🌱 New insights into cassava root development 🌱

We are proud to share the successful completion of a PhD thesis within our CASS consortium. This work provides important insights into cassava physiology and root development – a key step towards understanding how to unlock the crop’s full potential for food security and resilience.

"The goal of my PhD thesis was to analyze one of the more important aspects of cassava physiology: the development of the storage root. We were able to show that the cassava storage root is formed from primary fibrous roots through the activity of a single vascular cambium that first produces wood and later large amounts of starch-filled storage parenchyma, which causes the root to visually bulk. This transition in anatomy is accompanied by a switch in the storage root transcriptome from secondary cell wall to starch metabolism. Not only that, but we also observed an increase in the expression of transporter encoding genes related to sugar accumulation in the vacuole. This coincided with an increase of sucrose and hexoses in storage roots upon root bulking and specifically in vacuoles. While this accumulation could be used for beneficially by the plant by causing increased sink strength, cell swelling and drought tolerance, there is ample evidence that high amounts of sugars and other metabolites are correlated with decreased starch content, making sub-cellular compartmentalization of sugars an interesting avenue for improvement. On the other side of the source-sink spectrum, a lack of expression of sucrose transporting SWEET-III genes, the presence of branched plasmodesmata in the companion cell/bundle sheath interface and high leaf sucrose concentration were evidence for a predominantly passive symplasmic phloem loading strategy in cassava source leaves. Lastly, we exploited the anatomical similarity of the stem and storage roots to study the transcriptome of two vascular cambia that produce wood and storage parenchyma, respectively. This revealed a general repression of positive regulators of secondary cell wall formation in the developing xylem of the storage organ. Furthermore, changes in expression of major vascular cambium regulators like BP/KNAT1 or WOX14 were observed, which could directly influence secondary cell wall formation.

I am glad that through my own perseverance as well as the support of many of my friends and colleagues I could finish a PhD thesis that I can be proud of. I sincerely hope that the generated data as well as the derived hypotheses will be useful for future cassava research and that others will build upon what I could find out. Lastly, I would like to thank everyone involved, including my co-authors, collaborators and the whole consortium, but especially Dr. Wolfgang Zierer for the support and supervision. I could not have done it alone."

👏 Congratulations on this achievement – and thank you for your contribution to advancing cassava research!

#Cassava #PlantScience #FoodSecurity #CASSproject #PhDResearch