Plant Molecular Biology Lab, Jain R&D Laboratory, Jain Irrigation Systems Limited, Agri Park, Jalgaon, India.
Plant Gene Expression Lab, CSIR-National Botanical Research Institute, Lucknow, India.
Physiol Plant. 2022 Jan;174(1):e13620. doi: 10.1111/ppl.13620.
Flowering in angiosperms is a crucial event that marks the transition from the vegetative to the reproductive phase. In many perennials, pruning is an important horticultural practice that induces synchronized and profuse flowering. In pomegranate, vegetative growth immediately after pruning is associated with activation of PgCENa, a flowering suppressor of the phosphatidyl ethanolamine binding protein (PEBP) family, while a reduction is associated with synchronous flowering. We show that flowering in pomegranate is activated by expression of another PEBP family member, PgFT1, a homolog of the FLOWERING LOCUS T (FT) gene that promotes flowering. PgFT1 shows a rapid reduction in expression during the extensive vegetative growth immediately after pruning but shows robust expression during synchronous flowering post-pruning, in flower-bearing shoots but not in branches that do not bear flowers. A continuous low-level flowering in the absence of pruning is associated with continuous but reduced expression of PgFT1. Flowering by heterologous expression of PgFT1 in Arabidopsis is affected by a single amino acid change in the C-terminal region of PgFT1, which upon correction, promotes flowering in Arabidopsis. Our study provides insights into the molecular mechanisms by which pruning affects flowering pathways in tropical perennial fruit plants such as pomegranate.
开花是被子植物从营养生长到生殖生长的关键转变。在许多多年生植物中，修剪是一种重要的园艺实践，可以诱导同步和大量开花。在石榴中，修剪后立即进行的营养生长与 PgCENa 的激活有关，PgCENa 是磷酸乙醇胺结合蛋白（PEBP）家族的开花抑制物，而减少与同步开花有关。我们表明，另一个 PEBP 家族成员 PgFT1 的表达激活了石榴的开花，PgFT1 是促进开花的 FLOWERING LOCUS T (FT) 基因的同源物。在修剪后立即进行的广泛营养生长过程中，PgFT1 的表达迅速减少，但在修剪后同步开花的花茎中表现出强烈的表达，而在不结果的枝条中则没有表达。在没有修剪的情况下持续的低度开花与 PgFT1 的持续但减少的表达有关。在拟南芥中异源表达 PgFT1 的开花受到 PgFT1 C 末端区域单个氨基酸变化的影响，该变化在纠正后促进了拟南芥的开花。我们的研究提供了对修剪如何影响石榴等热带多年生果树植物开花途径的分子机制的深入了解。
