Enhanced tolerance to Phytophthora root and stem rot by over-expression of the plant antimicrobial peptide CaAMP1 gene in soybean

Lu Niu,Rui Ma,Yingshan Dong,Dongbo Liu,Haiyun Li,Yuanyu Zhang,Xiangdong Yang,Jing Yang,Xiaofang Zhong,Guojie Xing

doi:10.1186/s12863-020-00872-0

Abstract

BackgroundAntimicrobial peptides play important roles in both plant and animal defense systems. Moreover, over-expression of CaAMP1 (Capsicum annuum antimicrobial protein 1), an antimicrobial protein gene isolated from C. annuum leaves infected with Xanthomonas campestris pv. vesicatoria, confers broad-spectrum resistance to hemibiotrophic bacterial and necrotrophic fungal pathogens in Arabidopsis. Phytophthora root and stem rot (PRR), caused by the fungus Phytophthora sojae, is one of the most devastating diseases affecting soybean (Glycine max) production worldwide.ResultsIn this study, CaAMP1 was transformed into soybean by Agrobacterium-mediated genetic transformation. Integration of the foreign gene in the genome of transgenic soybean plants and its expression at the translation level were verified by Southern and western blot analyses, respectively. CaAMP1 over-expression (CaAMP1-OX) lines inoculated with P. sojae race 1 exhibited enhanced and stable PRR tolerance through T2–T4 generations compared with the wild-type Williams 82 plants. Gene expression analyses in the transgenic plants revealed that the expression of salicylic acid-dependent, jasmonic acid-dependent, and plant disease resistance genes (R-genes) were significantly up-regulated after P. sojae inoculation.ConclusionsThese results indicate that CaAMP1 over-expression can significantly enhance PRR tolerance in soybean by eliciting resistance responses mediated by multiple defense signaling pathways. This provides an alternative approach for developing soybean varieties with improved tolerance against soil-borne pathogenic PRR.

Highlights

Antimicrobial peptides play important roles in both plant and animal defense systems
We found that over-expression of Capsicum annuum antimicrobial protein 1 (CaAMP1) enhanced soybean tolerance to Phytophthora root and stem rot (PRR), and induced the expression of genes involved in salicylic acid (SA)- and JAdependent pathways and resistance genes (R-genes) signaling
The Polymerase chain reaction (PCR) confirmed that T3 transgenic soybean lines contained CaAMP1 and bar genes (Fig. 1c)

Summary

Introduction

Antimicrobial peptides play important roles in both plant and animal defense systems. Vesicatoria, confers broad-spectrum resistance to hemibiotrophic bacterial and necrotrophic fungal pathogens in Arabidopsis. Over-expression of CaAMP1 enhances tolerance to hemibiotrophic bacterial and necrotrophic fungal pathogens in Arabidopsis, when compared with the wild-type plants, and induces two salicylic acid (SA) pathway-dependent genes, i.e., PR1 (PATHOGENESIS-RELATED) and PR5 expression [8]. Leaf extracts from transplastomic tobacco are shown to inhibit the growth of pregerminated spores of three fungal species, Aspergillus flavus, F. moniliforme, and Verticillium dahliae [3], whereas expression of the AMP alfAFP in transgenic greenhouse-grown potato confers tolerance against V. dahliae, an agronomically important fungal pathogen [11]. AMPs have been demonstrated to enhance tolerance to fungal diseases in bentgrass and citrus [12, 13] These findings evidence that AMPs play key roles in plant defense against fungal pathogens, and that over-expression of these peptides can enhance tolerance against many fungal diseases

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Discussion

Conclusion