Benildo G. de los Reyes

Benildo G. de los Reyes


Assistant Professor of Plant Molecular Genetics
Ph.D., Oklahoma State University, 1999

E-Mail: benildo.de@maine.edu
Telephone: 207-581-2564
Fax: 207-581-2537

Research topics: Functional and comparative genomics of abiotic stress tolerance mechanisms in higher plants; Gene regulation and allele mining.

Research program: My laboratory is using various plant models to investigate the molecular genetics of quantitatively inherited variation in tolerance to abiotic stresses. Our long-term goal is to define the signaling pathways and gene regulatory networks involved in adaptation to low temperature, dehydration and osmotic stresses by integrated molecular approaches that include functional and comparative genomics, forward and reverse genetics, biochemistry and physiology. Our current research projects are the following: 1) Genetic networks integrating cold stress responses and seedling development in rice. --- Rice (Oryza sativa L.) is sensitive to chilling at early stages of seedling establishment. Given its complex biochemical nature, the genotypic basis of adaptive responses must rely on intricate mechanisms that integrate stress responses and developmental processes. Using the newly completed japonica genome sequence, a 6,000-unigene set 'stress response' cDNA microarray (Theor Appl Genet 107:1071-1082; http://tinyurl.com/3gztb), and a 'whole genome' (40,000 genes) oligonucleotide microarray of rice (www.ricearray.org), we are conducting an analysis of the low temperature-induced changes in the transcriptome during emergence and post-emergence developmental stages. The project aims to identify the: a) Critical biochemical pathways associated with cold tolerance mechanisms based on genotype-specific gene expression signatures; b) Downstream effectors of the cold stress response regulatory circuit; and c) Upstream activators of the cold stress response regulon based on coordinated expression of transcription factors and the battery of downstream genes containing the corresponding target promoter cis-elements. The knowledge generated from this study establishes the foundation for future use of regulon engineering for the development of stress tolerant crops. 2) Novel stress tolerance mechanisms in plants. --- The exotic germplasm is a rich reservoir of major genes that define plant adaptation to marginal environments. The centerpiece of this project is to compare the stress response mechanisms among the representative genotypes of cultivated species and their wild relatives with varying degrees of tolerance to different sub-optimal environments by global analysis of the stress response transcriptome. The long-term goal is to identify the major gene regulons associated with novel tolerance mechanisms. Our hypothesis is that these mechanisms are defined by allelic variants of major regulatory genes, which have been left behind in the exotic gene pool during crop domestication. One of the current emphases of this research is the molecular characterization of allelic variation for the AP2/EREBP-type family of stress-related transcription factors. We are investigating if sequence polymorphism within the promoters of different orthologous and paralogous activators contribute to quantitative variation in their expression and differences in the activity of target transcriptional clusters. This project aims to explain the wide differences in stress tolerance among cultivated and wild species through this hypothesis. Reference crop models that are amenable to wide hybridization are currently being used for this project (i.e., Oryza spp: sativa, glaberrima, australiensis, coarctata; and Solanum spp: tuberosum, commersonnii, bolviense, trifidum).

Selected Publications