The 55th NIBB Conference
Frontiers of Plant Science in the 21st CenturyConference Review |
Reports |
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Report on the Panel Discussion
4. Super Plant−A powerful tool for post-Arabidopsis study
Bo Sun (National University of Singapore, Singapore) Post-Arabidopsis studies involve many aspects of plant science inquiry: one of them is how to carry out further developmental studies on certain kinds of organs at specific developmental stages.
For example, to carry out studies on flower development, we usually harvest tissues based on simple visual examination. This typically yields 50 to 100 mg of total RNA per sample, which includes 10 to 20 inflorescences harboring inflorescence meristems and flower buds up to stage 10 (with an average diameter of around 0.5 mm). However, this method has major limitations that may make it impossible to carry out organ- and stage-specific studies. First, every inflorescence sample contains stage 1 to 10 flower buds, among which stage 3 to 5 flower buds only account for 1% of the total volume. This immense volume dilution makes it extremely difficult to analyze biological processes happening in the early-stage flowers. Second, each flower later than stage 6 contains 4 clear whorls of floral organs: from outermost to innermost, they are sepals, petals, stamens, and carpels, respectively. It would be very tedious and difficult to harvest each single type of tissue from every tiny flower, and it could also lead to stress responses in the flowers. Currently, several techniques are potentially available for solving these two problems. They include cell sorting, laser capture microdissection and immuno-purification of polysomal complexes. However, all of these methods give rise to very low yields that can hardly satisfy the demands of large-scale analyses such as proteomics, lipidomics, and metabolomics assays. Thus, finding an efficient way to solve the above-mentioned two problems are of great interest. Broccoli, a common vegetable consisting of numerous flower buds blocked at an early developmental stage, stimulated us to look for an Arabidopsis counterpart. ap1 cal 35S::AP1-GR (Wellmer et al., 2006) was reported to have the same inflorescence structure as broccoli, and the transgene it carries can trigger synchronized flower development upon dexamethasone (DEX) treatment. Use of this plant allows us to avoid stage-specific problems. To solve the problem of mixed flower organs, we can manipulate flower pattern formation by constructing transgenic plants on the basis of the ABC model. For example, when we overexpress both B and C class genes, all floral organs will be homeotically changed into stamens. Combining these two feasible approaches, we constructed transgenic plants producing only certain types of floral organs in a time-course synchronized manner. These “super plants” may allow us to efficiently carry out further post-Arabidopsis analysis. We are now able to perform studies in genetics, transcriptomics, proteomics, lipidomics, and metabolomics in organ-specific and stage-specific manners. The “super plant” growth mode could also be applied to the study of economic plants in the near future. ≫ Audience comments and questions |
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