of endophyte colonization; Indole-3-acetic acid (IAA); Plant-endophyte interactions; Pollutant phase; Reactive oxygen species (ROS)