Genes Involved in Plant Stress Response and Evolution of their

Responsiveness

Cheng Zou

11/09/2007

The Stress Response is Unique and Vital to Plants

Soybean aphid, Aphis glycines (Photo Claudio Gratton)

Different from animals, when exposed to adverse environments, plant can not run away. So along evolution plant developed a specific system to fight against them. There are two main sources of stress, one is biotic, such as invasion of bacterium, fungi; another one is abiotic, such as cold, drought and heat. Based on the AtGenExpress experiments in Arabidopsis, of 22110 genes which are presented on the micro array, 37% genes are up or down regulated significantly by at least one stress condition. So we are interested in what kind of genes tend to have stress responsiveness and how gene function in stress response evolved

Arabidopsis Expression profile under stress condition

Type of stress

Abiotic stress

Osmotic

UV-B

Wounding

Cold4C

Heat

Genotoxic

Drought

Salt

Oxidative

Biotic stress

avrRpm1

DC3000

Flg22

GST-NPP1

HrcC-

HrpZ

LPS

P-infestans

Psph

For each condition, Up- and down-regulated genes were defined as genes with significantly higher and lower intensities (at 5% false discovery rate) with treated samples than those in controls. Non-responsive genes were defined

as genes that were not significantly up- or down-regulated.

time series

2 or 3 replicates control

Number of Up or Down regulated gene under each condition

the Breadth of Stress Response of All the Genes

Q1:What kind of families are overrepresented in up-refulated genes?

Up Regulation of Abiotic Stress

Fig1.The observed distribution of the breadth of stress response ( red dash line) was compared to random distributions calculated (box plot), by assuming that for each condition there are same number of up regulated genes and regardless interactions among different conditions. *Asterisk indicates that the differences is significant at < 0.001% level.

Up Regulation of Biotic Stress

the Breadth of Stress Response of Domain Family

Fig2.The observed distribution of the breadth of domain (dash line) was compared to random distributions calculated (box plot), by assuming that for each condition there are same number of domain families that over or underrepresented in up regulated genes, and regardless interactions among different conditions. *Asterisk indicates that the differences is significant at < 0.001% level.

Up Regulation of Abiotic Stress

Up Regulation of Biotic Stress

Domain families that over or under represented in up regulated genes

Abiotic

stress

biotic

stress

Evolution of Stress Response