Leaf Proteomic Analysis in Seedlings of Two Maize Landraces with Different Tolerance to Boron Toxicity

Boron (B) toxicity is an important stressor that negatively affects maize yield and the quality of the produce. The excessive B content in agricultural lands is a growing problem due to the increase in arid and semi-arid areas because of climate change. Recently, two Peruvian maize landraces, Sama and Pachia, were physiologically characterized based on their tolerance to B toxicity, the former being more tolerant to B excess than Pachia. However, many aspects regarding the molecular mechanisms of these two maize landraces against B toxicity are still unknown. In this study, a leaf proteomic analysis of Sama and Pachia was performed. Out of a total of 2793 proteins identified, only 303 proteins were differentially accumulated. Functional analysis indicated that many of these proteins are involved in transcription and translation processes, amino acid metabolism, photosynthesis, carbohydrate metabolism, protein degradation, and protein stabilization and folding. Compared to Sama, Pachia had a higher number of differentially expressed proteins related to protein degradation, and transcription and translation processes under B toxicity conditions, which might reflect the greater protein damage caused by B toxicity in Pachia. Our results suggest that the higher tolerance to B toxicity of Sama can be attributed to more stable photosynthesis, which can prevent damage caused by stromal over-reduction under this stress condition.

Automated summary

Boron (B) toxicity negatively affects maize yield and quality. Peruvian maize landraces, Sama and Pachia, were characterized based on their tolerance to B toxicity, with Sama being more tolerant. A proteomic analysis revealed differentially accumulated proteins related to various processes including transcription, translation, metabolism, and degradation. Pachia showed greater protein damage and higher expression of proteins related to degradation and transcription under B toxicity, while Sama displayed more stable photosynthesis.