Polyamine-Mediated Transcriptional Regulation of Enzymatic Antioxidative Response to Excess Soil Moisture during Early Seedling Growth in Soybean.

Gagandip K Sidhu,Fouad Daayf,Sylvie Renault,Belay T Ayele,Pham Anh Tuan

doi:10.3390/biology9080185

Abstract

This study examined the expression patterns of antioxidative genes and the activity of the corresponding enzymes in the excess moisture-stressed seedlings of soybean in response to seed treatment with polyamines, spermine (Spm) and spermidine (Spd). At the 4 day after planting (DAP) stage, the excess moisture impaired the embryo axis growth, and this effect is associated with the downregulation of superoxide dismutase (GmSOD1) expression and SOD activity in the cotyledon. Seed treatment with Spm reversed the effects of excess moisture on embryo axis growth partly through enhancing glutathione reductase (GR) activity, in both the cotyledon and embryo axis, although no effect on the GmGR expression level was evident. Excess moisture inhibited the shoot and root growth in 7 DAP seedlings, and this is associated with decreased activities of GR in the shoot and SOD in the root. The effect of excess moisture on shoot and root growth was reversed by seed treatment with Spd, and this was mediated by the increased activities of ascorbate peroxidase (APX), catalase (CAT) and GR in the shoot, and APX in the root, however, only GR in the shoot appears to be regulated transcriptionally. Root growth was also reversed by seed treatment with Spm with no positive effect on gene expression and enzyme activity.

Highlights

Soybean is one of the most economically important crops cultivated around the world for food, oil and industrial purposes
The germination of the soybean seeds was monitored over a period of 3 days using radicle with Spd or Spm was observed on the germination of the soybean seeds except those seeds treated emergence as an indicator for the completion of germination
No marked effect of the seed treatment with Spd or Spm, which exhibited a slightly lower germination percentage at 1.5 and 2 days after with Spd or Spm was observed on the germination of the soybean seeds except those seeds treated imbibition (DAI) as compared to the PA‐untreated control seeds (Figure 1)

Summary

Introduction

Soybean is one of the most economically important crops cultivated around the world for food, oil and industrial purposes. Excess moisture-induced oxygen deprivation leads to the inhibition of cellular respiration for which oxygen is required as a terminal electron acceptor, and disrupts all downstream cellular processes for which energy is required It triggers alterations in gene expression, protein synthesis and degradation, and other cellular metabolic activities [2]. All these factors negatively affect plant growth and developmental processes, and thereby cause substantial reduction in the yield of dryland crop species such as soybean, which are known to lack the ability to tolerate low oxygen growth conditions [2,3]. The process of seed germination begins with imbibition, which involves a rapid uptake of water by the dry seed and the activation of cellular respiration and other

Methods

Results

Conclusion