Inducible and constitutive expression of an elicitor gene Hrip1 from Alternaria tenuissima enhances stress tolerance in Arabidopsis

Abstract

Hrip1 is a novel hypersensitive response-inducing protein secreted by Alternaria tenuissima that activates defense responses and systemic acquired resistance in tobacco. This study investigates the role that Hrip1 plays in responses to abiotic and biotic stress using transgenic Arabidopsis thaliana expressing the Hrip1 gene under the control of the stress-inducible rd29A promoter or constitutive cauliflower mosaic virus 35S promoter. Bioassays showed that inducible Hrip1 expression in rd29A∷Hrip1 transgenic lines had a significantly higher effect on plant height, silique length, plant dry weight, seed germination and root length under salt and drought stress compared to expression in 35S∷Hrip1 lines and wild type plants. The level of enhancement of resistance to Botrytis cinerea by the 35S∷Hrip1 lines was higher than in the rd29A∷Hrip1 lines. Moreover, stress-related gene expression in the transgenic Arabidopsis lines was significantly increased by 200 mM NaCl and 200 mM mannitol treatments, and defense genes in the jasmonic acid and ethylene signaling pathway were significantly up-regulated after Botrytis inoculation in the Hrip1 transgenic plants. Furthermore, the activity of some antioxidant enzymes, such as peroxidase and catalase increased after salt and drought stress and Botrytis infection. These results suggested that the Hrip1 protein contributes to abiotic and biotic resistance in transgenic Arabidopsis and may be used as a useful gene for resistance breeding in crops. Although the constitutive expression of Hrip1 is suitable for biotic resistance, inducible Hrip1 expression is more responsive for abiotic resistance.

Enhanced disease resistance and drought tolerance in transgenic rice plants overexpressing protein elicitors from Magnaporthe oryzae

“…The protein elicitors produced by plant pathogens can enhance resistance to pathogen infection in transgenic plants [8–10,12,13]. Rice plants expressing MoHrip1 and MoHrip2 also presented enhanced resistance against M .…”

“…With the development of genetic transformation technology, numerous examples exist of enhanced pathogen resistance through the transgenic expression of protein elicitors: The harpin-encoding gene has been expressed successfully in transgenic tobacco and rice, showing pathogen resistance [8–10]; flagellin expression induces disease resistance in transgenic rice [11]; constitutive expression of the PemG1 gene from M . oryzae in transgenic rice results in enhanced resistance to the rice blast fungus [12]; and transgenic Arabidopsis plants expressing the Hrip1 elicitor show resistance to abiotic and biotic stressors such as salt, drought, and Botrytis cinerea [13]. …”

Crystal Structure Analysis and the Identification of Distinctive Functional Regions of the Protein Elicitor Mohrip2

“…Furthermore, Several protein elicitors were reported to play functions in different plants against different diseases. For examples, Hrip1, an HR-inducing protein isolated from the fungus Alternaria tenuissima , enhances disease resistance to TMV in tobacco and to B. cinerea in Arabidopsis ( Kulye et al, 2012 ; Peng et al, 2015 ). The protein elicitor PevD1, which was isolated from the fungal pathogen Verticillium dahlia , enhances resistance to TMV in tobacco and to Verticillium wilt in cotton ( Bu et al, 2014 ; Liu et al, 2014 ).…”

Protein Elicitor PeaT1 Efficiently Controlled Barley Yellow Dwarf Virus in Wheat

“…PeaT1 (GenBank No. ABM54184.1) has been isolated from Alternaria tenuissima, triggering defense responses in various plants against fungi, viruses, aphids, salt and drought [14][15][16], and showing no direct toxicity to plant pathogenic microorganisms and aphids. In this study, we evaluated PeaT1-induced resistance in wheat against BYDV and its effects on the feeding behavior of virus transmission vector Schizaphis graminum, exploring an integrated method to control BYDV.…”