Dr. Mark W. DAVEY

Research Manager

Research context

The major challenge facing agriculture in the coming decades is to guarantee a stable food supply in the face of an increasing population, climate change, resource depletion and developing pathogen disease resistance. It is estimated that world population will have increased to 9 billion by 2050, but with only a limited amount of arable land available this additional increase in food production will have to come from improved production yields and exploitation of marginal lands. In addition these yield increases must occur in a sustainable manner to minimize environmental impact and soil degradation.

Expertise

Biodiversity and Molecular Genetics of Fruit Species

Traditional crop breeding programs have typically focused on improving yields in a few elite varieties. This has led to a narrowing of the gene pool, and an increased susceptibility to pathogen attack. One of my main research goals therefore is to define, understand and exploit natural genetic diversity (for example in wild relatives), to identify new genes and loci underlying novel traits for sustainable crop improvement. The main crops I am interested in are perennial hard fruit species, particularly apple (Malus x domestica), pear (Pyrus communis) and banana (Musa spp). Other crops studied include tomato, cherry and strawberry.

Quantitative genetics, SNPs and marker-assisted breeding and selection

The majority of fruit traits (e.g. yield, texture, nutritional content, flavor etc.), are continuous traits, controlled by the action of multiple genes. This means that the genetics of inheritance are highly complex and a large number of progeny need to be screened to identify elite individuals. To accelerate this screening process we are developing molecular (sequence polymorphism-based) markers for traditional and novel fruit traits using NGS sequence data. These can then be applied at the seedling stage to predict the genetic potential of adult, fruit-bearing plants. My main focus here is to understand the regulation of fruit vitamin C, vitamin A and antioxidant contents. Vitamin C is a key health compound, as well as being a central regulator of plant redox and defence processes.

Plant (A)biotic Stress Responses and induced cross-tolerance

Abiotic (environmental) stresses such as water limitation, temperature etc., annually lead to losses of up to 80% of the theoretical maximal crop yields. There is thus a huge potential to improve crop productivity and quality by understanding the mechanisms by which plants adapt and survive to unfavourable conditions. Interestingly, adaptation to abiotic stress conditions also improves resistance to subsequent pathogen challenge. This is because many of the stress response pathways share similar components. We have recently demonstrated that field adaption to high light and temperature increases post-harvest resistance to Botrytis cinerea and I am currently trying to understand the key components of this induced cross-tolerance as it could represent a sustainable manner to help improve fruit quality, but vitamin C and antioxidant metabolism again appears critical.

Technical expertises

Apple SNP-, DiP- marker development:
We have recently sequenced the transcriptomes of 14 diverse apple cultivars using Next Generation Sequencing (NGS) technologies. I have also developed the bioinformatics capacity to carry out the mapping, de novo assembly, expression analyses and SNP-calling based on this data. This has led to the identification of 5 million exonic SNPs which we are using to understand allelic diversity in key candidate gene sequences for traits of interest. This data is also being used to help develop a second generation Apple SNP-chip for genome wide association studies.

Banana fruit proteome:
We are currently constructing a database of expressed proteins in fruit of low- and high carotenoid banana and plantain fruits, to identify regulatory protein sequences.

5 Key papers

Davey MW, Graham N, Vanholme B, Swennen R, May S, Keulemans J: Heterologous oligonucleotide microarrays for transcriptomics in a non-model species; a proof-of-concept study of drought stress in Musa. BMC Genomics 2009, 10:436. (Impact factor: 3.940)

Davey MW, Kenis K, Keulemans J: Genetic control of fruit vitamin C contents. Plant Physiology 2006, 142:343-351. (Impact factor: 6.650; cites; 10)

Davey MW, Gilot C, Persiau G, Ostergaard J, Han Y, Bauw GC, Van Montagu MC: Ascorbate biosynthesis in Arabidopsis cell suspension culture. Plant Physiology 1999, 121:535-543. (Impact factor: 6.650; Cites; 68)

Østergaard J, Persiau G, Davey MW, Bauw G, Van Montagu M: Isolation of a cDNA coding for L-galactono-gamma-lactone dehydrogenase, an enzyme involved in the biosynthesis of ascorbic acid in plants. Purification, characterization, cDNA cloning, and expression in yeast. J Biol Chem 1997, 272:30009-30016. (Impact factor: 5.575; Cites; 74)

Willekens H, Chamnongpol S, Davey MW, Schraudner M, Langebartels C, Van Montagu M, Inze D, VanCamp W: Catalase is a sink for H2O2 and is indispensable for stress defence in C-3 plants. Embo Journal 1997, 16:4806-4816. (Impact factor: 8.904; Cites; 232)