INFORM October 2025

18 • inform October 2025, Vol. 36 (9)

Genes of intrest

Selectable marker

Harvested seeds screened for selectable markers

T-DNA

Dipped plants covered overnight to maintain high humidity

Flowers dipped in Agrobacterium suspension

Transgenic seeds (DsRed+) under green light and red lense filter

Vir genes

Agrobacterium Tumefaciens

Wildtype seeds under green light and red lense filter

Vacuum applied to enhance infiltration of Agrobacterium

Plants transferred to growth chambers for recovery and seed maturation

Camelina at early flowering stage

Agrobacterium suspension

Agrobacterium -mediated transformation of Camelina and Pennycress Most plant species are difficult to genetically transform, often requiring laborious tissue culture to regenerate plants from transformed cells. An important exception is the model plant Arabidopsis thaliana , which can be effi ciently transformed through Agrobacterium -mediated flo ral dip, bypassing tissue culture entirely. This approach has been extended to two emerging oilseed crops, Camelina sativa and Thlaspi arvense (field pennycress), making them useful platforms for plant biotechnology. Agrobacterium tumefaciens is a soil bacterium that developing flowers in an Agrobacterium suspension con taining a surfactant to reduce surface tension. A key part of the protocol involves using vacuum infiltration to draw the bacterial suspension deeper into floral tissues, increasing access to target cells. Following infiltration, plants are maintained under high humidity to support infection. Seeds are harvested from treated plants, and transgenic progeny are identified via reporter genes such as DsRed or selectable markers such as herbicide resistance.

they can easily be genetically modified using Agrobacterium mediated floral dip transformation with vacuum infiltration (see sidebar). Agronomically, both crops fit well into existing agricultural systems. They grow in the off-season between major food crops, tolerate diverse environmental conditions, and require minimal water and fertilizer. Compared to other oilseed crops such as soybean, they have short growing cycles and a relatively high oil yield. As cover crops, they naturally transfers a segment of its plasmid DNA (T-DNA) into plant cells during infection. This DNA integrates into the plant genome, enabling stable expression of intro duced genes. Researchers have taken advantage of this ability, replacing the bacterium’s tumor-inducing genes with desired transgenes, thus harnessing Agrobacterium ’s natural DNA delivery machinery for crop improvement. For camelina and pennycress, the method involves growing plants until early flowering, then immersing

suppress weeds, reduce erosion, and retain nutrients, contributing to soil health. BUILDING THE PATHWAY Our work involved multiple metabolic engineering strategies, with the goal of matching the acetyl-TAG levels found in some Euonymus seeds—over 90 mol percent. To reach these levels, we first needed to build the acetyl-TAG biosynthetic pathway in camelina and pennycress. Using this method, transformation efficiencies reach about one percent in camelina and half a percent in pen nycress. These protocols allow simple, tissue-culture-free introduction of diverse traits, including altered fatty acid composition and increased oil content. They can also be applied to implement genome editing in camelina and pennycress, enabling precise mutation of genes of inter est. Together, these advances accelerate the agronomic improvement of these oilseeds.