TohpreproHypSys- A Gene Expression and Defense Protein Activity in the Tobacco Wounding Response

Abstract

Tobacco hydroxyproline-rich glycopeptide systemin precursor A (TobpreproHypSys-A), from which TobHypSys I and II are released, plays a crucial role in defense responses. Here, we investigated the expression otTobpreproHypSys- A and the activity of defense proteins in tobacco organs during wounding. Expression was induced more rapidly in upper, non-wounded leaves than in lower, wounded leaves. At 24 h after mechanical wounding, expression was tow in the roots, but increased in the stems and flowers, although to a lesser extent than in the leaves. At 3 or 10 d after insect-wounding, expression did not differ among organs, suggesting thatTobpreproHypSys- A could be induced globally and continuously throughout such stress. During that period, the activity of two defense proteins — PPO and PI — was consistent with the expression ofTobpreproHyp- Sys- A in various organs. This indicates that those proteins also could be regulated by TobHypSys, both globally and continuously.