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Role of Endophytes, Plant Growth Promoting Rhizobacteria

lanuginosum which contains Curvularia protuberata a fungal endophyte, can

tolerate up to 65°C soil temperature in Yellowstone National Park (Redman

et al., 2002). Fungal endophyte also enhances heat tolerance in Triticum

aestivum and promotes plant height and grain weight (Lata et al., 2018).

3.4.1.4 ENDOPHYTES-MEDIATED HEAVY METAL STRESS TOLERANCE

IN PLANTS

Nowadays, heavy metal contamination in soil and underground water is a

common phenomenon due to expansion of industrialization and urbanization.

Application of chemical fertilizer by the farmers is also increase heavy metal

contamination in soil. Accumulations of heavy metal in the plant body have

several detrimental effects that limit growth. Exophiala pisciphila inhabiting

in maize root limits cadmium (Cd) stress by activating antioxidant enzymes

(Wang et al., 2016). Pseudomonas and Gigaspora can induce metal stress

tolerance by altering the level of ACC deaminase which helps to manipulate

the ethylene levels in plants (Friesen et al., 2011). Tobacco plants inoculated

with Acrocalymma vagum decreased the amount of heavy metals like Cd,

lead (Pb) and Arsenic (As) and also limits the translocation of these heavy

metals in the plant (Jin et al., 2017).

Plants might face more than one stress condition simultaneously. It was

reported that endophytes can improve tolerance in plants against salinity,

drought, and temperature stress simultaneously (Zhang et al., 2019). In Table

3.1, we have presented different endophytic microorganisms that contribute

to plant growth and development under different stress conditions.

3.4.2 ENDOPHYTES-MEDIATED BIOTIC STRESS MANAGEMENT IN

PLANTS

In plants, biotic stresses are mainly characterized by the attack of various

pathogens and insect pests which causes a negative impact on plant growth,

leading to major yield loss. Endophytic microorganisms showed interaction

with fungal pathogens, nematodes, and many other plant pathogens giving

protection to plants (Chadha et al., 2015). In several studies fungal endo­

phytes exhibited significant antimicrobial activity and also inhibit several

plant pathogens through antagonism (Rodrguez et al., 2008). Fungal endo­

phytes are used as biocontrol agents for several pathogenic microbes. For

instance, Penicillium citrinum is used to control the destructive pathogen