Putrescine: A Key Metabolite Involved in Plant Development, Tolerance and Resistance Responses to Stress

Abstract

Putrescine (Put) is the starting point of the polyamines (PAs) pathway and the most common PA in higher plants. It is synthesized by two main pathways (from ornithine and arginine), but recently a third pathway from citrulline was reported in sesame plants. There is strong evidence that Put may play a crucial role not only in plant growth and development but also in the tolerance responses to the major stresses affecting crop production. The main strategies to investigate the involvement of PA in plant systems are based on the application of competitive inhibitors, exogenous PAs treatments, and the most efficient approaches based on mutant and transgenic plants. Thus, in this article, the recent advances in understanding the role of this metabolite in plant growth promotion and protection against abiotic and biotic stresses will be discussed to provide an overview for future research.

Keywords: abiotic stress; biotic stress; plant growth; putrescine.

Figure 1

Putrescine biosynthesis and catabolism in plants. The green words indicate the enzyme activities, and the red ones followed by a cross are referred to competitive enzyme inhibitors (DFMA: difluoromethylarginine; DFMO: difluoromethylornithine; D-Arg: D-Arginine; CHA: cyclohexylamine). Adapted from Wojtasik et al. [20] and Chen et al. [4].

Figure 2

Developmental and biochemical changes produced in plants under Put treatment. FW: fresh weight; DW: dry weight; IAA: indole acetic acid; GA: gibberellins; CK: cytokinins; ET: ethylene.