GPM1 Strengthens Early Graft Adhesion Across Legume Crops

Aug 04, 2026

A newly identified small molecule could help grafted plants establish a stronger first connection, potentially expanding grafting in crops that are difficult to join. By screening 3,000 synthetic compounds, researchers discovered graft-promoting molecule 1 (GPM1), which increased early tissue adhesion in several legume species and in a cross-species graft combination. The compound also improved graft performance in two plants outside the legume family. Molecular and anatomical evidence indicates that GPM1 promotes cell-wall remodeling and callus-cell expansion at the cut surface without triggering the broad auxin response seen with conventional hormone treatment. The findings introduce a targeted chemical strategy for making early graft healing more reliable.

Grafting joins a shoot, or scion, to a rootstock so growers can combine useful traits such as disease resistance, stress tolerance, productivity, and quality. Success, however, depends on a tightly timed healing sequence: cut surfaces must adhere, callus tissue must bridge the wound, and vascular connections must be restored. These steps can be unreliable in Fabaceae, the major crop family that includes soybean, cowpea, common bean, pea, lentil, chickpea, and alfalfa. Weak adhesion at the earliest stage can leave gaps or damaged layers that disrupt later tissue reunion, even between related species. Based on these challenges, there is a need to identify practical regulators that strengthen early graft adhesion in Fabaceae crops.

Researchers from Nagoya University, Kyoto University, and Huazhong Agricultural University published (DOI: 10.1093/hr/uhag095) the study in Horticulture Research on 13 March 2026. Using a high-throughput in vitro grafting (IVG) platform, the team screened a 3,000-compound library and identified graft-promoting molecule 1 (GPM1) as a graft-promoting molecule. They then evaluated its effects across four Fabaceae species, a cowpea–soybean heterograft, and two non-legume models, combining mechanical-force measurements, RNA sequencing (RNA-seq), quantitative reverse transcription polymerase chain reaction (qRT-PCR), root-response assays, and histological imaging to determine how the compound supports early graft union formation.

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Video: Western Canadian Agriculture: Hard Times Made the World's Best Farmers

Western Canadian agriculture produced the most advanced farmers in the world not through abundance but through adversity. The crow rate fell. The wheat price went nowhere. The brown envelopes stopped.

When the subsidies disappeared, the bad farmers left and the good ones stayed. And the ones who stayed could not just grow wheat anymore. They started growing lentils and canola and peas and flax and faba beans. They built crop rotation. They got serious about agronomy because there was no government backstop. That process produced the Western Canadian agriculture Dennis Bulani describes in this clip: the most advanced, most educated farming culture in the world.

His contrast with Iowa corn and soybean farmers is sharp. At a DeKalb farmer meeting in Okoboji, Iowa, he asked what crop rotation they ran. Beans on corn stubble, corn on bean stubble. How do you fertilize? The co-op agronomist handles it. Have you considered other crops? No need. We make so much money on corn and soybeans. Western Canadian agriculture was never allowed that comfort. And now those Iowa farmers are watching soybean markets lock up with China and corn prices slide, and they do not have the agronomy knowledge or the research base to pivot. Western Canadian farmers adapted on a dime because they had done it before.

Dennis also makes the case that Western Canadian agriculture keeps adapting in real time. Low commodity prices over the past year have pushed growers to look seriously at precision spot-spray technology. He knows a neighbor who bought a sprayer with the seeing-eye system and sprayed only 80 out of 320 acres. As a chemical retailer Dennis acknowledges that will affect his sales. He supports it anyway, because if it advances Canadian agriculture and makes farmers money, that is a good outcome.

The lesson Dennis draws from the tale of two farms: continuous improvement is the only durable strategy. When canola was $22 a bushel some growers went to Arizona instead of the Crop Production Show. When the price came down those same growers came back to the research and the discipline. Products do not go on Rack Petroleum's shelves unless they pass a replicated trial first. That is what Western Canadian agriculture built through hard times: farmers who do the work whether the times demand it or not.

Dennis Bulani is CEO of Rack Petroleum and Ultimate Yield in Biggar, Saskatchewan. Dan Aberhart hosts GTF Productions, Western Canadian Agriculture's foremost live briefing platform and its foremost AI training platform for ag operators