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Biology and Biotechnology of Environmental Stress Tolerance in Plants, Volume 3

processes. Plant-endophyte synergism is important for plant development,

growth, and fitness, as well as contaminated soil decontamination. The

endophyte Pseudomonas putida PD1 was shown to enhance root and shoot

development as well as protect plants against phenanthrene phytotoxicity in

two distinct willow clones and a grass (Khan et al., 2014). The expression

of degrading genes was found to be high in endophyte colonization that was

successful (Jabeen et al., 2016).

Since plants do not procure their carbon from organic pollutants thus, they

rely on the endophytes for their degradation. Endophytic bacteria create diverse

enzymes to mineralize organic pollutants and reduce both phytotoxicity and

evapotranspiration of volatile organic pollutants during phytoremediation of

organic pollutants (Wang & Dai, 2011). For the first time, endophytic bacteria

were used to clean up soil that had been contaminated by the organochlorine

pesticide 2,4-dichlorophenoxyacetic acid (2,4-D) (Germaine et al., 2006;

Afzal, Khan, & Sessitsch, 2014). Pseudomonas sp. BF1-3, a root endophyte

with the organophosphorus hydrolase gene ophB, can easily hydrolyze

chlorpyrifos (Barman et al., 2014). Burkholderia phytofirmans PsJN, an

endophyte, has glutathione-S-transferase (GST) genes that help it degrade

and detoxify complex chemical substances (Mitter et al., 2013). Chelating

agents, siderophores, biosurfactants, low molecular weight organic acids, and

other detoxifying enzymes are all produced by certain endophytes and are all

beneficial for eliminating organic pollutants from soils (Li et al., 2012). Pesta­

lotiopsis palmarum BM-04, a powerful remediating endophytic fungus, can

withstand high salinity and crude oil contamination (Naranjo-Briceño et al.,

2013). PAH and total petroleum hydrocarbon (TPH) clearance were 80–84%

and 64–72% in the plant rhizosphere, respectively, and TPH removal was

higher in endophyte-infected plants than in non-infected plants (Soleimani

et al., 2010; Nandy et al., 2020). Phomopsis liquidambaris could not only

respond to phenanthrene pollution stress in vitro, but it could also mitigate

the effects of phenanthrene accumulation in plants (Fu et al., 2018). Table 1.4

lists the endophytes involved in the detoxification of organic contaminants.

1.6 NEMATODES: AS INDICATORS AND AMELIORANTS OF HEAVY

METAL CONTAMINATED SOILS

Nematodes are one of the most abundant multicellular animals on earth widely

distributed in various soil habitats, with a total estimated population reaching

to around 4.4 × 10²⁰ (with a total biomass of approximately 0.3 gigatons) in

the surface soil (van den Hoogen et al., 2019). Nematodes are found to play a