RNA sequencing analysis of stress responses of faba bean (Vicia faba L.) to rootzone acidity and aluminum toxicity

Abstract

Soil acidity limits the growth and development of crops. Yield of plants decreases due to not only low pH conditions in acid soils but also dissolution of detrimental elements affecting the availability of essential nutrients. Aluminum toxicity have been one major cause of decline in yield due to the stunting of the primary root and inhibition of lateral root formation. Plants have ways to mitigate aluminum toxicity which includes Al exclusion mechanisms as a first defense to external Al ions and Al detoxifying mechanisms where Al ions are transported and sequestered inside the plant cells. Vicia faba, commonly known as faba or broad bean is one of the oldest crops grown for being a cheap but excellent foundation of protein in human diets, a good fodder and a forage crop for animals, and one of the most powerful nitrogen fixers. The crop is well adapted to low temperatures but moderately susceptible to hostile subsoils and has very low exchangeable Aluminum tolerance. Responsive varieties were previously identified but mechanisms to counteract with the conditions are still to be realized hence the study aimed to understanding the molecular mechanisms of rootzone aluminum toxicity tolerance in faba bean which was realized by using RNA-Seq technique to analyze the transcriptome of roots of faba bean exposed to acidic and aluminum stressed environment and by then, Al responsive genes were identified. The administration of stress was done in a aquaponics set-up. Results revealed that although gene directly interacting with Al was not identified, faba bean have a variety of well-adapted mechanisms to encounter with the Al stressed condition and mitigate the adverse effects to the plant growth and development which includes (1)transporter activity, (2)signaling(ROS), and (3)ubiquitination. The findings will provide valuable information for designing future crop breeding programs.