Trehalose Protects Maize Plants from Salt Stress and Phosphorus Deficiency

Md Motiar Rohman; Md Robyul Islam; Mahmuda Binte Monsur; Mohammad Amiruzzaman; Masayuki Fujita; Mirza Hasanuzzaman

doi:10.3390/plants8120568

Trehalose Protects Maize Plants from Salt Stress and Phosphorus Deficiency

Plants (Basel). 2019 Dec 4;8(12):568. doi: 10.3390/plants8120568.

Authors

Md Motiar Rohman¹, Md Robyul Islam¹, Mahmuda Binte Monsur¹, Mohammad Amiruzzaman¹, Masayuki Fujita², Mirza Hasanuzzaman³

Affiliations

¹ Molecular Breeding Lab, Plant Breeding Division, Bangladesh Agricultural Research Institute, Gazipur 1701, Bangladesh.
² Laboratory of Plant Stress responses, Faculty of Agriculture, Kagawa University, Kagawa 7610795, Japan.
³ Department of Agronomy, Faculty of Agriculture, Sher-e-Bangla Agricultural University, Sher-e-Bangla Nagar, Dhaka 1207, Bangladesh.

Abstract

This study is undertaken to elucidate the role of trehalose (Tre) in mitigating oxidative stress under salinity and low P in maize. Eight-day-old maize seedlings of two maize varieties, BARI Hybrid Maize-7 and BARI Hybrid Maize-9, were subjected to salinity (150 mM NaCl), low P (5 µM KH₂PO₄) and their combined stress with or without 10 mM Tre for 15 d. Salinity and combined stress significantly inhibited the shoot length, root length, and root volume, whereas low P increased the root length and volume in both genotypes. Exogenous Tre in the stress treatments increased all of the growth parameters as well as decreased the salinity, low P, and combined stress-mediated Na⁺/K⁺, reactive oxygen species (ROS), malondialdehyde (MDA), lipoxygenase (LOX) activity, and methylglyoxal (MG) in both genotypes. Individually, salinity and low P increased superoxide dismutase (SOD) activity in both genotypes, but combined stress decreased the activity. Peroxidase (POD) activity increased in all stress treatments. Interestingly, Tre application enhanced the SOD activity in all the stress treatments but inhibited the POD activity. Both catalase (CAT) and glutathione peroxidase (GPX) activity were increased by saline and low P stress while the activities inhibited in combined stress. Similar results were found for ascorbate peroxidase (APX), glutathione peroxidase (GR), and dehydroascorbate reductase (DHAR) activities in both genotypes. However, monodehydroascorbate reductase (MDHAR) activity was inhibited in all the stresses. Interestingly, Tre enhanced CAT, APX, GPX, GR, MDHAR, and DHAR activities suggesting the amelioration of ROS scavenging in maize under all the stresses. Conversely, increased glyoxalase activities in saline and low P stress in BHM-9 suggested better MG detoxification system because of the down-regulation of glyoxalase-I (Gly-I) activity in BHM-7 in those stresses. Tre also increased the glyoxalase activities in both genotypes under all the stresses. Tre improved the growth in maize seedlings by decreasing Na⁺/K⁺, ROS, MDA, and MG through regulating antioxidant and glyoxalase systems.

Keywords: abiotic stress; methylglyoxal; nutrient deficiency; osmolytes; oxidative stress; salinity.