Key genes involved in desiccation tolerance and dormancy across life forms

Authors: COSTA, MARIA - Wageningen University; FARRANT, JILL - University Of Cape Town; Oliver, Melvin; LIGTERINK, WILCO - Wageningen University; BUITINK, JULIA - Institut National De La Recherche Agronomique (INRA); HILHORST, HENK - Wageningen University

Submitted to: Plant Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/1/2016
Publication Date: 2/3/2016
Publication URL: http://handle.nal.usda.gov/10113/63245
Citation: Costa, M.C., Farrant, J.M., Oliver, M.J., Ligterink, W., Buitink, J., Hilhorst, H.M. 2016. Key genes involved in desiccation tolerance and dormancy across life forms. Plant Science. 251:162-168. doi: 10.1016/j.plantsci.2016.02.001.

Interpretive Summary: As the scientific community continues to strive for novel strategies to improve drought tolerance in major crops there has been a growing interest in understanding mechanisms of dehydration tolerance in resurrection plants: plants that can withstand total drying. Although progress has been made and candidate genes identified the work has been hampered by the lack of a comparative approach to identify key genes that are common to all strategies that plants employ to survive dehydration. To remedy this situation the group has compared the detailed gene expression profiles that are associated with the response of several key plant species and tissues (Seeds) to desiccation: the extreme dehydration event. A shortlist of 260 genes emerged that are common to all of the major experimental plant systems available at this time. Mutant lines for 13 of the most interesting of the 260 shortlisted genes were examined in relation to their seed desiccation tolerance capabilities as well as their seed vigour, dormancy, and longevity. We found there were significant differences compared to wild-type seeds for at least one trait in the mutant lines for 7 genes. This study reinforces the idea that core mechanisms involved in dehydration tolerance developed early in the history of life and were carried forward in a conserved manner by diverse species and life forms. These core genes are prime targets for use in conventional and biotechnological efforts to improve drought tolerance in major crops.

Technical Abstract: The ability to survive desiccation is widespread in seeds, whereas it is rare in vegetative tissues of adult flowering plants. Some genetic traits conserved among desiccation-tolerant seeds and resurrection plants have been detected but more molecular aspects need to be revealed to formulate hypotheses about common regulatory principles and mine for candidate genes to be used in improving stress tolerance in crop species. To shed light on this, we used DT-related transcriptome profiling of seeds of Arabidopsis thaliana and Medicago truncatula, and vegetative tissue of Craterostigma plantagineum and Sporobolus stapfianus, from available data bases, to search for homologs commonly accumulating or declining in relation to DT in at least three of these data sets. A shortlist of 260 genes emerged, with a significant number of genes under the control of ABI3. High similarity scores were found between these genes and desiccation-related genes in the nematode Caenorhabditis elegans (34 out of 260 genes) and the lichen Cladonia rangiferina (55 out of 260 genes). T-DNA insertion lines for 13 of the 260 shortlisted genes were phenotyped in relation to DT re-induction, seed vigour, dormancy, and longevity, with significant differences compared to wild-type seeds being found for at least one trait in T-DNA lines for 7 genes. This study reinforces the idea that core mechanisms (especially those related to protection) and key regulators (mainly ABA) involved in DT developed early in the history of life and were carried forward in a conserved manner by diverse species and life forms.