Title: Proteomic Analysis of B-Aminobutyric Acid-Primed Drought Resistance in Crabapple Seedlings Authors
Submitted to: Bio-Technology Fruit Symposium
Publication Type: Abstract Only
Publication Acceptance Date: March 30, 2008
Publication Date: September 1, 2008
Citation: Macarisin, D., Wisniewski, M.E., Bassett, C.L., Thannhauser, T.W. 2008. Proteomic analysis of b-aminobutyric acid-primed drought resistance in crabapple seedlings. Bio-Technology Fruit Symposium. Acta Hort. Book of Abstracts. 16:95. Technical Abstract: In a variety of annual crops and some model plant species, the non-protein, amino acid, DL-B-aminobutyric acid (BABA), has been shown to enhance disease resistance and increase salt and drought tolerance, through sensitization, and not direct induction of defense genes. This process is referred to as chemical priming. Primed plants do not suffer from costly defense investments (such as inhibition of photosynthesis) since their defense arsenal is not activated before stress exposure. However, there are no reports on BABA-induced resistance in woody species. Additionally, the metabolic pathways through which BABA mediates both abiotic and biotic stress resistance are still being elucidated. In the present study, drought tolerance of four-week-old crabapple (Malus prunifolia) seedlings was significantly increased (P less than or equal to 0.05) following a soil drench treatment with 500 uM BABA. On the tenth day after cessation of watering, the level of water loss in BABA-primed seedlings was 2-3 fold less than that of untreated plants, clearly indicating the ability of BABA to induce tolerance to drought stress in perennial plants. 2-D Difference in-Gel Electrophoresis (DiGE) was employed to characterize and compare differences in protein expression in leaf tissue sampled from control, BABA-primed and ABA-treated seedlings exposed to drought stress. A comparison of the different treatment combinations on the third and tenth day of dehydration revealed that 102 and 202 proteins, respectively, were differently expressed (P less than 0.05), in at least one condition. Among those, there were proteins that showed almost identical patterns of upregulation (57) or down regulation (34) in BABA and ABA treated seedling that supports the general concept suggesting that BABA-induced resistance in plants is achieved by potentiating ABA-regulated pathway. However, some differentially expressed classes of proteins were uniquely up-regulated (54) and down-regulated (38) only in BABA-primed plants, indicating that BABA may also mediate resistance via some ABA-independent pathways. MALDI-TOF MS/MS is being utilized to identify the proteins of interest. A quantitative analysis of the proteomes of control, ABA and BABA-treated tissue will be presented together with the discussion of possible mechanisms of BABA-mediated resistance in woody plants.