Maize lethal necrosis and the molecular basis of variability in concentrations of the causal viruses in co-infected maize plant.

A O Awata L,W Marchelo-D’Ragga P,Sitonik Chelang’At,B Jumbo M,Danquah E,E Ifie B,Tongoona P,Gowda M,M Suresh L

doi:10.5897/jgmv2019.0073

Abstract

Maize lethal necrosis (MLN) disease is new to Africa. First report was in Kenya in 2012, since then the disease has rapidly spread to most parts of eastern and central Africa region including Tanzania, Burundi, DRC Congo, Rwanda, Uganda, Ethiopia and similar symptoms were observed in South Sudan. Elsewhere, the disease was caused by infection of Maize Chlorotic Mottle Virus (MCMV) in combination with any of the potyviruses namely; maize dwarf mosaic virus (MDMV), sugarcane mosaic virus (SCMV) and tritimovirus wheat streak mosaic virus (WSMV). In Africa, the disease occurs due to combined infections of maize by MCMV and SCMV, leading to severe yield losses. Efforts to address the disease spread have been ongoing. Serological techniques including enzyme-linked immuno-sorbent assay (ELISA), polymerase chain reaction (PCR), genome-wide association (GWAS) mapping and next generation sequencing have been effectively used to detect and characterize MLN causative pathogens. Various management strategies have been adapted to control MLN including use of resistant varieties, phytosanitary measures and better cultural practices. This review looks at the current knowledge on MLN causative viruses, genetic architecture and molecular basis underlying their synergistic interactions. Lastly, some research gaps towards MLN management will be identified. The information gathered may be useful for developing strategies towards future MLN management and maize improvement in Africa.

Highlights

Maize (Zea mays L., 2n=2x=20) is a major staple food and source of income and livelihood for the majority of smallholder farming communities in sub-Saharan Africa (Sharma and Misra, 2011; Ranum et al, 2014)
Serological techniques including enzyme-linked immuno-sorbent assay (ELISA), polymerase chain reaction (PCR), genome-wide association (GWAS) mapping and generation sequencing have been effectively used for detection and characterization of the maize lethal necrosis (MLN) causative pathogens
Various serological methods such as enzymelinked immunosorbent assay (ELISA), the Reverse-Transcription Polymerase Chain Reaction (RT-PCR) that amplifies the small quantity of nucleic acid, generation sequence (NGS) and northern blots have been adapted for study and identification of the cause of MLN (Shukla et al, 1989; Mezzalama, 2015; Thorat et al, 2015)

Summary

INTRODUCTION

Maize (Zea mays L., 2n=2x=20) is a major staple food and source of income and livelihood for the majority of smallholder farming communities in sub-Saharan Africa (Sharma and Misra, 2011; Ranum et al, 2014). They can feed on SCMV infected maize plant for an acquisition access period of about 20-30 s and transmit the virus into a healthy plant in a non-persistent (styletborne transmission) manner within 1-2 min inoculation access period (Sharma and Misra, 2011). The present methods of detecting plant viruses involve primarily the transmission of the virus from a diseased to a healthy plant This can be done through rubbing leaves of healthy plants with sap from an infected plant or insect vectors and confirmed by purification, electron microscopy, and, most commonly, serology (Adams et al, 2013; Mezzalama, 2015; Xie et al, 2016).

Serological methods

Findings

CONCLUSION