Key enzymes identified for phytoalexin synthesis

Bananas are a vital crop globally, but their yields are threatened by various diseases, including Fusarium wilt of banana caused by Fusarium oxysporum. Traditional control methods, including chemical pesticides, pose environmental risks and are not always effective.

Wild banana relatives, which have greater genetic diversity and higher concentrations of defense-related compounds, offer potential solutions. Given these challenges, further research into the genetic mechanisms behind banana disease resistance is essential.

Researchers from Jiangsu Key Laboratory for the Research and Utilization of Plant Resources and their collaborators published the study in Horticultural research.

They assembled a nearly flawless genome of Musella lasiocarpa, a wild relative of banana, to study the biosynthesis of phenylphenalenone phytoalexins (PhPN). This study identified three novel O-methyltransferases (OMTs) involved in enhancing the antifungal properties of these compounds, paving the way for the development of disease-resistant banana varieties.

The study focused on the biosynthetic pathway of PhPN phytoalexins, which are natural defense compounds in bananas. Using advanced genomic techniques, the team assembled a high-quality, near-complete genome of Musella lasiocarpa. They integrated transcriptomic and metabolomic data to identify candidate genes involved in PhPN biosynthesis.

Through phylogenetic analysis and in vitro enzymatic assays, three new OMTs were characterized. These enzymes, Ml01G0494, Ml04G2958 and Ml08G0855, played an important role in modifying PhPN methylation, thereby enhancing their antifungal activity against Fusarium oxysporum.

Ml08G0855, in particular, was found to be a multifunctional enzyme targeting multiple hydroxyl groups in PhPN structures. The study also found that methylation of PhPNs significantly increases their antifungal properties, providing a potential genetic resource to improve disease resistance of bananas through molecular breeding.

Dr Yu Chen, one of the corresponding authors, said: “This research provides crucial insights into the genetic basis of banana disease resistance. By understanding and exploiting phenylphenalenone phytoalexin biosynthetic pathways, we can develop more resilient banana cultivars, thereby ensuring better crop yields and sustainability in the face of increasing agricultural challenges.

The application of this research is twofold: it offers direct application in banana breeding programs to improve disease resistance through molecular techniques and provides a basis for further studies on the role of phytoalexins in plant interactions. -pathogens.

The implications are far-reaching and could lead to the cultivation of more resilient banana varieties that can withstand climate change-induced stress and reduce the environmental impact of disease management practices.