Gene Expression Analysis of Potato (Solanum tuberosum L.) Lipoxygenase Cascade and Oxylipin Signature under Abiotic Stress.

Svetlana Gorina,Lucia Mukhtarova,Anna Ogorodnikova,Yana Toporkova

doi:10.3390/plants11050683

Abstract

The metabolism of polyunsaturated fatty acids through the lipoxygenase-catalyzed step and subsequent reactions is referred to as the lipoxygenase (LOX) pathway. The components of this system, such as jasmonates, are involved in growth, development and defense reactions of plants. In this report, we focus on dynamics of expression of different LOX pathway genes and activities of target enzymes with three abiotic stress factors: darkness, salinity and herbicide toxicity. To obtain a more complete picture, the expression profiles of marker genes for salicylic acid, abscisic acid, ethylene, auxin and gibberellin-dependent signaling systems under the same stresses were also analyzed. The gene expression in Solanum tuberosum plants was analyzed using qRT-PCR, and we found that the LOX-cascade-related genes responded to darkness, salinity and herbicide toxicity in different ways. We detected activation of a number of 9-LOX pathway genes; however, in contrast to studies associated with biotic stress (infection), the 9-divinyl ether synthase branch of the LOX cascade was inhibited under all three stresses. GC-MS analysis of the oxylipin profiles also showed the main activity of the 9-LOX-cascade-related enzymes after treatment with herbicide and darkness.

Highlights

Due to the lack of the capability to move as a means of reacting to changes in their environment, plants have to adapt to environmental stresses in other ways
We focus on dynamics of expression of different LOX pathway genes and activities of target enzymes with three abiotic stress factors: darkness, salinity and herbicide toxicity
We detected activation of a number of 9-LOX pathway genes; in contrast to studies associated with biotic stress, the 9-divinyl ether synthase branch of the LOX cascade was inhibited under all three stresses

Summary

Introduction

Due to the lack of the capability to move as a means of reacting to changes in their environment, plants have to adapt to environmental stresses in other ways. The most studied oxylipins are jasmonates, products of the allene oxide synthase (AOS) branch of the LOX cascade. Jasmonoyl-isoleucine (JA-Ile) mediating the plant cell response to biotic and abiotic stresses is the most studied [2]. Other well-studied oxylipins are green leaf volatiles (GLVs), composed of C6 aldehydes, alcohols and their esters, formed through the hydroperoxide lyase (HPL) branch of the LOX pathway. These compounds have been shown to play key roles in plant–plant and plant–herbivore interactions [6,7]. They function as signals activating systemic defense [8,9], and are involved directly in plant defense as antimicrobials. Besides GLVs, the HPL pathway results in formation of traumatic acid, which is involved in wound healing [13]

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