Improving cassava bacterial blight resistance by editing the epigenome

Area of Science:

• Plant pathology
• Epigenetics
• Molecular biology

Background:

• Pathogen infection relies on host susceptibility (S) genes.
• DNA methylation is an epigenetic mechanism regulating gene expression.
• Targeted methylation of S genes offers a potential strategy for enhancing crop disease resistance.

Purpose of the Study:

• To investigate the potential of epigenome editing for crop improvement.
• To block the induction of the MeSWEET10a susceptibility gene by Xanthomonas phaseoli pv. manihotis TAL20 effector.
• To develop a novel approach for enhancing disease resistance in cassava.

Main Methods:

• Utilized a synthetic zinc-finger DNA binding domain fused to an RNA-directed DNA methylation component.
• Directed targeted DNA methylation to the TAL20 effector binding element in the MeSWEET10a promoter.
• Assessed the impact of methylation on TAL20 binding, MeSWEET10a expression, and cassava bacterial blight (CBB) symptoms in vivo.

Main Results:

• Successfully directed methylation to the target DNA element.
• Demonstrated that methylation prevents TAL20 binding and blocks MeSWEET10a transcriptional activation.
• Observed decreased CBB symptoms in edited plants with no adverse effects on normal growth and development.

Conclusions:

• Epigenome editing via targeted DNA methylation is a viable strategy for crop improvement.
• This approach can effectively confer disease resistance by blocking pathogen-induced susceptibility gene expression.
• The developed method offers a promising tool for enhancing agricultural resilience against pathogens.