Elevated expression of hydrolases, oxidase, and lyase in susceptible and resistant cucumber cultivars systemically induced with plant growth-promoting fungi against anthracnose

Abstract

Susceptible and resistant cultivars of cucumber (cv. Suyo and cv. Shogoin fushinari, respectively) were evaluated for induction of systemic resistance by plant growth-promoting fungal isolates Phoma sp. GS8-1 and nonsporulating fungus GU21-2 against Colletotrichum orbiculare. Reduction in anthracnose disease was assessed at regular intervals of 0, 3, 6, and 9 days after challenge inoculation. Activities of endochitinase, β-1, 3-endoglucanase, peroxidase (PO), polyphenol oxidase, and phenylalanine ammonia lyase (PAL) were assayed at the above intervals, while the activities of exochitinase and β-1,3-exogluconase were assayed at 9 days after challenge inoculation. The data showed that all the enzymes activities increased in plants treated with plant growth-promoting fungi (PGPF) compared with nontreated plants of both cultivars. The activities of endochitinase and β-1,3-endoglucanase were highly increased in PGPF-induced plants than in nontreated plants of both cultivars at different time points. Activities of PO, polyphenol oxidase, and PAL also increased between 3 and 6 days due to inoculation with PGPF and decreased thereafter. The activity of PAL at 9 days in PGPF-induced plants was at the same level as that of nontreated plants of both cultivars. Results of this investigation suggest that PGPF-induced systemic resistance is associated with not only high increases in the activities of chitinase and β-1,3-gluconases but also other plant defense-related enzymes such as PO, PPO, and PAL. Roles of other mechanisms rather than accumulation of defense-related enzymes in PGPF-mediated induced resistance in susceptible cultivars were demonstrated.

Induction of systemic resistance againstPapaya ring spot virus(PRSV) and its vectorMyzus persicaebyPenicillium simplicissimumGP17-2 and silica (Sio2) nanopowder

“…Certain beneficial microorganisms such as plant growth-promoting fungi (PGPF) have received great attention in the past few years due to not only promoting plant growth but also motivating the plant systemic resistance against different plant pathogens (Van Loon et al 1998;Elsharkawy et al 2014Elsharkawy et al , 2015Hassan et al 2014), nematode pests (Sikora 1988) and insect pests (Zehnder et al 1997). Recently, PGPF have been shown to induce systemic resistance in cucumber (Elsharkawy et al 2012b).…”

Incidence of kernel smut caused by Tilletia barclayana in Egyptian rice cultivars

“…In the present study, an increment in the defenserelated enzymes, that are, POX and PPO and total protein contents was observed in rice cultivars as a result of inoculation with T. barclayana. Among induced defense responses, production and accumulation of pathogensis related proteins are very important (Van Loon et al, 2006;Elsharkawy et al, 2012a, b;Elsharkawy et al, 2013;Hassan et al, 2014). Attempts have been made to exploit these anti-fungal proteins to develop disease resistant transgenic crop plants (Lin et al, 1995;Tabei et al, 1997).…”

“…It was reported that plants defend themselves from the invader pathogens by either their structural barriers or antimicrobial compound which prevent colonization of the tissues. The induced defense responses include hypersensitive responses, the production of reactive oxygen species (ROS), pathogensis-related protein and ion fluxes across the plasma membrane (Zhao et al, 2005;Elsharkawy et al, 2012a, b;Elsharkawy et al, 2013;Hassan et al, 2014).…”

Induced systemic resistance against Cucumber mosaic virus by Phoma sp. GS8‐2 stimulates transcription of pathogenesis‐related genes in Arabidopsis

“…Plant growth promoting fungi (PGPF) are a group of non‐pathogenic soil living saprophytes. It was reported that PGPF improve growth with the ability to manage plant diseases . Several strategies were investigated to control the pathogens by biological means.…”