Eleven <i>StOSMs</i> Genes in the Potato Genome Response to Water Deficiency

Abstract

Osmotin plays an important role in plant response to low temperature and pathogen infection. To date little is known on existence and full function of OSM genes in genome-wide. In this study, based on an OSM expression sequence tag identified from a drought-treated subtractive library, StOSMs in the potato genome were identified and characterized in response to a water deficit gradient. BLAST and bioinformatic analysis revealed that there are at least eleven StOSMs in the potato genome. Among eleven StOSMs, eight StOSM mRNAs accumulated in leaf at the drought-lethal critical point (DLP) were at least 4-fold higher than in the control. The peak StOSM-8E mRNA accumulation was 49-fold higher than the control. Three StOSM mRNAs in leaf at DLP were 9.2-fold lower than in the control. This result of qRT-PCR quantification was identical with the FPKM values of all eleven StOSMs examined in the the Potato Genome Sequence database (PGSD). In conclusion, water deficiency does induce the regulation of the expression of the eleven StOSMs. Either up or downregulated by water deficiency, StOSMs play a positive role in enhancing potato tolerance to drought stress. Therefore, osmotins can be considered to be drought responsive molecules involved in withstanding water deficits. The result provides an evidence to reveal how potato adapts to drought stress.