Colorado State University researchers found that restoring cytokinin signaling in immune-activated Arabidopsis thaliana improved growth and reproductive output without weakening disease resistance.The treated or genetically altered plants also became more resistant to pathogens with different lifestyles, suggesting that the long-recognized tradeoff between plant growth and defense can sometimes be partially uncoupled.The work remains limited to a laboratory model plant, but it points toward hormone crosstalk as a possible route for developing crops that maintain yield while defending themselves against disease.<\/p>\n
Plants face a hard choice whenever disease strikes. They can defend themselves, or they can keep growing at full strength. A new study from Colorado State University<\/a> suggests that choice may not always need to be so painful.<\/p>\n Researchers found a way to boost plant growth while keeping immunity strong in Arabidopsis thaliana, a small mustard-family plant widely used in biology research. The findings could one day help scientists design crops that resist disease without losing yield.<\/p>\n The work focuses on plant hormones, the chemical signals that help plants respond to stress, pests and changing conditions. By adjusting one hormone pathway, the team helped immune-activated plants grow better and defend themselves more effectively.<\/p>\n The Cost of Plant Defense<\/p>\n Plants have immune systems<\/a>, much like people do. They can sense threats such as disease-causing microbes and activate defenses that help them survive.<\/p>\n Colorado State University researchers Grace Johnston, left, and Professor Cris Argueso have found a way to boost a plant\u2019s growth while maintaining its immunity through a hormone treatment that shows promise for food production. (CREDIT: Colorado State University) <\/p>\n But those defenses come with a cost. When immunity turns on, growth often slows. For a wild plant, that tradeoff may help it survive. For a food crop, it can mean smaller harvests.<\/p>\n A plant facing disease produces chemical signals that protect it from harm. At the same time, those signals can suppress the growth needed for leaves, seeds and yield.<\/p>\n This long-standing problem is known as the growth-defense tradeoff. Farmers need plants that can resist pathogens<\/a>, but they also need plants that remain productive.<\/p>\n A Possible \u201cGreen\u201d Green Revolution<\/p>\n The CSU team sees this work as a possible step toward more secure food production. If crops can defend themselves without major yield loss, farmers may need fewer chemical inputs.<\/p>\n \u201cOnly time will tell once it\u2019s integrated into crops what effect this will have, but it does have the potential to be as big of a breakthrough as the Green Revolution 60 years ago in terms of food security,\u201d said Cris Argueso, an associate professor in CSU\u2019s Department of Agricultural Biology and senior author of the study.<\/p>\n The Green Revolution<\/a> changed global agriculture after Norman Borlaug developed high-yield wheat varieties. Those crops helped prevent famine and earned Borlaug a Nobel Peace Prize.<\/p>\n But that revolution also brought heavy use of fertilizers and pesticides. Argueso hopes this approach could support a cleaner version.<\/p>\n \u201cWe want to create crop plants that can defend really well against pathogens but don\u2019t have a yield penalty, which is the dream for farmers,\u201d Argueso said. \u201cWe joke that this is the \u2018green\u2019 Green Revolution.\u201d<\/p>\n Plants have an immune system that is triggered when they are stressed; this immune response also stunts the plant’s growth. Scientists have found a way to turn plant growth back on. (CREDIT: Colorado State University) The Plant\u2019s Chemical Brain<\/p>\n Argueso calls plant hormones the plant\u2019s \u201cchemical brain.\u201d These signals help plants interpret the world around them and decide how to respond.<\/p>\n One key hormone group is cytokinins. These hormones help control cell division, plant development and growth. They also play roles in stress responses and nutrient signaling.<\/p>\n When plants face pests or disease, cytokinin signaling can drop. That helps explain why immune activation often comes with weaker growth.<\/p>\n The researchers studied Arabidopsis thaliana plants with an autoimmune mutation<\/a>. These plants behave as if their immune systems stay switched on.<\/p>\n That makes them useful for science. They show what happens when defense stays active, even without a real infection.<\/p>\n Restoring a Growth Signal<\/p>\n In these autoimmune plants, the team found that constant immune activation suppressed cytokinin signaling. That suppression harmed growth and productivity.<\/p>\n The scientists then restored cytokinin levels. This changed the plant\u2019s internal hormone balance<\/a> and restarted growth without weakening defenses.<\/p>\n In fact, the engineered plants became even more resistant to disease. That result matters because it challenges the idea that growth and defense must always work against each other.<\/p>\n In these autoimmune plants, the team found that constant immune activation suppressed cytokinin signaling. (CREDIT: Shutterstock) <\/p>\n The plants improved through changes in meristem activity. Meristems are growth zones where plant cells divide and produce new tissues.<\/p>\n Healthy meristems help plants make leaves, flowers and seeds. By restoring cytokinin signaling, the researchers helped those growth centers keep working.<\/p>\n Fighting Different Kinds of Disease<\/p>\n The study found benefits against pathogens with different lifestyles. Some pathogens feed on living plant tissue. Others kill plant tissue and feed on the dead material.<\/p>\n Plants usually use different defense strategies against these threats. Helping defend against both types is especially valuable.<\/p>\n That suggests the hormone adjustment did not simply trade one defense pathway for another. Instead, it helped the plant maintain broad immunity while reducing the growth penalty.<\/p>\n The work also involved other hormone pathways, including salicylic acid<\/a> and jasmonic acid. These signals help plants respond to different kinds of attack.<\/p>\n The key idea is hormone crosstalk. Plant hormones communicate with each other, and that communication shapes growth, immunity and survival.<\/p>\n A Faster Route Than Gene Hunting<\/p>\n Traditional crop improvement often requires researchers to find specific genes tied to desired traits. That process can take years and may involve mapping large parts of the genome.<\/p>\n Argueso said their approach may offer a simpler route. Instead of hunting for one responsible gene, the team adjusted the plant\u2019s chemical signaling balance.<\/p>\n She compares the idea to how a doctor might prescribe a pill to correct a chemical imbalance<\/a>. In plants, the goal is to restore a signal that defense had suppressed.<\/p>\n The approach still involves genetic manipulation in the study. But the target is a broad hormone response, not one narrow trait gene.<\/p>\n Argueso expects the mutations developed by her team could remain useful in agriculture for decades.<\/p>\n \u201cWe are exploring collaborations with breeding programs across the world, so this can be tested in different regions with all sorts of crops,\u201d Argueso said. \u201cIf these mutations have the potential that we think they do, we would like them to be used everywhere.\u201d<\/p>\n From Lab Plant To Food Crops<\/p>\n