Effects of Exogenous Application of Protocatechuic Acid and Vanillic Acid to Chlorophylls, Phenolics and Antioxidant Enzymes of Rice (Oryza sativa L.) in Submergence.

Tran Xuan,Do Khang

doi:10.3390/molecules23030620

Abstract

In this study, effects from application of protocatechuic acid (PA) and vanillic acid (VA) and their mixture on the submergence tolerance of rice were examined. The treatment of 0.01 mM PA and VA did not show significant increase of rice growth as compared to the controls. However, at higher concentrations (0.1–1.0 mM), rice shoot was elevated in submergence by 20.8–22.4%. The survival percentage of rice seedlings at any dose of PA, VA and their mixture was significantly higher than the controls. In general, the mixture of PA and VA was more active to promote shoot elongation and survival in submergence than sole treatment of either PA or VA. The amount of chlorophyll b by PA was significantly increased, while no change in chlorophyll a content was observed. VA remarkably reduced malondialdehyde quantity at three days of submergence, while no significant difference among treatment was observed in PA, the mixture, and respective controls. The two phenolic acids promoted contents of phenolics and flavonoids in rice leaves and roots, however the quantities of endogenous PA and VA in rice were not markedly differed after PA and VA treated on roots of rice seedlings. The ascorbate peroxidase and superoxide dismutase activities were enhanced, while the expression of genes encoding antioxidant enzymes was favored. VA increased the expression level of ascorbate peroxidase genes in higher levels than PA and their mixture, while no significant difference was observed in the other genes including superoxide dismutase, catalase, glutathione reductase, and peroxidase. Findings of this study showed that PA and VA increased the submergence tolerance of rice by promoting the photosynthetic and anti-oxidative processes in rice seedlings. The treatment of PA and VA mixture on seedling roots was potent to promote the submergence tolerance in rice.

Highlights

Submergence substantially causes major limitations on productivity and viability of agricultural crops worldwide
protocatechuic acid (PA) increase the survival of rice seedling, and PA showed greater survival at the maximal dose
Increases were observed in the lipid peroxidation and POD (0.680, p < 0.01), chlorophyll a and superoxide dismutase (SOD) (0.644, p < 0.05), SOD and ascorbate peroxidase (APX) (0.721, p < 0.05), whereas reverse reduction was observed in CAT and POD (−0.773, p < 0.01), and POD and glutathione reductase (GR) (0.702, p < 0.05)

Summary

Introduction

Submergence substantially causes major limitations on productivity and viability of agricultural crops worldwide. The Mekong and Red River deltas of Vietnam, the Ayeyerwaddy delta of Myanmar and the Ganges-Brahmaputra delta of Bangladesh, the central rice production areas worldwide, have been faced with submergence [1,3]. Many submergence-tolerant rice varieties have been generated using both conventional and DNA marker-assisted selection approaches. Success in using the SUB1 gene has provided the development of many submergence tolerance varieties [2]. The fact that many varieties make limited recovery after submergence exposure is one of the practical problems of those methods. Limited recovery may detrimentally affect physiological development and reproduction with significant reductions in the total productivity [7]. Improving the submergence tolerance of the current rice varieties by enhancing their physiological processes using exogenous regulatory factors during submergence is one of the promising solutions [9]

Methods

Results

Discussion

Conclusion