Virus-mediated, heritable gene editing in groundcherry (Physalis grisea)

Area of Science:

• Plant Biotechnology
• Genomics
• Crop Science

Background:

• Conventional plant genome engineering often requires extensive tissue culture.
• Virus-induced gene editing (VIGE) offers an alternative for in planta genome modification.
• Groundcherry (Physalis grisea) is an underutilized crop with potential for genetic improvement.

Purpose of the Study:

• To establish Tobacco rattle virus (TRV)-mediated VIGE as an efficient genome editing system in groundcherry.
• To evaluate the efficiency of VIGE for both somatic and heritable genome editing in groundcherry.
• To assess the potential of VIGE for accelerating the genetic improvement and de novo domestication of groundcherry.

Main Methods:

• TRV-mediated delivery of guide RNAs into Cas9-expressing groundcherry plants.
• Targeting of the PHYTOENE DESATURASE (PDS) gene for visual assessment of editing.
• Targeting of the CLAVATA1 (CLV1) gene to evaluate effects on domestication traits.
• Evaluation of editing efficiencies in somatic tissues and across progeny to determine heritability.

Main Results:

• High somatic editing frequencies (80-95%) for the PDS gene and consistent recovery of heritable edits.
• Successful generation of mono-, bi-, tri-, and tetra-allelic mutations in a tetraploid Cas9-expressing line.
• Somatic editing frequencies of up to 73% for the CLV1 gene, with 60% of T0 plants yielding heritable edits.
• Observed CLV1 loss-of-function phenotypes, including increased floral organ number and multilocular fruits.

Conclusions:

• VIGE is a rapid, efficient, and heritable genome editing tool for groundcherry, adaptable to tetraploid contexts.
• This VIGE system holds significant potential for accelerating genetic improvement and de novo domestication of underutilized crops.
• TRV-mediated VIGE provides a valuable alternative to traditional methods, bypassing the need for extensive tissue culture.