Disentangling drought-responsive traits with focus on Arabidopsis

Thonglim, A. (2023)

Doctoral Thesis

In recent decades, climate change has led to more frequent and severe drought events, causing serious consequences such as increased forest mortality and significant crop yield losses. Understanding how drought affects plants, especially economically important herbaceous species, is crucial for predicting and developing drought-resistant crops. To address this issue, this study analyzed a comprehensive dataset of anatomical and hydraulic traits in different genotypes of Arabidopsis thaliana and tomato, including both wild-type and transgenic mutants. The study also investigated the expression of four well-known drought marker genes associated with ABA-dependent and ABA-independent pathways and the impact of overexpressing the JUNGBRUNNEN1 (JUB1) gene on drought response. The findings revealed that each genotype had a unique set of traits to cope with drought, which could be categorized into two response strategies. One group enhanced their drought resistance through traits like a more negative stem P50, thicker intervessel pit membranes, a more lignified inflorescence stem, and a gradual reduction of the low initial stomatal conductance during drought. This strategy enabled them to maintain a relatively high and stable leaf water potential (Ψl). The second group, represented by JUB1 overexpression genotypes, relied primarily on maintaining a high Ψl which is possibly due to osmoprotectant accumulation in leaves, while the other traits have not been recorded. Overall, this research demonstrated the adaptive capabilities of herbaceous plants to drought conditions, highlighting the intraspecific variation in drought responses that underscores the need for a detailed assessment of drought-responsive traits to improve crop yield in a warming world.

• Arabidopsis thaliana
• Solanum lycopersicum
• Drought response
• Embolism resistance
• Intervessel pit membrane thickness
• Stem anatomy
• Leaf water potential
• Stomatal conductance
• Gene expression

• All authors: Thonglim, A.
• Supervisor: Smets, E.
• Co-supervisor: Lens, F.
• Committee: Meijer, A.H.; Welzen, P. van; Balazadeh, S.; Steppe, K.; Jansen, S.
• Qualification: Doctor (dr.)
• Awarding Institution: Institute of Biology Leiden (IBL), Faculty of Science, Leiden University
• Date: 2023-11-09
• ISBN (print): 9789464834260
• Sponsorship: Institute for the Promotion of Teaching Science and Technology; Dutch Research Council NWO (grant ALWOP.488).