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Dr.
Andrew G. McCubbin
.jpg) 509-335-7916
amccubbin@wsu.edu
Associate
Professor in the School of Biological Sciences. P.h.D. 1993,
Reading University (U.K).
Research
The
research in our lab is centered on the developmental processes
and signaling events associated plant reproduction. Presently
we have 2 main foci, first signaling events involved in pollen
tube growth, in particular to role of calcium dependent protein
kinases (CDPK’s)
in signal transduction in this process. Pollen tubes extend by
tip-growth and it is well established that there is a steep tip
focused calcium gradient and there is evidence that CDPK isoforms
may by involved in downstream signaling events. We are investigating
this using negative dominance and catalytically modified CDPK
constructs as well as searching for CDPK substrates using the
yeast 2-hyrid system.
The
second focus is on the heteromorphic self-incompatibility (HSI)
system in Primula. HSI promotes out-breeding through a physiological
recognition system combined with a set of morphological characteristics.
In Primula there are two floral morphs, which exhibit reciprocally
positioned anthers and stigma. Pollen number and size, and the
size and shape of stigmatic and stylar cells also differ between
morphs, and these characters act synergistically to prevent inbreeding.
HSI is controlled by a diallelic S-locus, the short style (thrum)
morph is determined by the dominant S allele being Ss in genotype
and the long styled (pin) morph is homozygous recessive (ss).
Studies have shown that this S-locus is in fact a supergene – a
number of tightly linked genes with the alleles of at least 7
loci linked and inherited as a single unit. Identification and
characterization of the genes which make up the supergene has
the potential to make a significant impact of our understanding
of floral biology, not just in the functioning and evolution
of HSI systems, but also in the regulation of floral morphology
(cell size and shape) and male reproductive capacity (pollen
number). This project offers an opportunity to study several
key aspects of plant reproductive biology and will provide new
insights into the evolution and control of plant breeding systems.
In addition recent developments in the use of transgenic crops
have led to concerns about the escape of transgenes into wild
relatives. One way to address this problem would be to reproductively
isolate crop species, studies such as this of the coordination
of floral traits to produce breeding barriers will make a valuable
contribution to achieving this goal.
Selected
Publications
Yoon, G.M., Dowd, P.E., Gilroy, S. and McCubbin, A.G. 2006. Calcium-Dependent
Protein Kinase isoforms have distinct functions in pollen tube
growth, including regulating polarity. Plant Cell 18:867-878.
McCubbin, A.G., Lee, C., and Hetrick, A. 2006. Identification
of genes showing differential expression between morphs in developing
flowers of Primula vulgaris. Sexual Plant Reproduction 19:51-62.
McCubbin, A.G. and Roalson, E.H. 2005. Construction of bacterial
artificial chromosome libraries for use in phylogenetic studies.
Methods Enzymol. 395:384-399.
McCubbin, A.G. 2005. Lessons on signaling in plant self-incompatibility
systems. In: Intercellular Communication in Plants” (Annual
Plant Review Series) Ed. A. Fleming. Blackwell Publishing: pp.
240-275.
McCubbin, A.G., Ritchie, S.M., Swanson, S.J. and Gilroy, S. 2004.
The calcium-dependent protein kinase HvCDPK1 mediates the gibberellic
acid response of the barley aleurone through regulation of vacuolar
function. Plant J. 39:206-218.
Sijacic, P., Wang, X., Skirpan,
A.L., Wang, Y., Dowd, P.E., McCubbin, A.G., Huang, S. and Kao,
T.-h. 2004. Identification of the pollen determinant of S-RNase-mediated
self-incompatibility. Nature 429:302-305.
Wang, Y., Tsukamoto, T., Yi,
K.-w., Wang, X., Huang, S., McCubbin, A.G. and Kao, T.-h. (2004)
Chromosome walking in the Petunia
inflata self-incompatibility (S-) locus and gene
identification in an 881-kb contig containing S2-RNase.
Plant Mol. Biol. 54:727-742.
Wang, Y., Wang, X., McCubbin, A.G., and Kao, T.-h. 2003. Genetic
mapping and molecular characterization of the self-incompatibility
(S-) locus in Petunia inflata. Plant Mol. Biol. 53:565-580.
Roalson E.H. and McCubbin A.G. 2003. S-RNases and sexual incompatibility:
structure, functions, and evolutionary perspectives. Molecular
Phylogenetics and Evolution 29:490-506.
McCubbin, A.G. and Kao, T.-h. 2000. Molecular recognition and
response in pollen and pistil interactions. Annual Review of Cell
and Developmental Biology 16:333-364.
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