Poster: Seed Biology
Abs #
537: Protein profiling in the oldest living seeds: Sacred Lotus Nelumbo nucifera
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Presenter: |
Shen-Miller, J. , shenmiller@biology.ucla.edu | Authors | Shen-Miller, J. (A) Wooding, Kerry (B) Zhang, Heidi Y. (B) Loo, Joseph A. (B) Lindner, Petra (C) Ogorzalek Loo, Rachel R. (B) | | Affiliations: |
(A): Dept Organismic Biol, Ecol, Evol, Univ CA, Los Angeles
(B): Dept Biol Chem, Univ CA, Los Angeles
(C): Inst Med Microbiol & Hygiene, Regensburg Univ, Germany
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Sacred Lotus, a primitive angiosperm, has 8 chromosomes with a small genome DNA 4C=0.97pg, vs. 0.7pg of that of Arabidopsis. It holds the world's record of seed longevity, 1300y, with 80% viability in 200 to 1300 y-old fruits (Shen-Miller et al., 2002, Am J Bot, 89). For sprouting after 3-4d of imbibition, an old seed has to repair damage accrued over long-term aging. Accumulated low-dose soil g-radiation of 3Gy (1Gy=100rad) did not affect viability (Shen-Miller, 2002, Seed Sci Res, 12). Lotus embryo axes contain chlorophyll & Rubisco, and showed 50% germination with 90oC treatment. Their proteins also show heat hardiness. Large and small chaperonins, stress protein dehydrin, and aa-repair enzyme IAMT retain solubility/activity after 50o or 110oC. Parts of the most abundant ~55kDa protein show much sequence similarity to a 66kDa 7S-storage protein of oil palm and those of Arabidopsis, sesame, and jack bean. The N-terminus of a ~35kDa protein is identical to the 55kDa, and that of a ~45kDa shows 77% sequence ID with an Arabidopsis LEA protein and greater ID with bacterial Hsp60s. From preliminary MALDI-TOF (matrix assisted laser desorption ionization-time of flight) spectra and sequencing with electrospray quadrupole TOF mass spectrometer, a peptide from the 35kDa protein is identical to one sequence in a rice blast-resistant Pi-ta protein. One segment of a ~50kDa protein has sequence similarity to soybean 7-S storage protein b-conglycinin and plant glucose-6-phosphate dehydrogenases. We will report further on de novo sequencing by tandem MS of lotus heat-hardy proteins from 1D and 2D gels digested in the presence of labeled H2O and cleaved after modified residues of Cys and Lys (Thevis & Loo, J Proteome Res, in press).
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