E183K Mutation in Chalcone Synthase C2 Causes Protein Aggregation and Maize Colorless

Abstract

Flavonoids give plants their rich colors and play roles in a number of physiological processes. In this study, we identified a novel colorless maize mutant showing reduced pigmentation throughout the whole life cycle by EMS mutagenesis. E183K mutation in maize chalcone synthase C2 (ZmC2) was mapped using MutMap strategy as the causal for colorless, which was further validated by transformation in Arabidopsis. We evaluated transcriptomic and metabolic changes in maize first sheaths caused by the mutation. The downstream biosynthesis was blocked while very few genes changed their expression pattern. ZmC2-E183 site is highly conserved in chalcone synthase among Plantae kingdom and within species’ different varieties. Through prokaryotic expression, transient expression in maize leaf protoplasts and stable expression in Arabidopsis, we observed that E183K and other mutations on E183 could cause almost complete protein aggregation of chalcone synthase. Our findings will benefit the characterization of flavonoid biosynthesis and contribute to the body of knowledge on protein aggregation in plants.

Developmental regulation and physical interaction among enzymes involved in sorgoleone biosynthesis

“…However, SbARS1 was detected in the endosomal fraction and interacted with ER-localized SbDES3 (Figures 6e and 7a), suggesting that some fraction of SbARS1 associates with the ER even though we could not detect an SbARS1-GFP signal in the ER membrane. These results are reminiscent of those from chalcone synthase (CHS; Dong et al, 2021), an enzyme that is distantly related to ARS (Cook et al, 2010) which catalyzes the committing step for flavonoid biosynthesis via condensation of p-coumaroyl-CoA and three malonyl-CoA molecules (Winkel-Shirley, 2001). CHS is a part of a loosely associated, ordered complex on the ER surface and associates with many enzymes in the flavonoid pathway (reviewed in Nakayama et al, 2019).…”

Chalcone Synthase-Encoding RdCHS1 Is Involved in Flavonoid Biosynthesis in Rhododendron Delavayi

“…Flavonoids are a large group of plant natural pigments which comprise of chalcones, aurones, flavones, isoflavones, flavandiols, flavonols, proanthocyanins, anthocyanins and so on [3]. In addition to tissue pigmentation, flavonoids also fulfill significant roles in multiple physiological processes, such as UV protection, auxin transport, phytopathogens and herbivores defense, signaling between plants and microbes as well as pollen development [4,5]. Importantly, flavonoids have a wide variety of health benefits to human, including delay the aging of immune organs and nervous system, eyesight improvement, prevention of the cancer, Alzheimer's diseasea and cardiovascular disease [6,7].…”

Chalcone-Synthase-Encoding RdCHS1 Is Involved in Flavonoid Biosynthesis in Rhododendron delavayi

“…Flavonoids are a large group of plant natural pigments that comprise chalcones, aurones, flavones, isoflavones, flavandiols, flavonols, proanthocyanins, anthocyanins, and so on [3]. In addition to tissue pigmentation, flavonoids also fulfill significant roles in multiple physiological processes, such as UV protection, auxin transport, phytopathogens, defense against herbivores, signaling between plants and microbes, and pollen development [4,5]. Importantly, flavonoids provide a wide variety of health benefits to humans, including delaying the aging of immune organs and the nervous system, eyesight improvement, and the prevention of cancer, Alzheimer's disease, and cardiovascular disease [6,7].…”