BEGIN:VCALENDAR VERSION:2.0 PRODID:-//CERN//INDICO//EN BEGIN:VEVENT SUMMARY:Investigating the secondary loss of auxin signalling components in duckweed DTSTART;VALUE=DATE-TIME:20260929T144500Z DTEND;VALUE=DATE-TIME:20260929T150000Z DTSTAMP;VALUE=DATE-TIME:20260921T233455Z UID:indico-contribution-431-2904@cern.ch DESCRIPTION:Speakers: Claire Smith (Plant and Crop Sciences\, School of Bi osciences\, University of Nottingham)\nEvolutionary studies mainly focus o n the acquisition of new traits in highly diversified plant lineages\, wit h comparatively few studies showing how these traits have undergone second ary loss. Duckweeds provide a tractable system to address this within angi osperms\, as they have gradually lost the ability to grow roots and vascul ature. These lost traits are regulated by auxin in other angiosperms. The core auxin signalling network relies on three key protein families: AUXIN RESPONSE FACTORS (ARFs)\, AUXIN/INDOLE-3 ACETIC ACIDS (AUX/IAAs)\, and TRA NSPORT INHIBITOR 1/AUXIN SIGNALLING F-BOX (TIR1/AFBs). During the evolutio n of land plants there have been expansions in the number of network compo nents\, creating a diverse network with high specificity of response. Ther e have been many studies on how this network has evolved from algae to ang iosperms\, but no research how components have been lost secondarily. We f ound that there has been a reduction in the number of components across al l duckweeds\, however most subclades have been conserved\, and that a wide panel of duckweeds respond to exogenous auxin in growth assays. We found that the rootless *Wolffia australiana* responds transcriptionally to auxi n\, although the genes that are induced are distinct from those induced in rooted duckweeds. This work shows a correlation between the loss of struc tural complexity and reduction of the auxin signalling network\, which is the opposite of what is observed during the evolution of angiosperms. This positions duckweeds as a good model for research into secondary loss and provides a minimal system with low levels of genetic redundancy.\n\nhttps: //indico.unina.it/event/117/contributions/2904/ LOCATION:Department of Agricultural Sciences of the University of Napoli F ederico II\, Portici\, Italy Sala Cinese URL:https://indico.unina.it/event/117/contributions/2904/ END:VEVENT BEGIN:VEVENT SUMMARY:On the Way to Domesticate Duckweeds: Hidden Sexuality\, Hybridizat ion and Polyploid Evolution DTSTART;VALUE=DATE-TIME:20260929T143000Z DTEND;VALUE=DATE-TIME:20260929T144500Z DTSTAMP;VALUE=DATE-TIME:20260921T233455Z UID:indico-contribution-431-2908@cern.ch DESCRIPTION:Speakers: Yuri Lee (Istituto di Biologia e Biotecnologia Agrar ia (CNR-IBBA) 20133 Milano\, Italy)\nDuckweeds (Lemnaceae) are emerging as promising crops because of their exceptional biomass productivity and div erse applications. However\, progress toward duckweed domestication has be en limited by a poor understanding of their sexual reproduction\, which is essential to improve genetic information via breeding. Recent genomic stu dies unexpectedly revealed numerous interspecific hybrids and polyploid li neages in the genera *Lemna* and *Wolffia*\, suggesting that sexual reprod uction\, although rarely observed\, has played a much stronger evolutionar y role than previously recognized. We systematically investigated the repr oductive biology of representative *Lemna* hybrids and their parental spec ies. Furthermore\, we performed a comprehensive cytological analysis of me iosis in some selected *Lemna* species to determine the origin and frequen cy of unreduced gametes associated with polyploids formation. Our analyses revealed remarkable diversity in reproductive traits\, including protogyn y\, homogamy\, and variation in self-fertility among species. Except for t he naturally fertile allotetraploid *L*.×*aoukikusa*\, all investigated a llodiploid and triploid hybrids were sterile\, and artificial whole-genome doubling of natural allodiploid hybrids has failed to restore fertility s o far. Cytological analyses combined with fluorescence in situ hybridizati on showed both dyads and tetrads\, representing unreduced and reduced male meiotic cells\, respectively. Unreduced gametes occurred at variable\, bu t rather low frequencies (up to 6.85% in *L*. *turionifera* and 12% in *L* . *minor*)\, providing a plausible explanation for the absence of naturall y occurring tetraploids in *L*.×*japonica* and both parental species\, *L *. *minor* and *L*. *turionifera*. This study provides keys for elucidatin g evolutionary pathways of duckweeds and establishes a foundation for futu re domestication by sexual crossing of this emerging crop.\n\nhttps://indi co.unina.it/event/117/contributions/2908/ LOCATION:Department of Agricultural Sciences of the University of Napoli F ederico II\, Portici\, Italy Sala Cinese URL:https://indico.unina.it/event/117/contributions/2908/ END:VEVENT BEGIN:VEVENT SUMMARY:Wolffia arrhiza: A Cryptic Species Complex within the Genus Wolffi a DTSTART;VALUE=DATE-TIME:20260929T141500Z DTEND;VALUE=DATE-TIME:20260929T143000Z DTSTAMP;VALUE=DATE-TIME:20260921T233455Z UID:indico-contribution-431-2907@cern.ch DESCRIPTION:Speakers: Anton Stepanenko (Leibniz Institute of Plant Genetic s and Crop Plant Research (IPK) Gatersleben\, 06466 Seeland\, Germany)\nHa rnessing plant diversity is essential for modern agriculture. Duckweeds ha ve attracted increasing attention as novel crops with applications ranging from food and feed production to molecular farming. Species complexes\, w hich may involve hybridization and polyploidization events\, represent an important source of hidden genetic diversity that can be utilized for crop improvement. Recently\, species complexes have been described in the duck weed genus *Lemna* (Stepanenko et al.\, 2026\; Morello et al.\, 2026)\, su ggesting that a similar pattern may also exist within the genus *Wolffia*. However\, evolutionary relationships and species boundaries in *Wolffia* remain poorly understood due to the high morphological similarity among it s species. \nIn this study\, we used an integrated cytogenetic and molecul ar approach to investigate the diversity of *Wolffia arrhiza*. By combinin g flow cytometry\, chromosome analysis\, genomic *in situ* hybridization ( GISH)\, morphological traits\, chloroplast and nuclear DNA markers\, we id entified distinct diploid genetic lineages as well as reciprocal triploid hybrids between them.\nOur findings reveal unexpectedly high diversity wit hin *Wolffia arrhiza*\, supporting its recognition as a species complex an d highlighting the need for particular attention when describing and ident ifying accessions within this group.\n\nhttps://indico.unina.it/event/117/ contributions/2907/ LOCATION:Department of Agricultural Sciences of the University of Napoli F ederico II\, Portici\, Italy Sala Cinese URL:https://indico.unina.it/event/117/contributions/2907/ END:VEVENT END:VCALENDAR