Jatropha curcas, a perennial woody plant species in the Euphorbiaceae family. This drought-resistant shrub is widely recognized for its potential to produce biodiesel and bio-jet fuel on marginal lands, avoiding competition with food production. However, its naturally low seed production has limited commercial use.

In a study published in Plant Biotechnology Journal, researchers from Xishuangbanna Tropical Botanical Garden (XTBG) of the Chinese Academy of Sciences have identified a key gene that can significantly increase both seed yield and oil content in Jatropha.

The research focused on plant development genetics and highlighted the important role of a gene called JcSPL9, which belongs to the squamosa promoter binding protein-like (SPL) family. This gene acted as a master switch, controlling when the plant shifted from growing leaves to producing flowers and seeds.

Experiments showed that plants engineered to overexpress a modified form of JcSPL9 (called rJcSPL9) produced 80.76% more seeds and had 12.6% higher oil content compared to normal plants. In contrast, boosting a related molecule called JcmiR156a led to a 51.67% drop in seed yield and an 8.28% decrease in oil content.

Further analysis revealed that rJcSPL9 turns on genes involved in oil production, while JcmiR156a turns them off. This confirms that JcSPL9 enhances oil accumulation by regulating metabolic pathways.

The study also found changes in the types of fatty acids produced in the seeds, indicating that this genetic mechanism broadly affects oil composition.

“We demonstrate, for the first time, that SPL9 plays an important role in regulating fatty acid biosynthesis and lipid accumulation in seeds, by using the rJcSPL9 and JcmiR156a transgenic Jatropha,” said TANG Mingyong of XTBG.

The dual effect on both yield (quantity) and oil content (quality) makes SPL9 an exceptionally promising target for molecular breeding. “The strategy of using a miR156-resistant SPL9 gene could be applied to other crucial oilseed crops, such as soybean, canola, and sunflower, to sustainably meet the growing global demand for biofuels and renewable resources,” said TANG.

Jatropha curcas (Image by TANG Mingyong）

Jatropha curcas (Image by TANG Mingyong）

First published: 23 January 2026