Flavonoid Deficiency Disrupts Redox Homeostasis and Terpenoid Biosynthesis in Glandular Trichomes of Tomato.
Plant Physiol, 2021/10/20;
Sugimoto K[1], Zager JJ[2], Aubin BS[1], Lange BM[2], Howe GA[1, 3, 4]
Affiliations
PMID: 34668550DOI: 10.1093/plphys/kiab488
Impact factor: 8.005
Abstract
Glandular trichomes are epidermal structures that provide a first line of chemical defense against arthropod herbivores and other biotic threats. The most conspicuous structure on leaves of cultivated tomato (Solanum lycopersicum) is the type-VI glandular trichome (tVI-GT), which accumulates both flavonoids and volatile terpenoids. Although these classes of specialized metabolites are derived from distinct metabolic pathways, previous studies with a chalcone isomerase 1 (CHI1)-deficient mutant called anthocyanin free (af) showed that flavonoids are required for terpenoid accumulation in tVI-GTs. Here, we combined global transcriptomic and proteomic analyses of isolated trichomes as a starting point to show that the lack of CHI1 is associated with reduced levels of terpenoid biosynthetic transcripts and enzymes. The flavonoid deficiency in af trichomes also resulted in the upregulation of abiotic stress-responsive genes associated with DNA damage and repair. Several lines of biochemical and genetic evidence indicate that the terpenoid defect in af mutants is specific for the tVI-GT and is associated with the absence of bulk flavonoids rather than loss of CHI1 per se. A newly developed genome-scale model of metabolism in tomato tVI-GTs helped identify metabolic imbalances caused by the loss of flavonoid production. We provide evidence that flavonoid deficiency in this cell type leads to increased production of reactive oxygen species (ROS), which may impair terpenoid biosynthesis. Collectively, our findings support a role for flavonoids as ROS-scavenging antioxidants in glandular trichomes.
Keywords: flavonoid; glandular trichome; metabolic regulation; reactive oxygen species; terpenoid; tomato
More resources
EndNote: Download