Biography:

Louis Gueuning earned his degree in bioengineering with a focus on chemistry and bioindustries from UCLouvain (Belgium), graduating in 2020. During his studies, he conducted his Master thesis under the supervision of Prof. Charles Hachez at the Louvain Institute of Biomolecular Science and Technology (LIBST), where he researched trichome development in Nicotiana tabacum. Following his Master degree, he continued his research in the same group as a PhD candidate. Currently in his fourth year of PhD thesis, he is preparing to defend and publish his dissertation soon.

Abstact:
Trichomes, the epidermal outgrowths found on most aerial plant tissues, are prevalent in a vast number of plant species and can be glandular or non-glandular. As multicellular structures that develop post- embryonically, glandular trichomes serve as an excellent model for investigating fundamental aspects of cell development, such as cell fate determination, cell cycle control, division and polarity, differentiation, and cell-to-cell signaling. Despite their importance, there is a significant knowledge gap regarding the regulators of glandular trichome formation and patterning in the leaf epidermis, specifically those governing entry into the glandular trichome cell fate and progression through its developmental pathway. In this study, we focus on the functional characterization of NtWoolly, a HD-ZIPIV transcription factor, and NtRAX2-like, an R2R3 MYB transcription factor. Both genes are specifically expressed in the protoderm (developing epidermis) of leaf primordia, with their expression ceasing in mature leaves. Notably, we discovered that NtRAX2-like and NtWoolly physically interact, suggesting that their heteromerization may promote glandular trichome development. To explore their roles, we performed DAP-seq analysis on both transcription factors, revealing numerous shared direct transcriptional targets, which underscores their potential common transcriptional activation pathway. Among these targets are key regulators known for their involvement in trichome development in other plant species. Additionally, we utilized reverse genetics to generate overexpressing and knockout lines for both transcription factors, yielding significant results in terms of trichome density and the chemical composition on the surface of tobacco leaves. These findings highlight the role of NtWoolly and NtRAX2-like as a transcriptional complex regulating the early stages of glandular trichome development in Nicotiana tabacum.