Candidate, Department of Plant Pathology and Crop
Physiology, Louisiana State University, Baton Rouge,
Degree, Department of Biological Engineering,
Beijing University of Chemical Technology, Beijing,
recalcitrant seeds exhibit differential tolerance to
water loss. Recalcitrant seeds are not able to
tolerate desiccation and die when dried, while the
orthodox seeds can be stored dry without losing
viability for years.
is a dominant salt marsh species along the U.S.
Atlantic and Gulf Coasts, and its establishment is
important in reducing coastal erosion in Louisiana.
However, long-term preservation of S.
alterniflora is challenging because the seeds
are recalcitrant, losing viability when dried below
45% water content. Comparative proteomics between
S. alterniflora and orthodox, desiccation
tolerant S. pectinata seeds was performed to
identify heat-stable proteins that may be associated
with desiccation tolerance.
Several unique spots
present in orthodox S. pectinata but not in
recalcitrant S. alterniflora share homologies
with proteins found in other desiccation tolerant
species, group-3 late embryogenesis abundant
protein, dehydrin, cystatin,
glyceradehyde-3-phosphate dehydrogenase, stress
responsive protein, superoxide dismutase,
peroxiredoxin, ubiquitin, abscisic stress ripening
protein and nascent polypeptide associated complex;
these proteins are associated with the desiccation
tolerance in other organisms. Post-translational
modification experiments indicates that
phosphorylated cystatin proteins are uniquely
expressed in orthodox S. pectinata but
missing in recalcitrant S. alterniflora, and
several ca. 20 kDa and 60 kDa glycosylated proteins
are present in S. pectinata but not in S.
alterniflora. Absence of these differentially
expressed proteins may be the cause of recalcitrant
S. alterniflora seed death.