Chitosan and its derivatives in Lady Rosetta potatoes:In vivo gene expression modulation driving growth, yield, quality, and antibacterial defense

Abstract

This study examines how different forms and concentrations of chitosan affect the growth, minituber yield, and processing quality of the 'Lady Rosetta' potato variety. Using a two-way ANOVA method, we assessed the effects of chitosan, chitosan acetate, chitosan lactate, and N, O-Carboxymethyl chitosan, along with their interactions at various concentrations. The results show that the type of chitosan is the main factor for improvement. Specifically, chitosan lactate significantly accelerated germination to 4.1 days in Season 1 and 4.67 days in Season 2, while increasing shoot length to 37.8 cm and 35.5 cm, respectively-nearly double the height of the control group. Regarding physiological traits, a significant interaction between chitosan form and concentration was observed for all photosynthetic pigments. Notably, 0.01% chitosan acetate maximized chlorophyll a (28.8 mg/g), while 0.03% N, O-Carboxymethyl chitosan resulted in the highest carotenoid accumulation (8 mg/g). For yield, chitosan lactate achieved the highest results, reaching an average of 3.78 minitubers per plant and a weight of 21.33 g in Season 2, greatly surpassing other forms. Molecular analysis showed that chitosan lactate treatments significantly reduced AS1 and POT32 gene activity (up to 75% and 73% reduction, respectively), explaining the lower enzymatic browning and reduced acrylamide precursors. Additionally, 0.05% chitosan lactate showed strong antibacterial activity against Pectobacterium carotovorum and Ralstonia solanacearum, with inhibition zones reaching 24.66 mm. These results indicate that chitosan lactate serves as a dual-purpose biostimulant and bioprotectant, greatly enhancing both productivity and quality in potato farming.