State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Taian, 271018, Shandong, China.
Plant Cell Rep. 2010 Aug;29(8):927-33. doi: 10.1007/s00299-010-0879-8. Epub 2010 Jun 1.
Inflorescence regeneration in vitro provides a simplified approach for the study of inflorescence development. In this study, high frequency of regenerated inflorescences was established using Arabidopsis stage-10 pistil as the explants on the inducing medium containing the 2 mg/L zeatin and 0.01 mg/L indole-3-acetic acid. TERMINAL FLOWER 1 (TFL1) expression was detected in callus at 6 days after transferred to inducing medium, and LEAFY (LFY) expression was detectable subsequently, suggesting that both genes play important roles as they function on inflorescence development in the plant. To investigate the formation of the stem cell organizing center, we examined the WUSCHEL (WUS) and CLAVATA3 (CLV3) expression within callus during inflorescence regeneration. WUS signals start to accumulate on callus at 4 days after induction, and then, the CLV3 signals are induced on callus at 5 days on the inflorescence-inducing medium. The expression domain of WUS is below that of CLV3, indicating that the patterns of the organizing center and stem cell formation are similar to that in zygotic and somatic embryogenesis. However, more cells of the organizing center were observed within callus than pro-embryo, suggesting that inflorescence differentiation requires more cells of the organizing center. Furthermore, it was found that the WUS expression is controlled by the ratio of cytokinin with auxin. The results suggest that other factors besides WUS and CLV3 are required for inflorescence regeneration.
花序的体外再生为研究花序发育提供了一种简化的方法。在这项研究中，以拟南芥 stage-10 雌蕊为外植体，在含有 2mg/L 玉米素和 0.01mg/L 吲哚乙酸的诱导培养基上，建立了高频再生花序的方法。在转移到诱导培养基 6 天后，在愈伤组织中检测到 TERMINAL FLOWER 1（TFL1）的表达，随后可以检测到 LEAFY（LFY）的表达，这表明这两个基因在植物花序发育中发挥重要作用。为了研究茎干细胞组织中心的形成，我们在花序再生过程中检查了愈伤组织中的 WUSCHEL（WUS）和 CLAVATA3（CLV3）的表达。在诱导后 4 天，WUS 信号开始在愈伤组织中积累，然后在诱导 5 天，CLV3 信号在花序诱导培养基上诱导。WUS 信号的表达域低于 CLV3 信号的表达域，这表明组织中心和干细胞形成的模式与合子和体细胞胚胎发生中的模式相似。然而，与原胚相比，愈伤组织中观察到更多的组织中心细胞，这表明花序分化需要更多的组织中心细胞。此外，还发现 WUS 的表达受细胞分裂素与生长素比例的控制。这些结果表明，除了 WUS 和 CLV3 之外，花序再生还需要其他因素。
