The ZmRCP-1 promoter of maize provides root tip specific expression of transgenes in plantain

Stephen O Onyango,Hugh Roderick,Jaindra N Tripathi,Richard Collins,Leena Tripathi,Richard O Oduor,Howard J Atkinson

doi:10.1186/s40709-016-0041-z

Abstract

BackgroundBananas and plantains (Musa spp.) provide 25 % of the food energy requirements for more than 100 million people in Africa. Plant parasitic nematodes cause severe losses to the crop due to lack of control options. The sterile nature of Musa spp. hampers conventional breeding but makes the crop suitable for genetic engineering. A constitutively expressed synthetic peptide in transgenic plantain has provided resistance against nematodes. Previous work with the peptide in potato plants indicates that targeting expression to the root tip improves the efficacy of the defence mechanism. However, a promoter that will provide root tip specific expression of transgenes in a monocot plant, such as plantain, is not currently available. Here, we report the cloning and evaluation of the maize root cap-specific protein-1 (ZmRCP-1) promoter for root tip targeted expression of transgenes that provide a defence against plant parasitic nematodes in transgenic plantain.ResultsOur findings indicate that the maize ZmRCP-1 promoter delivers expression of β-glucuronidase (gusA) gene in roots but not in leaves of transgenic plantains. In mature old roots, expression of gusA gene driven by ZmRCP-1 becomes limited to the root cap. Invasion by the nematode Radopholus similis does not modify Root Cap-specific Protein-1 promoter activity.ConclusionsRoot cap-specific protein-1 promoter from maize can provide targeted expression of transgene for nematode resistance in transgenic plantain.

Highlights

Bananas and plantains (Musa spp.) provide 25 % of the food energy requirements for more than 100 million people in Africa
We demonstrate that the Zea mays Root Cap-specific Protein-1 (ZmRCP-1) promoter provides a root tip specific activity suitable to deliver the anti-nematode defences in a monocot crop plant
Preparation and validation of plasmid constructs The construct pBI-RCP-1:GUS was prepared by cloning the ZmRCP-1 promoter and inserting the promoter fragment into the HindIII and BamHI sites of the binary vector pBI121 immediately 5′ to the β-glucuronidase gene (Fig. 1a)

Summary

Introduction

Bananas and plantains (Musa spp.) provide 25 % of the food energy requirements for more than 100 million people in Africa. One promising approach for nematode control involves transgenic expression of a non-lethal synthetic disulphide-constrained 7-mer peptide with the amino acid sequence CTTMHPRLC [8] It is taken up by nematode chemoreceptive neurons and subsequently disrupts coordinated responses to chemoreception and limits root invasion by the pathogen [9, 10]. It confers resistance in the field to a cyst nematode on potato [11] and to R. similis on plantain in a glasshouse [8] and field [12], when expressed constitutively with a cellular export signal It is Onyango et al J of Biol Res-Thessaloniki (2016) 23:4 rapidly degraded in soil and is without adverse effects on non-targeted soil nematodes [8, 11]

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