2026-03-25 筑波大学
＜関連情報＞
- https://www.tsukuba.ac.jp/journal/biology-environment/20260325140000.html
- https://www.tsukuba.ac.jp/journal/pdf/p20260325140000.pdf
- https://www.sciencedirect.com/science/article/pii/S0981942826000896
SlIAA9 変異はトマト種子において高温耐性を強化する SlIAA9 mutation enhances tomato seed resilience to heat stress
Bayu Pradana Nur Rahmat, Iqbal Fathurrahim Elfakhriano, Nono Carsono, Farida Damayanti, Syariful Mubarok, Hoshikawa Ken, Hiroshi Ezura, Seung Won Kang
Plant Physiology and Biochemistry Available online: 6 February 2026
DOI:https://doi.org/10.1016/j.plaphy.2026.111103
Highlights
- SlIAA9 mutants retain higher germination and seed quality after prolonged heat stress.
- iaa9-5 mutant line shows rapid post-heat recovery.
- Mutants show lower ROS and stronger heat-response gene activity.
- Ethylene signalling kickstarts germination post heat stress.
- The loss of function SlIAA9 boosts seed recovery and heat resilience.
Abstract
Heat stress during seed germination represents a critical constraint to crop establishment, yet the hormonal and genetic mechanisms governing seed resilience to heat stress remains poorly understood. In tomato (Solanum lycopersicum), the role of auxin signaling repressor SlIAA9 in regulating seed germination and responses to heat stress has not been defined. Here, we investigated how loss of function mutation in SlIAA9 affects seed resilience under high temperature and post stress recovery. Utilizing two SlIAA9 mutant lines (iaa9-5 and iaa9-3) and Wild-Type Micro-Tom tomatoes, we assessed germination behaviors, seed quality parameters, reactive oxygen species (ROS) contents, and transcriptional responses during heat stress and recovery. Both mutants exhibited enhanced resilience to heat stress, with iaa9-5 maintaining high germination rate, normal seed and seedling qualities, and rapid post-stress recovery. This phenotype was associated with reduced accumulation of H2O2 and O2− and elevated expression of antioxidant and heat-responsive genes. Heat stress triggered stronger induction of HSFA9 and HSP70 in the mutants, while dormancy associated abscisic acid (ABA) biosynthesis genes were suppressed and ethylene biosynthesis genes were upregulated during stress recovery. Together, these findings identify SlIAA9 as a negative regulator of seed resilience to heat stress and loss of SlIAA9 function enhances antioxidant capacity and heat-responsive transcriptional programs during germination and recovery. Highlighting SlIAA9 as a potential genetic target for improving seed resilience to heat stress.
