High-Density Chitosan Induces a Biochemical and Molecular Response in Coffea arabica during Infection with Hemileia vastatrix

Abstract

The coffee industry faces coffee leaf rust caused by Hemileia vastratix, which is considered the most devastating disease of the crop, as it reduces the photosynthetic rate and limits productivity. The use of plant resistance inducers, such as chitosan, is an alternative for the control of the disease by inducing the synthesis of phytoalexins, as well as the activation of resistance genes. Previously, the effect of chitosan from different sources and physicochemical properties was studied; however, its mechanisms of action have not been fully elucidated. In this work, the ability of food-grade high-density chitosan (0.01% and 0.05%) to control the infection caused by the pathogen was evaluated. Subsequently, the effect of high-density chitosan (0.05%) on the induction of pathogenesis-related gene expression (GLUC, POX, PAL, NPR1, and CAT), the enzymatic activity of pathogenesis-related proteins (GLUC, POX, SOD, PPO, and APX), and phytoalexin production were evaluated. The results showed that 0.05% chitosan increased the activity and gene expression of ß-1,3 glucanases and induced a differentiated response in enzymes related to the antioxidant system of plants. In addition, a correlation was observed between the activities of polyphenol oxidase and the production of phytoalexin, which allowed an effective defense response in coffee plants.

Organic vs. Integrated-Production Agriculture Farming: Which Grapevine Stress-Responsive Genes Are Affected by the Application of Resistance Inducers and Elicitors?

“…This activation enhances the plant's protection against common vineyard diseases, such as powdery and downy mildew [41,42]. Similar outcomes have been observed in diverse plant species, including tomato and Coffea arabica [44,45], highlighting the importance on understanding the impact of PRIs on plants.…”

“…Although PAL did not exhibit significant differences in gene expression levels, we verify that STS1 showed significant differences between production modes in 'Alicante Bouschet', with a tendency towards significance in 'Trincadeira'. A previous study carried out on a 50-year-old vineyard in Greece reported that chitosan and abscisic acid induce phenylpropanoid gene expression, including PAL [44]; an increase of expression and enzyme activity of both PAL and STS1 was verified using a suspension of the epiphytic yeast Aureobasidium pullulans, which was potentially used as a PRI [45].…”