Peanut ( Arachis hypogaea
L.) is an important economic and oilseed crop. Long-term rainless
conditions and seasonal droughts can limit peanut yields and were conducive to preharvest aflatoxin
contamination. To elucidate the molecular mechanisms by which peanut responds and adapts to water limited
conditions, we isolated and characterized several drought-induced genes from peanut roots using a
suppression subtractive hybridization (SSH) technique.
RNA was extracted frompeanut roots subjected to a water stress treatment (45% field capacity) and from
control plants (75% field capacity), and used to generate an SSH cDNA library. A total of 111 non-redundant
sequences were obtained, with 80 unique transcripts showing homology to known genes and 31 clones with
no similarity to either hypothetical or known proteins. GO and KEGG analyses of these differentially expressed
ESTs indicated that drought-related responses in peanut could mainly be attributed to genes involved in
cellular structure and metabolism. In addition, we examined the expression patterns of seven differentially
expressed candidate genes using real-time reverse transcription-PCR (qRT-PCR) and confirmed that all were
up-regulated in roots in response to drought stress, but to differing extents.
We successfully constructed an SSH cDNA library in peanut roots and identified several
drought-related genes. Our results serve as a foundation for future studies into the elucidation of the drought
stress response mechanisms of peanut.