Plant Molecular Biology Lab, Jain R&D Lab, Jain Hills, Jain Irrigation Systems Limited, Jalgaon 425001, India.
Plant Gene Expression Lab, CSIR-National Botanical Research Institute, Lucknow 226001, India.
Tree Physiol. 2018 May 1;38(5):772-784. doi: 10.1093/treephys/tpx154.
FLOWERING LOCUS T (FT) and TERMINAL FLOWER1/CENTRORADIALIS (TFL1/CEN) are the key regulators of flowering time in plants with FT promoting flowering and TFL1 repressing flowering. TFL1 also controls floral meristem identity and its maintenance. In this study we have characterized two pomegranate (Punica granatum L.) TFL1/CEN-like genes designated as PgTFL1 and PgCENa. The expression of PgTFL1 and PgCENa fluctuated through alternate pruning and flowering cycles, being highly expressed during the vegetative phase (immediately after pruning) and decreasing gradually in the months thereafter such that their lowest levels, especially for PgCENa coincided with the flowering phase. Both the genes are able to functionally suppress the Arabidopsis tfl1-14 mutant flowering defect. Their expression in Arabidopsis resulted in delayed flowering time, increased plant height and leaf number, branches and shoot buds as compared with wild type, suggesting that PgTFL1 and PgCENa are bonafide homologs of TFL1. However, both the genes show distinct expression patterns, being expressed differentially in vegetative shoot apex and floral bud samples. While PgTFL1 expression was low in vegetative shoot apex and high in flower bud, PgCENa expression showed the opposite trend. These results suggest that the two TFL1s in pomegranate may be utilized to control distinct developmental processes, namely repression of flowering by PgCENa and development and growth of the reproductive tissues by PgTFL1 via distinct temporal and developmental regulation of their expression.
开花时间是植物生长发育的重要生物学过程，对植物的生长、繁殖和适应环境都具有重要意义。FT 和 TFL1/CEN 是植物开花时间的关键调控因子，FT 促进开花，TFL1 抑制开花。TFL1 还控制花分生组织的身份和维持。在本研究中，我们鉴定了两个石榴（Punica granatum L.）TFL1/CEN 样基因，分别命名为 PgTFL1 和 PgCENa。PgTFL1 和 PgCENa 的表达在交替修剪和开花周期中波动，在营养期（修剪后立即）高度表达，并在随后的几个月中逐渐降低，以至于它们的最低水平，特别是 PgCENa，与开花期相吻合。这两个基因都能够在拟南芥 tfl1-14 突变体中功能上抑制开花缺陷。它们在拟南芥中的表达导致开花时间延迟，植株高度和叶片数量增加，与野生型相比，分枝和芽数增加，表明 PgTFL1 和 PgCENa 是 TFL1 的真正同源物。然而，这两个基因表现出不同的表达模式，在营养茎尖和花芽样本中表达不同。PgTFL1 在营养茎尖的表达较低，在花芽中表达较高，而 PgCENa 的表达则相反。这些结果表明，石榴中的两个 TFL1 可能用于控制不同的发育过程，即 PgCENa 抑制开花，PgTFL1 通过其表达的不同时间和发育调节来促进生殖组织的发育和生长。
