Proteomics combined with BSMV-VIGS methods identified some N deficiency-responsive protein species and ABA role in wheat seedling

Abstract

Crops often encounter a soil deficiency of nitrogen (N), the most important macronutrient for plants; however, the molecular mechanism of plant responses to N deficiency remains unclear. In this study, proteome-level changes that occur in bread wheat seedlings suffering from N deficiency were investigated to identify some N deficiency-responsive protein species in bread wheat. We utilized isobaric tagging for relative and absolute quantification (iTRAQ) to measure changes in the proteome patterns of N-deficient wheat seedlings and validated the role of abscisic acid (ABA) using the barley stripe mosaic virus-induced gene-silencing (BSMV-VIGS) method. A total of 1515 N deficiency–responsive protein species were successfully identified in both root and leaf tissues of wheat seedlings suffering from 8-d N deficiency. Of these, abundance of wheat zeaxanthin epoxidase (TaZEP), a key ABA synthesis-related enzyme, was significantly upregulated, and the endogenous ABA contents also markedly increased. After TaZEP gene was further silenced using BSMV-VIGS method, BSMV-VIGS-TaZEP infected wheat seedlings showed enhanced sensitivity to N deficiency, suggesting silencing of TaZEP gene decreased the tolerance to N deficiency remarkably. Our results identified some N deficiency-responsive protein species and revealed the role of ABA in wheat responses to N deficiency.