Inducible resistance to maize streak virus

Area of Science:

• Plant Virology
• Molecular Biology
• Agricultural Biotechnology

Background:

• Maize streak virus (MSV) significantly limits maize production in Africa.
• Previous MSV resistance strategies using constitutive transgenes faced limitations in plant regeneration.
• Inducible transgene expression is desirable for MSV resistance but often suffers from leaky expression.

Purpose of the Study:

• To adapt the INPACT system for inducible expression of MSV resistance genes in maize cell culture.
• To develop and test Split Gene Cassette constructs (SGCs) for MSV-inducible transgene expression.
• To evaluate the efficacy of SGCs in inhibiting MSV replication.

Main Methods:

• Development of SGCs combining transgenes with specific promoter sequences for MSV-dependent translation.
• Utilizing a quantitative real-time PCR assay to measure MSV replication inhibition.
• Testing SGC efficacy in maize cell culture against various MSV strains and related mastreviruses.

Main Results:

• One SGC, pSPLITrepIII-Rb-Ubi, demonstrated inducible inhibition of MSV replication comparable to constitutive transgenes.
• The developed SGC system effectively inhibited replication of diverse MSV strains in cell culture.
• The SGC system showed cross-activity against a different mastrevirus species, albeit to a lesser extent.

Conclusions:

• The adapted INPACT system using SGCs provides an effective inducible transgene expression strategy for MSV resistance.
• This technology offers a potentially improved and more acceptable approach for developing MSV-resistant maize.
• The inducible nature of this system could overcome limitations associated with constitutive expression in transgenic crops.