Fig. 2.

Endophyte-Induced systemic resistance (ISR) in rice. ISR conventionally depends on JAs and ethylene signalling. Endophytes, through production of siderophores such as pseudobactin and pigments like pyocyanin, induce robust cellular defences against pathogens (De Vleesschauwer et al. 2006, 2008); while through other unknown mechanisms, they impair development, fecundity and population size of rice pathogens (Le et al. 2016). They also promote plant growth but inhibit pathogen growth through regulating the expression of rice genes involved in ethylene signalling such as ethylene responsive factor1 (OsERF1), ETHYLENE INSENSITIVE 3-like 1 (EIL1), and JAs signalling such as jasmonate resistant1 (JAR1), tryptophan-arginine-lysine-tyrosine30 (WRKY30) (Spence et al. 2014). The nonconventional salicylic acid (SA)-dependent endophyte-ISR in rice can occur either through repressing JA-signalling pathway by downregulating JAmyb (Lee et al. 2001), or through NON-EXPRESSOR of PR1 (OsNPR1)- and OsWRKY45-mediated signalling pathways (Su et al. 2013; Ashajyothi et al. 2020), leading to the inhibition of pathogen growth on account of H₂O₂ burst, altered plant morphology, and phenolics production