Expression Profile in Rice Panicle: Insights into Heat Response Mechanism at Reproductive Stage

Xianwen Zhang,Ailing Liu,Xinbo Chen,Wirat Rerksiri,Jiaping Li,Yan Peng,Xingyao Xiong,Jianhua Xiang,Jie Zou,Xiaoyun Zhou,Dongsheng Zhou

doi:10.1371/journal.pone.0049652

Abstract

Rice at reproductive stage is more sensitive to environmental changes, and little is known about the mechanism of heat response in rice panicle. Here, using rice microarray, we provided a time course gene expression profile of rice panicle at anther developmental stage 8 after 40°C treatment for 0 min, 20 min, 60 min, 2 h, 4 h, and 8 h. The identified differentially expressed genes were mainly involved in transcriptional regulation, transport, cellular homeostasis, and stress response. The predominant transcription factor gene families responsive to heat stress were Hsf, NAC, AP2/ERF, WRKY, MYB, and C2H2. KMC analysis discovered the time-dependent gene expression pattern under heat stress. The motif co-occurrence analysis on the promoters of genes from an early up-regulated cluster showed the important roles of GCC box, HSE, ABRE, and CE3 in response to heat stress. The regulation model central to ROS combined with transcriptome and ROS quantification data in rice panicle indicated the great importance to maintain ROS balance and the existence of wide cross-talk in heat response. The present study increased our understanding of the heat response in rice panicle and provided good candidate genes for crop improvement.

Highlights

The burden of environmental stresses on crop plants is likely to increase because of global warming, and heat stress is a major abiotic stress limiting plant growth and productivity in many areas of the world [1]
H2O2 is an early component of the heatsignaling pathway [5], which is required for the activation of small heat shock proteins synthesis as well as the over-production of the reactive oxygen species (ROS) scavengers such as catalase, superoxide dismutase and peroxidase [4]
We identified 8 HR transcription factors (TFs) families that include Hsf, AP2/ERF, bHLH, bZIP, Myb, WRKY, NAC and C2H2

Summary

Introduction

The burden of environmental stresses on crop plants is likely to increase because of global warming, and heat stress is a major abiotic stress limiting plant growth and productivity in many areas of the world [1]. It’s well known that heat shock directly or indirectly leads to the production of reactive oxygen species (ROS) like H2O2, which is called oxidative stress [4]. H2O2 is an early component of the heatsignaling pathway [5], which is required for the activation of small heat shock proteins (sHSP) synthesis as well as the over-production of the ROS scavengers such as catalase, superoxide dismutase and peroxidase [4]. The induction of heat-shock protein (HSP) expression is one of the best-characterized responses to high temperature stress, which is similar mechanism of response to high temperatures in all organisms [6,7,8]. A lot of heat-responsive genes and proteins including Hsps, Hsfs, antioxidant enzymes, various transcription factors and calmodulin have been identified and their functions were well elucidated [9,10,11,12]

Methods

Results

Conclusion