Comparative Transcriptional Profiling of Melatonin Synthesis and Catabolic Genes Indicates the Possible Role of Melatonin in Developmental and Stress Responses in Rice.

Yunxie Wei,Wei Hu,Chaozu He,Haitao Shi,Lanzhen Chen,Hongqiu Zeng

doi:10.3389/fpls.2016.00676

Abstract

As a well-known animal hormone, melatonin (N-acetyl-5-methoxytryptamine) is also involved in multiple plant biological processes, especially in various stress responses. Rice is one of the most important crops, and melatonin is taken in by many people everyday from rice. However, the transcriptional profiling of melatonin-related genes in rice is largely unknown. In this study, the expression patterns of 11 melatonin related genes in rice in different periods, tissues, in response to different treatments were synthetically analyzed using published microarray data. These results suggest that the melatonin-related genes may play important and dual roles in rice developmental stages. We highlight the commonly regulation of rice melatonin-related genes by abscisic acid (ABA), jasmonic acid (JA), various abiotic stresses and pathogen infection, indicating the possible role of these genes in multiple stress responses and underlying crosstalks of plant hormones, especially ABA and JA. Taken together, this study may provide insight into the association among melatonin biosynthesis and catabolic pathway, plant development and stress responses in rice. The profile analysis identified candidate genes for further functional characterization in circadian rhythm and specific stress responses.

Highlights

Melatonin (N-acetyl-5-methoxytryptamine) was first discovered in the cow’s pineal gland (Lerner et al, 1958). Dubbels et al (1995) and Hattori et al (1995), melatonin was identified in plants by two research groups
Melatonin has been found in multiple plant species, including alfalfa, almond, anise, apples, Arabidopsis, banana, beetroot, bermudagrass, black mustard, cabbage, celery, Abbreviations: 2-ODD, 2-oxoglutarate-dependent dioxygenase; AANAT, arylalkylamine N-acetyltransferase; ABA, abscisic acid; aceylserotonin O-methyltransferase (ASMT), N-aceylserotonin methyltransferase; AXR3, Auxin Resistant 3; BL, indole-3-acetic acid; DAT, days after transplanting; GA, gibberellic acid; GEO, Gene Expression Omnibus; hpi, hour post inoculation; IAA, indole-3-acetic acid; JA, jasmonic acid; M2H, melatonin 2-hydroxylase; SNAT, serotonin N-acetyltransferase; T3S, type III secretion system; T5H, tryptamine 5-hydroxylase; TDC, tryptophan decarboxylase; tZ, trans-zeatin; Xoo, Xanthomonas oryzae pv. oryzae
To investigate the expression profiles of rice melatonin synthesis and catabolic genes in various tissues or organs, we analyzed the expression of these genes using published microarray data (Sato et al, 2013)

Summary

Introduction

Melatonin (N-acetyl-5-methoxytryptamine) was first discovered in the cow’s pineal gland (Lerner et al, 1958). Dubbels et al (1995) and Hattori et al (1995), melatonin was identified in plants by two research groups. Melatonin in plants can be synthesized by four sequential enzymes from tryptophan (Kang et al, 2011), including TDC, T5H, SNAT, and N-aceylserotonin O-methyltransferase (ASMT) (Arnao and Hernández-Ruiz, 2014, 2015; Zuo et al, 2014). Gene families of TDC, T5H, SNAT, and ASMT contain 3, 1, 1, and 3 known members, respectively (Kang et al, 2007; Fujiwara et al, 2010; Kang et al, 2013; Park et al, 2013a). OsM2H genes belong to 2-ODD family and at least 4 of 2-ODD genes show M2H activities in rice (Byeon and Back, 2015)

Methods

Results

Conclusion