b'ON THE ROCKYwestern shores of theThe kicker? It only takes four amino acid substi-Galpagos Islands, wild tomatoes are doingtutions in that enzyme to flip the chemical signa-something evolutionary theory once consid- ture from modern to ancestral.ered nearly impossible: theyre going backward.The fact that just four amino acid changes in Scientists call it a rare case of reverse evolution,the GAME8 enzyme can flip the stereochemistry of but what matters most to the future of agriculturethese compounds shows how precise and targeted is the chemistry behind the changeand whatthis kind of trait manipulation could be, Jozwiak it could mean for breeders, seed companies andsays. In theory, we could use CRISPR gene edit-Reveals a Hiddenfarmers trying to build more resilient crops. ing to introduce specific mutations that shift the At the center of this breakthrough is Solanumchemical profiles.cheesmaniae, a wild tomato species native to theHis team didnt stop at tomatoes. They intro-archipelago. On newer islands formed by volcanicduced the modified GAME8 gene into tobacco Defense in Tomatoes activity, this plant has developed a molecularplants, which then produced the same ancestral profile that closely resembles its ancient ances- alkaloids. It was a rare, clear demonstration that tors. According to University of California-Riversideevolution doesnt always move in one direction, assistant professor of molecular biochemistryand that reversing a major plant chemistry path-Adam Jozwiak, its not just an oddity, its a poten- way is both possible and predictable.tial roadmap for strengthening tomato defenses in an era of mounting pest pressure and reducedA New Frontier for Crop Defensepesticide use. That level of biochemical control opens the door for what Jozwiak calls designer plant chemistry, Unlocking Ancestral Chemistry where breeders and biotech firms could tailor Commercial tomato varieties could easily bealkaloid profiles to balance pest resistance, flavor, screened for the presence of both stereoiso- safety and shelf life.meric forms of steroidal glycoalkaloids usingIf the goal were to make plants more resist-standard metabolite profiling techniques such asant to pests, then a logical approach would be to LC-MS, Jozwiak explains. Thats straightforward.upregulate key biosynthetic enzymes, particularly However, detecting whether a variety is primed toGAME8, GAME6 and GAME15, he says. But do revert to ancestral chemistry is a different story. so in a tissue-specific or developmental-stage-And that story is complicated. Tomatoes, likespecific way.many crops in the Solanaceae family, produce ste- For example, boosting SGAs in leaves and roidal glycoalkaloids (SGAs)bitter-tasting, toxicstems (the parts of the plant that arent consumed) compounds that protect the plant from insects,could increase pest deterrence without compro-fungi and pathogens. In modern breeding, thosemising fruit quality. Alternatively, delaying the compounds have been systematically reducednatural conversion of -tomatine (a bitter, toxic in ripe fruit to satisfy consumer preferences forcompound) into its non-toxic form, esculeoside A, sweeter, milder tomatoes. might allow for better protection during early fruit Tomato breeders have worked to reduce bit- development while preserving taste at harvest.terness in cultivated varieties for decades, JozwiakAnother approach could involve fine-tuning the says. But by reducing these compounds for thetiming of alkaloid conversion during ripening, to sake of flavor, we may have unintentionally com- maximize pest resistance early in fruit development promised the plants natural immune system. while ensuring a palatable product at harvest, Jozwiak explains.The Four-Amino-Acid SwitchThats where the Galpagos tomatoes come in.Balancing Flavor and FunctionOn newer islands like Fernandina and Isabela, S.But any strategy involving increased SGAs would cheesmaniae plants produce alkaloids with a ste- need careful testing and regulatory scrutiny. These reochemistry not seen in cultivated tomatoes forcompounds, while natural, can be toxic to humans millions of years. These compounds resemble theand animals at high doses. In modern tomatoes, bitter, bioactive chemicals found in eggplants, andtheyre typically present in unripe fruit and veg-theyre synthesized through an altered version ofetative tissuebut the ripe fruit contains little to the GAME8 enzyme. none.FEBRUARY 2026SEEDWORLD.COM /25'