Perez-Fons, L. | Search bioRxiv

bioRxiv2023

The FIBRILLIN multigene family in tomato, their roles in plastoglobuli structure and metabolism

Plastoglobuli (PG) are plant lipoprotein compartments, present in plastid organelles. They are involved in the formation and/or storage of lipophilic metabolites. FIBRILLINs (FBN) are one of the main PG-associated proteins and are particularly abundant in carotenoid-enriched chromoplasts found in ripe fruits and flowers. To address the contribution of different FBNs to isoprenoid sequestration and PG function, a multiplex gene editing approach was undertaken. Analysis of single and high-order fbn mutants for the major PG-related FBNs in tomato, namely SlFBN1, SlFBN2a, SlFBN4, SlFBN7a, revealed functional redundancy. High order fbn mutants displayed phenotypes associated with abnormal isoprenoid accumulation, and aberrant PG formation and morphology. Lipidomic analysis highlighted broader changes in lipid metabolism. Paralog-specific roles were also observed and included the regulation of specific isoprenoids (e.g., plastochromanol) and control of plastidial esterification capability by SlFBN7a. Collectively, the results support both structural and regulatory roles of SlFBNs in PGs. Our findings expose fundamental aspects of metabolic compartmentalisation in plant cells and the importance of lipoprotein particles for their plastid metabolism/physiology. Significance statementIn the chromoplast of ripe tomato fruit and flower, plastoglobuli (PGs) are associated with several important biotechnological traits, due to their functional involvement in metabolism, developmental transitions, and environmental adaption. FIBRILLINS (FBN) are a multigene family of proteins that are collectively major components of the PG. Using a multiplex CRISPR-Cas9 approach single and high-order fbn mutants have been developed. Functional redundancy amongst the members of the FBN multigene family was evident, but also paralog specific functions/influence. Aberrant plastoglobuli formation and altered lipid metabolism are evident among fbn mutants. Characterisation of this resource has shed light on the functional role of FBN and their role in PG formation. This strategy offers new potential for the development of nutritional enhanced and climate resilient crops.

plant biology↗

bioRxiv2022

Integrated genetic and metabolic characterisation of diverse Latin American cassava (Manihot esculenta Crantz) germplasm; implications for future breeding strategies

Cassava is an important staple crop for food security in Africa and South America. The present study describes an integrated genomic and metabolomic approach to the characterisation of Latin American cassava germplasm. Classification based on genotyping and the leaf metabolome correlates, the key finding being the adaption to specific eco-geographical environments. In contrast the root metabolome does not relate to the genotypic clustering, suggesting different spatial regulation of this tissues metabolome. The data has been used to generate pan-metabolomes for specific tissues and the inclusion of phenotypic data has enabled the identification of metabolic sectors underlying traits of interest. For example, tolerance to whiteflies was not linked to cyanide content but to cell wall related phenylpropanoids or apocarotenoids. Collectively, these data advance the communities resources and provides a valuable insight into new parental breeding materials with traits of interest directly related to combating food security. Significance statementCassava is a staple crop in developing countries of sub-tropical regions. Traditionally, cassava has been considered as a subsistence crop. However recently it has become a sustainable solution to fulfil both hunger and malnutrition needs, and drive economic development. Varietal improvement via classic breeding has successfully delivered products into the Asian market by including/exchanging germplasm from original Latin American collections. Conversely, modest progress has been achieved in Sub-Saharan countries since genetic resources are biased towards exploitation of local landraces and uncharacterised parental material. The present work explores the genetic and metabolic diversity of Latin American cassavas genebank, one of the largest and most complete worldwide. These data provide a robust characterisation of valuable germplasm that can be exploited in breeding programmes.

plant biology↗