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Expression Profile of Young Rice Panicle under Heat Stress
using DNA Microarray
Xianwen Zhang
1,2
, Ailing Liu
1,2
, Jie Zou
1,2
, Xiaoyun Zhou
1
, Wenfang Wang
1,2
,
Liyun Chen
3
, Xinyao Xiong
4
*, Xinbo Chen
1,2
*
1
College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha, China
2
Crop Gene Engineering Key Laboratory of Hunan Province, Hunan Agricultural University,
Furong District, Room 420, Life Science Building, Changsha City, Hunan Province 410128,China
3
Institute of Rice Science, Hunan Agricultural University, Changsha, China
4
College of Horticulture and Landscape, Hunan Agricultural University, Changsha, China
E-mail:xiongxingyao@126.com
Abstract
Heat shock has become one of the most serious stress factors to world crop yield and quality, and many
genes responsive to heat stress and other abiotic and biotic stresses have been discovered and their
functions have been elucidated. However, plant genome wide heat response mechanism still remains
unclear. Here, we reported expression profile of young rice panicle under heat stress of 40°C on the
whole genome level using rice 44k oligo-array. The results demonstrated that carbohydrate metabolism
and stress-related genes consist of major group that are affected during the time course. Hsps, Hsfs,
enzymes responsible for carbon partitioning, secondary metabolism, cell wall morphogenesis- related
genes, and ETC are all sensitive to heat, and then the stress shed influence on DNA replication, and
next on cell homeostasis, reproduction, and finally on cell cycle and photosynthesis. We tried to
establish heat response model for rice panicle, which would be valuable to crop production and
improvement.
Keywords: Heat shock; rice; Expression profile; Microarray
Rice is the most important food crop in the developing world. Considering the projected
population growth, future world rice production must be increased by 40% during the next 20 years[1].
This is a challenging task considering that several abiotic stress factors that affect cultivation of rice
(such as excess levels of salts in the soil, drought and temperature stress) are on the rise[2]. Heat stress
is one of the main abiotic stresses that limit plant biomass production and productivity, especially in
tropical and subtropical countries[3]. Recently, heat stress is a major factor limiting rice production in
southern China. High temperature is detrimental to both the vegetative and reproductive stages of
rice[4]. The development of improved elite rice varieties with enhanced tolerance to high temperature
can help in solving this problem. Temperature higher than 35℃ for more than three days during
reproductive stages can affect the pollen development and pollination and dramatically decrease the
seed setting and production. However, the molecular heat response mechanism in plants and important
food crops is still unknown. Two rice varieties, 996 and 4628 were found with significant difference in
high-temperature tolerance. The seed setting percentage of 996 and 4628 were 66.31% and 36.11%
respectively under seven days 37℃/30℃ high temperature treatment, while under natural field
condition were 81.55% and 79.32% respectively. In this report, using rice 44K oligo-array, we
performed transcriptome analysis to identify genes responsive to high temperature in the heat tolerant
cultivar 996 (Oryza sativa L. ssp. japonica) and try to elucidate the molecular response model to heat in
rice during young panicle development.
1. Materials and Methods
1.1 Plant Materials and Heat Treatment
Heat-tolerant rice cultivar 996 was cultivated in the field until phase 3-4 panicle stage, and moved to
growth cabinets pretreated under the condition of 32°C with 80% humidity at day, and 28°C with 80%
humidity at night, and then the control was collected before continuous heat treatment at 40°C with
80% humidity. Treated samples were collected at time point of 20min, 60min, 2hr, 4hr, 8hr. Young