Quercetin Mediated Salt Tolerance in Tomato through the Enhancement of Plant Antioxidant Defense and Glyoxalase Systems.

Parvin Parvin,Fujita Fujita,Hasanuzzaman Hasanuzzaman,Mohsin Mohsin,Bhuyan Bhuyan

doi:10.3390/plants8080247

Abstract

Quercetin (Qu) is a strong antioxidant among the phenolic compounds having physiological and biochemical roles in plants. Hence, we have studied the Qu evolved protection against salinity in tomato (Solanum lycopersicum L.). Salinity caused ionic toxicity by increasing Na+ content in seedlings along with nutritional starvation of K+, Ca2+, and Mg2+. While osmotic stress was detected by higher free proline (Pro) content and lower leaf relative water content (LRWC) in salt-stressed seedlings. Salt toxicity also induced higher H2O2 generation, malondialdehyde (MDA) content and lipoxygenase (LOX) activity as a sign of oxidative stress. Tomato seedlings suffered from methylglyoxal (MG) toxicity, degradation of chlorophyll, along with lower biomass accumulation and growth due to salt exposure. However, Qu application under salinity resulted in lower Na+/K+ due to reduced Na+ content, higher LRWC, increased Pro, and reduction of H2O2 and MDA content, and LOX activity, which indicated alleviation of ionic, osmotic, and oxidative stress respectively. Quercetin caused oxidative stress, lessening through the strengthening of both enzymatic and non-enzymatic antioxidants. In addition, Qu increased glutathione S-transferase activity in salt-invaded seedlings, which might be stimulated reactive oxygen species (ROS) scavenging along with higher GSH content. As a result, toxic MG was detoxified in Qu supplemented salt-stressed seedlings by increasing both Gly I and Gly II activities. Moreover, Qu insisted on better plant growth and photosynthetic pigments synthesis in saline or without saline media. Therefore, exogenous applied Qu may become an important actor to minimize salt-induced toxicity in crops.

Highlights

Salinity is a major abiotic constraint for limiting plant growth; physiology and development lead to yield loss [1]
Salt-stress reduced tomato seedling growth confirmed from lowering of shoot length, root length, and stem girth, compared to control (Figure 1A–C); while salt-induced lower biomass accumulation was indicated by reduced fresh weight (FW) and dry weight (DW) of both shoots and roots (Figure 2A–D)
Results indicate that exogenous Qu supplementation improved seedling growth and biomass accumulation under both saline and non-saline conditions (Figures 1A–C and 2A–D), where 25 μM Qu showed the best growth healing except for root FW and DW, which was best from 15 μM Qu supplementation under both stressed and non-stressed conditions

Summary

Introduction

Salinity is a major abiotic constraint for limiting plant growth; physiology and development lead to yield loss [1]. Major secondary stresses—including nutrient deficit, osmotic, and oxidative stress—occur in plants. Salt stress causes higher water potential in the root zone and restricts water uptake causing osmotic stress. Plants suffer from nutrients deficiency due to limited. Plants 2019, 8, 247 nutrient uptake, as well as the transport to growing parts [1]. The plant suffers from ionic stress due to increasing Na+ /K+ ratio with higher Na+ influx and K+ efflux [2,3].

Methods

Results

Discussion

Conclusion